Note: Descriptions are shown in the official language in which they were submitted.
CA 02577174 2008-08-18
TITLE:
INTRALIIMINAL RADIATION TREATMEIIT BYSTEM
15
GMOSS ZtElNIRZNC3 TO 83LATM 71pPLICATIONS
This application claims the benefits of Canadian Patent File
No. 2,266,638, filed September 23, 1997.
-20 The present invention relates generally to an
intraluminal radiation system for the delivery of treatment
elements by way of a catheter to a selected location within
the intraluminal passageways,of a patient. More particularly,
the present invention relates to an improved transfer device
25 for handling the treating elements and delivering them to the
catheter and an improved catheter assembly.
BACKGROUND OF THE INVENTION
Since the late 1970's balloon angioplasty techniques have
30 become widely used for opening blockages=in coronary arteries.
Briefly, the enlargement of the artery is achieved by
advancing a balloon catheter into a narrowed portion of the
artery and inflating the balloon to expand the diameter of the
artery, thus o"pening the,artery for greater blood flow.
35 Atherectomy techniques, in which blockages are removed or
reduced in size, have also been used to the same end.
While balloon angioplasty has proved an effective way of
opening the coronary arteries, in a significant number of
cases the arteries will narrow again at the location where the
40 balloon was expanded, such narrowing being termed restenosis.
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Restenosis is believed to be caused by formation of scar
tissue at the site of the angioplasty that results from the
injury to the artery caused by the inflation of the balloon.
More recently, intraluminal radiati.on-has been used after
angioplasty or atherectomy to treat the affected area of the
artery to inhibit cell proliferation and wound healing response
and, consequently, help to prevent restenosis. Methods and
apparatus for such intraluminal radiation treatment are disclosed
in the co-pending application, Canadian Patent File No.
' 2,222,706, filed April 4, 1997 which may be referred to for
A further details. This application generally discloses an
apparatus comprising a catheter, which is inserted intraluminally
into the patient and advanced to the site of the area to be
treated, and a transfer device for facilitating either the
hydraulic or pneumatic advancement and retrieval of individual
radioactive treating elements or "seeds" along the catheter to
and from the treatment site.
As with any device inserted into the vascular system, it
must have sufficient integrity to insure that no pieces or
elements are separated from or exit the device into the
vascular system. This is particularly true for the treating
elements which are moved to and from the distal end of the
catheter. Additionally, because the device is intended to use
radioactive treating elements, there is a heightened need for
safety to prevent any unintended exposure of either the
patient or the user to radioactivity.
Use of the apparatus described in the above-identified
co-pending application has suggested several areas where the
device could be improved to reduce the possibility of having
treatment elements escape from the system, thus enhancing
patient and user safety.
Consequently, it is the principal object of the present
invention to provide a transfer device and catheter assembly
that has additional safeguards to protect the patient and
user.
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More particularly, the present invention seeks to provide
a transfer device/catheter assembly in which the catheter
cannot be inadvertently detached from the transfer device
unless all the treating elements reside within the transfer
device. Similarly, it is an object of the present invention
to provide a transfer device/catheter assembly in which none
of the treating elements can exit the transfer device unless
a catheter is connected thereto.
Further, the invention seeks to insure that the hydraulic
or pneumatic pressures to which the transfer device/catheter
assembly is subjected during the advancement and retrieval of
the treating elements does not exceed a predetermined "safe"
pressure.
Still further the invention seeks to provide a method and
system for detecting the presence or absence of treating
elements in the transfer device and for providing a visual
indication of such pressure or absence of treating elements.
SII1rIIdARY OF THE INVENTION
These aspects, and others that will become apparent upon
reference to the following detailed description are
accomplished in one aspect by an actuator assembly for the
transfer device that includes a gate member that is moveable
between a first position that prevents treating elements from
entering the lumen of the catheter and a second position that
permits treating elements to enter the lumen. The gate member
is moveable into the second position only if the catheter is
attached to the transfer device. The actuator assembly
includes a switch member biased into a first position that
prevents movement of the gate member into its second position
unless the switch member is moved out of a first position that
interferes with the movement of the gate member upon the
catheter connector being received in the central opening of
the transfer device. Additionally, a trigger member that is
moveable into locking engagement with the connector when the
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4
connector is received in the central opening is disengageable
by means of a,separate release button.
In another aspect of the invention, a pressure indicator
is provided that includes a transparent elongated cylinder
viewable by the user of the transfer device and housing a
piston which is slidingly received within the cylinder. The
cylinder includes an inlet port through`'which pressurized
fluid can enter, and the piston is biased so that the relative
position of the piston and the cylinder provides a visual
indication of the relative fluid pressure in the transfer
device. The pressure indicator can include a portion having
a inside diameter greater than that portion of the cylinder in
which the piston is disposed and an outlet port= in
communication with the enlarged-diameter portion of the
cylinder. Consequently, when the fluid pressure is sufficient
to move the piston into the enlarged-diameter portion of the
cylinder, fluid escapes passed the piston and exits the
cylinder through the exit port. Alternatively, the pressure
indicator can be connected and.parallel fluid communication
with a separate pressure relief valve of known construction.
In another aspect of the invention, the catheter includes
a connector at its proximal end that is received in a central
opening in the transfer device. The connector includes at
least one detent for securing the connector in the central
opening of the transfer device, the detent having to be
manually actuable to release the catheter from the transfer
device.
In a further aspect of the invention, a method is
provided for.determining whether the treating elements reside
in the transfer device. The method includes encapsulating the
treating elements in a material having a known
wavelength/reflection ratios; shining to lights of different
wavelengths into the area in the transfer device where the
treating elements normally reside before and after being
introduced into the catheter; measuring the ref lectivety of
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the two lights as reflected off the area in the transfer
device; determining the wavelength/reflection ratios of the
reflected light; comparing the measured wavelength/reflection
ratios with the known wavelength/reflection ratios; and
5 indicating whether the measured ratios are substantially the
same as the known ratios.
A system for accomplishing the method described above is
another aspect of the invention and includes a power source;
a first light source optically connected to the targeted
location in the transfer device and that emits a light having
a first wavelength; a second light source optically connected
to the targeted location that emits light having a second
wavelength; a photosensor optically connected to the targeted
location that measures the light reflected off the targeted
location and creating a signal corresponding thereto; a window
detector for determining whether the signal created by
photosensor is within a predetermined band corresponding to a
signal which would be created by light of first and second
wavelengths being reflected off the element; and an indicator
light that is activated if the signal created by the
photosensor is within the predetermined band.
DRAWINGS
Fig. 1 is a schematic drawing of intraluminal radiation
system comprising a transfer device, a delivery catheter, and
a connector for connecting the two.
Fig. 2 is an exploded view of the transfer device of the
present invention.
Fig. 2a is a cross-sectional view of the assembled
transfer device of Fig. 2.
Fig. 3 is a cross-sectional view of the rear housing of
the transfer device.
Fig. 4 is a bottom view of the rear housing of the
transfer device.
Fig. 5 is a perspective view of the fluid control handle.
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Fig. 6 is a perspective view of the fluid control switch.
Fig. 7 is a bottom view of the fluid control switch.
Fig. 8 is a cross-sectional view of the central housing
of the transfer device including the quartz sleeve for holding
the radiation elements.
Fig. 9 is an enlarged sectional view of the portion of
the rear housing of the transfer device that interfaces with
the seed lumen of the quartz sleeve.
Fig. 10 is a plan view of the distal face of the central
housing.
Fig. 11 is a plan view of the actuator switch..
Fig. 12 is a plan view of the gate.
Fig. 13 is a plan view of the proximal face of the gate
housing.
Fig. 14 is a plan view of the distal face of the gate
housing.
Fig. 15 is a plan view of the proximal face of the collar
housing.
Fig. 16 is a plan view of the release trigger.
Fig. 17 is a plan view of the release switch.
Fig. 18 is a top view of the release switch.
Fig. 19 is a plan view of the proximal face of the front
housing.
Figs. 19a-c illustrate the interaction of the release
trigger and release switch during the insertion of the
connector into the trigger device.
Fig. 20 is a side view of the front housing.
Fig. 21a is a schematic drawing of an intraluminal
radiation system embodying the present invention with an
alternate construction for the rear housing of the transfer
device.
Fig. 21b is an exploded perspective view of the rear
housing/fluid control switch of Fig. 21a.
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Fig. 21c is a cross-sectional view of the assembled
transfer device with the alternate embodiment of the rear
housing/fluid control switch of Fig. 21b.
Fig. 22 is a top view of the rear housing of Fig. 21b.
Fig. 23 is a side view of the rear housing of Fig. 21b.
Fig. 24 is a perspective view of the fluid control switch
of Fig. 21b showing the proximal side of the switch.
Fig. 25 is a perspective view of the fluid control switch
of Fig. 21b showing the distal side of the switch.
Fig. 26 is a plan view of the fluid control switch of
Fig. 21b showing the proximal side of the switch. -
Fig. 27 is a plan view of the fluid control switch of
Fig. 21b showing the distal side of the switch.
Fig. 28 is a schematic view of the intraluminal radiation
treatment system of the present invention.
Fig. 29A is perspective view of a further embodiment of
the transfer device of the present invention also showing a
syringe attached thereto.
Fig. 29B is a perspective view similar to Fig. 29A,
except for the top half of the housing of the transfer device
is removed to show its interior construction.
Fig. 30 is a plan view of the housing of the transfer
device of Fig. 29A.
Fig. 31 is an exploded perspective view of the transfer
device of Fig. 29A.
Fig. 32A is a lateral cross-sectional view of the
transfer device of Fig. 29A.
Fig. 32B is a longitudinal cross-sectional view of the
transfer device of Fig. 29A.
Fig. 32C is an enlarged cross-sectional view of one of
the internal components of the transfer device of Fig. 29A.
Fig. 32D is a longitudinal cross-sectional view of the
transfer device of Fig. 29A perpendicular to the cross-
sectional view shown in Fig. 32B.
Fig. 33 is a side view of the transfer device of Fig. 30.
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Figs. 35A-D show a pressure indicator/pressure relief
valve, and its component parts, that can be advantageously
used in the transfer device of Fig. 29A.
Fig. 37 is a perspective view of selected interior
components of the transfer device of Fig. 29A mounted on a
chassis.
Fig. 38 is a perspective view of a release switch for use
in the transfer device of Fig. 29A.
Figs. 39A-B are the perspective views of the components
for the pin gate for use in the transfer device of Fig. 29A.
Figs. 40A-D show the pin gate/release switch safety
interlock used in the transfer device of Fig. 29A.
Figs. 41A-E show the catheter connector and its various
subparts used in the present invention.
Figs. 42A-D show a catheter and its cross-section (Fig.
42D) for use in the present invention.
Figs. 45 is a logic diagram for a treating element
verification system advantageously used with the transfer
device of Fig. 29A.
Figs. 46A-1, 46A-2; 46B; and 46C-1, 46C-2, 46C-3 are
circuit diagrams for performing the functions set forth in the
logic diagram of Fig. 45.
Fig. 47 is a plan view of the housing of a further
embodiment of the transfer device.
Fig. 48 is a perspective view of the transfer device of
Fig. 47 with the top half of the housing removed to show
interior detail.
Fig. 49 is an end view of the transfer device of Fig. 47
looking at the distal end.
Fig. 50 is an exploded perspective view of the transfer
device of Fig. 47.
Figs. 51A and B are longitudinal cross-sectional views of
the transfer device of Fig. 47.
Fig. 51C is a lateral cross-sectional view of the
transfer device of Fig. 47.
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Fig. 52 is an exploded perspective view of the pressure
indicator gauge and pressure relief valve for use in
conjunction with the transfer device of Fig. 47.
Fig. 53 is a cross-sectional view of the pressure
indicator gauge and pressure relief valve of Fig. 52, with the
fluid flow therethrough shown schematically.
Figs. 54A and B are perspective views of the latch body
for use in connection with the transfer device of Fig. 47.
Fig. 55 is a perspective view of the latch sear for use
in conjunction with the transfer device of Fig. 47.
Figs. 56A, B and C show the assembled latch mechanism,
including the latch body, latch sear, and latch button in
perspective, plan, and cross-sectional views, respectively.
Figs. 57A and B show the skirt connector for use in
conjunction with the catheter connector in perspective and
cross-sectional views, respectively.
Fig. 57C is a cross-sectional view of the proximal end of
the catheter connector showing the central plug.
Fig. 58A is a plan view of a catheter Ãor use in the
present invention.
Fig. 58B is an enlarged lateral cross-sectional view of
the catheter of Fig. 58A.
Fig. 58C is an enlarged longitudinal cross-sectional view
of the distal end of the catheter of Fig. 58A.
Fig. 59 is a plan view of a treatment element seed train
for use in the present invention.
Fig. 60 is a logic diagram for the treating element
verification system for use with the transfer device of Fig.
47.
Figs. 61A-1, 61A-2, 61A-3; 61B; and 61C-1, 61C-2 are
circuit diagrams for performing the functions set forth in the
logic diagram of Fig. 60.
Fig. 61D is a schematic diagram for a distribution board
for the treating element verification system of Figs. 60 and
61A-C.
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Figs. 62A-C are printed circuit boards showing the
mechanical outline for use with the treating element
verification system of Figs. 60 and 61A-D.
Fig. 63A is a schematic diagram show-Lng the electrical
5 connections between the various parts of the treating element
verification system.
Fig. 63B is a circuit diagram for an equivalent circuit
to Fig. 63A.
10 DETAILED DESCRIPTION
Turning to the figures of the drawings; Fig. 1
illustrates an intraluminal radiation system 10 according the
present invention comprising a transfer device, generally
indicated by 12, a delivery catheter, generally indicated by
14, and a connector, generally indicated,by 16, for securely
attaching the delivery catheter 14 to the transfer device 12.
The delivery catheter 14 and connector 16 are substantially as
described in the above-identified co-pending application which
may be referred to for further details.
The transfer device 12 functions to h&use and shield a
radiation source train (not shown), which may include non-
radioactive marker seeds, and controls the direction of fluid
flow for priming the transfer device 12 and catheter 14 and
effecting delivery and retrieval of the individual radiation
elements.
The transfer device 12 is shown in exploded view in Fig.
2 and consists of three main assemblies: rear housing and
fluid control switch assembly 18, central housing and actuator
switch/shuttle gate assembly 20, and front housing 22. The
rear housing and fluid control switch assemblies and the
central housing and actuator switch/shuttle gate assembly
disclosed herein are interchangeable with the corresponding
parts disclosed in the above-referenced co-pending application
The rear housing 18 comprises a cylindrical member 24,
preferably made of polycarbonate, that includes two axial
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through-lumens 26 for positioning two screws 28 that connect
the rear housing 18 to the central housing 20. The threads of
the screws 28 can directly engage the polycarbonate material
of the central housing 80 or the internal threads of the
lumens 26 can receive helical, coiled wire inserts which will
be engaged by the threads of the screws 28. Alternatively,
the lumens in the central housing 80 that receive the screws
28 can include internally threaded metal inserts (not shown)
secured therein by, e.g., ultrasonic welding, so that the
threads of the screws 28 engage the internal threads of the
metal inserts, thus providing a more durable connection
between the rear housing 18 and the central housing 80.
The cylindrical member 24 includes a cylindrical recess
30 for placement of a fluid control switch 44, which is
discussed in greater detail below. The cylindrical member 24
includes two luer connectors or fittings 32, 34, preferably
made of a polycarbonate and secured to the cylindrical member
24 by a UV-cure adhesive. The luer fittings 32, 34 may be
either partially or completely recessed within the rear
-housing 18. Luer fitting 32 is received in recess 32a in the
cylindrical member 24 and is in fluid communication with a
fluid inlet channel 36 (best seen in Fig. 3). The luer
fitting 32 connects to a liquid or gas-filled device (not
shown) that is used for hydraulic or pneumatic delivery -and
retrieval of the radiation source train to and from the
delivery catheter 14.
Luer fitting 34 is received in recess 34a of the
cylindrical member 24 and is in fluid communication with a
fluid exit channel 38 (Fig. 4). The luer fitting 34 can
optionally be connected to a fluid collection bag or reservoir
(not shown). The cylindrical member 24 also includes a
hydraulic return channel 40 (Fig. 4) and a seed delivery
channel 42 (Fig. 3). Each of the channels 36, 38, 40, and 42
communicate with the cylindrical recess 30.
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A fluid control switch 44 selectively provides access
between the various channels 36, 38, 40, and 42 to send and/or
retrieve the radioactive treatment elements and marker seeds
from the delivery catheter 14. To facilitate easy
manipulation of the fluid control switch 44, a paddle-shaped
control handle 46 is secured to the fluid control switch 44
and cylindrical member 24 by means of a retention screw 48
that extends through a central bore in the handle 46 and
switch 44 and into a bore in the cylindrical housing 24. The
bottom of the retention screw 48 abuts a set screw 49 to limit
the movement of the screw 48 and prevent the screw 48 from
being unscrewed by operation of the switch 44. A locking cap
50 closes the central bore in the handle 46. As best seen in
Fig. 5, the fluid control handle 46 includes a paddle-like
portion 52 which may be contoured or otherwise ergonomically-
shaped to provide the user with improved control and easier
manipulation of the fluid control switch 44.
Optionally, the head of the retention screw 48 may be
notched so that a locking pin (not shown) may fit through it.
Such a locking pin would prevent rotational movement of the
retention screw 48 so that counterclockwise movement of the
fluid control handle 46 would not loosen the screw 48. A
shallow hole in the fluid control handle 46 where the head of
the retention screw 48 rests would receive such a locking pin=.
In order to limit the degree to which the fluid control
switch 44 can be rotated, the bottom of the switch 44 includes
a fluid control slot 54 (Figs. 6, 7) which cooperates with an
alignment pin 56 (Fig. 2) that is secured in a hole in the
recessed area 30 of the rear housing member 18. _To positively
locate the switch in "off," "send," and "return" positions,
the fluid control switch 44 also includes three dimples 58
(Fig. 6) that interact with a detent ball 60 and compression
spring 62 (Fig. 2), which are housed in a short lumen 64 (Fig.
3) within the cylindrical member 24.
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As best seen in Fig. 7, the bottom of the fluid control
switch 44 includes a C-shaped connector channel 66 and an
elliptical-shaped connector channel 68. The control switch 44
is relieved about the C-shaped and elliptical-shaped connector
channels 66, 68 in order to receive o-rings 70 and 72,
respectively, which seal the connector channels 66, 68 against
the recess 30. To further prevent leakage around the fluid
control switch 44, an o-ring 74 is received in an o-ring
channel 76 about the exterior of the fluid control switch 44
(best seen in Fig. 6) and an o-ring 78 may be received by an
o-ring channel about the distal opening of the switch 44. The
o-rings 70, 72, 76 and 78 are preferably made of Buna-N or
ethylene propylene.
In operation, when the fluid control switch 44 is in the
"send" position, both the fluid injection channel 36 and the
seed delivery channel 42 communicate through the C-shaped
connector channel 66. Simultaneously the hydraulic return
channel 40 and the fluid exit channel 38 communicate through
the elliptical-shaped connector channel 68. Thus, fluid is
allowed to flow through the fluid injection channel 36 through
the C-shaped connector channel 66 and into the seed delivery.
channel 42. Fluid that bypasses the treating elements reaches
the distal end of the delivery catheter 14 and returns to the
hydraulic return channel 40 and is allowed, through the
elliptical-shaped connector channel 68, to flow through the
exit channel 38.
When the fluid control switch 44 is in the "return"
position, bot-h the fluid injection channel 36 and the
hydraulic return channel 40 are aligned through the C-shaped
connector channel 66. Simultaneously, both the seed delivery
channel 42 and the fluid exit channel 38 are aligned though
the elliptical-shaped connector channel 68. Consequently,
fluid is allowed to flow through the fluid injection channel
36 into the C-shaped connector channel 66 and through the
hydraulic return channel 40. As the treating elements are
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14
forced hydraulically from the distal end of the catheter back
to the transfer device 12, fluid is allowed to flow from the
seed delivery channel 42 to the fluid exit channel 38 through
the elliptical-shaped connector channel 68.
When the fluid control switch 44 is in the "off"
position, the fluid injection channel 36 is the only channel
aligned with the C-shaped connector channel 66. Thus, no
outlet exists for fluid flowing to the connector channel 66
from the fluid injection channel 36.
The transfer device 12 preferably includes a pressure
relief valve (not shown) so that the system 10 cannot be over-
pressurized. The valve would open to allow fluid in the
system 10 to escape once the fluid pressure exceeded a
certain, pre-determined value. Once the pressure in the
system returns to a safe level, the valve would close. In one
form, the valve may be spring-actuated, so that fluid pressure
greater than the pre-deter;ained value compresses the spring to
open the valve, the valve being closed by the spring when the
fluid pressure is reduced to below the pre-determined value.
In addition, the transfer device 12 preferably includes an
accumulator (not shown) or similar apparatus for maintaining
a substantial amount of pressure against the radiation source
train and marker seeds while they are positioned at the distal
end of the catheter 14 so that they cannot migrate away from
the distal end of the catheter 14 and the treatment site
during radiation treatment. The accumulator may also be used
to maintain a substantial amount of pressure against the
treating elements and marker seeds so that they will remain
completely within the lu:nen of the quartz sleeve 84 and
visible to the users when they are not being used for
radiation treatment.
Distal of the rear housing 18 and connected thereto is
the central housing and actuator switch/shuttle gate assembly
20. Proper alignment of the rear housing 18 and the central
housing and actuator switch/shuttle gate assembly 20 may be
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assured by alignment pins (not shown). The assembly 20
includes a central housing 80 having a central lumen 82 for
receipt of the quartz sleeve 84 (Fig. 8) which extends the
entire length of the central housing 80 and in which the
5 radiation source train or seeds are stored.
The central housing 80 is cylindrical in shape and
preferably made of clear Lexan or clear polycarbonate. The
quartz sleeve 84 is preferably made of natural or synthetic
quartz or quartz glass (fused quartz), or other materials
10 consisting of natural or synthetic fused silica. A lumen 86
extends the entire length of the quartz sleeve 84 and the
radiation source seeds and marker seeds are stored within the
lumen 86 when the seeds are not being delivered to the
treatment site. The quartz sleeve 84 is used to shield the
15 radiation emitted from the source train so that the transfer
device 12 can be handled safely. The quartz material does not
break down as a result of storing the radiation-emitting
treatment seeds and also remains clear so that the seeds can
be visually detected. The quartz rod is of sufficient
thickness to block at least 99 percent of the radiation. In
practice, a thickness of 1 cm has been found to be sufficient.
In order to more easily discern the presence of the
radiation source seeds and marker seeds within the quartz
sleeve 84, the sleeve is of one uniform diameter and has no
steps or o-rings disposed thereon. Thus, the entire length of
the quartz sleeve can be seen. The lower half of the quartz
sleeve 84 can be covered with a white film, preferably vinyl
or Tyvek , to create a contrasting background for the source
seeds. Additionally or alternatively, a magnifying piece may
either encase the quartz sleeve 84 or lie along the top of the
quartz sleeve to better permit visualization of the radiation
source seeds. Additionally, a light source could be utilized
to better visualize the source and marker seeds.
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As best seen in Figs. 3 and 9, a rear housing insert 88
with a lumen therethrough comprises an intermediate member
between the rear housing 18 and central housing 20 for
providing fluid communication between the seed delivery
.5 channel 42 and the lumen 86 of the quartz sleeve 84 through
lumen 90 of the insert 88. The lumen .90 is L-shaped and
precludes the treating elements from migrating into the rear
housing 18, while insuring fluid communication between the
rear housing lumens and the quartz lumen.
A smaller, off-axis through-lumen 92 extends through the
central housing 80 (Fig. 10) and is a continuation of the
hydraulic return channel 40 in the rear housing 18. Fluid
leakage between the connection of the return lumen 40 and the
rear housing 18 and the return lumen 92 in the central housing
80 is prevented by a means of an o-ring 94 (Fig. 2),
preferably made of Buna-N or ethylene propylene
An actuator switch 96 is located at the distal end of the
central housing 80 that pivots a shuttle gate 98 to operate
the system. The actuator switch 96 allows for two positions:
"connect/prime" and "send/ retrieve. !' The connect/prime mode
allows for connection of the connector 16 (Fig. 1) through the
transfer device 12. After being connected, the connect/prime
mode allows for flushing and priming of the transfer device 12
and the catheter 14 without the delivery of the radiation
source train.
The send/retrieve mode allows for the delivery of the
radiation source train and marker seeds to, and retrieval
from, the distal end of the catheter 14. The send/retrieve
mode of the actuator switch 96 cannot be accessed unless the
connector 16 has been locked into the transfer device 12.
This prevents inadvertent delivery of the radiation source
train to any location other than the delivery catheter 14. To
this end, the distal face of the central housing 80 includes
a recessed area 100 (Fig. 10) in the general shape of a
squared U. The recess 100 receives the proximal end of
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positioning pin 102 (Fig. 2) to positively lock the actuator
switch 96/shuttle gate 98 in position for two modes discussed
above.
The actuator switch 96 is made of a hard plastic
material, such as Acetal or Delrin. The actuator switch 96
has a top portion 96a (Fig. 11) that has a depression so that
the user may use solely a thumb or a f inger to operate the
switch. The actuator switch also includes two slightly curved
arms 96b that extend outwardly and downwardly from the
midsection of the switch 96. Two rectangular legs 96c extend
from the bottom of the switch 96, with each leg 96c having a
hole 96d therethrough for receipt of the positioning pin 102.
Between the two legs 96c, a hollow portion extends into the
midsection of the switch 96 for receiving the top portion of
the gate 98 and a compression spring 104 (Fig. 2).
The shuttle gate 98 is made of a plastic material, such
as Acetal or clear polycarbonate, and is of sufficient
thickness to insure stability when the gate pivots. The
shuttle gate 98 includes a body portion 106 (Fig. 12) that has
a shoulder and tapers inward to a curved bottom. The body
portion 106 includes a hole 107 for receipt of a compression.
spring 105 (Fig. 2) which biases the shuttle gate 98 toward
the connect/prime mode. A neck 108 extends upwardly from the
body portion 106 of the gate 98 and includes a hole 110 in
which the compression spring 104 is received. Neck 108 also
includes a slot 112 for receiving the positioning pin 102.
The gate 98 includes a through hole 114 at its bottom for
receipt of a pivot pin 116 (Fig. 2), so that the gate 98 can
rotate about the pivot pin 116. The gate 98 also includes a
hole 118 between the axis pin hole 114 and the positioning
slot 112 that is large enough to allow the treating elements
to pass therethrough. An o-ring groove 120 exists on each
side of the gate for receiving an o-ring 122 (that encircles
the proximal opening of the seed hole) and an o-ring 124 (that
encircles the distal opening of the seed hole). The o-rings
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122, 124 (Fig. 2) are located so that when the actuator
switch/shuttle gate are moved between their various locations,
the o-rings do not travel across the edges of any other parts,
thus reducing wear on the o-rings and providing for smoother
action when operating the gate 98.
In operation, the compression spring 104 biases the
actuator switch 96 away from the shuttle`gate 98. When the
actuator switch 96 is pressed downward against the force of
the compression spring 104, the positioning pin 102 is moved
towards the bottom leg of the U-shaped recess 100 in the
central housing 80 and the collar housing 146 to permit
movement of the actuator switch 96 and the shuttle gate 98
between the two positions.
The shuttle gate 98 is secured to the distal end of the
central housing 80 by a gate housing 126. As best seen in
Fig. 13, the proximal side of gate housing 126 has a recessed
area 128 in the general shape of shuttle gate 98 and a
generally rectangular opening 129. When the gate 98 is in
this recessed area 128 the neck 108 extends beyond the gate
housing 126. The gate housing 126 includes a seed lumen 130
which is chamfered at both its proximal and distal ends to
facilitate the delivery of the treating elements. (The seed
lumens in the other housings may also be chamfered at their
ends to facilitate delivery of the treating elements.)
The distal side of the gate housing 126 (best seen in
Fig. 14) has a circular recessed area 132 with a beveled edge
encircling the seed lumen for better alignment with the
connector 16. For alignment of the gate housing 126 with the
central housing,80 and a collar housing 146, the gate housing
126 also has holes 136 for receiving screws 138 (Fig. 2) and
an alignment hole 140 for receiving alignment pins 142, 144
(Fig. 2). The gate housing 126 also includes a fluid return
channel 148 (a continuation of the fluid return channel 92 in
the central housing 80) and an annular groove 150 on the
proximal side of the gate housing 126 for receipt of an o-ring
CA 02577174 2008-08-18
19
152 (Fig. 2). An aperture 154 on the proximal side of the
gate housing receives the distal end of the pivot pin 116 for
the shuttle gate 98.
The collar housing 146 is positioned intermediate the
gate housing 126 and a front housing 156. The proximal face
of the collar housing 146 (Fig. 15) is sha,ped similarly to the
distal face of the central housing 80 (Fig. 10) and includes
a recess 158 that compliments the recess 100 in the central
housing 80 and receives the distal end of the positioning pin
102 of the shuttle gate 98.
The collar housing 146 has an enlarged central opening
160 for receiving the connector 16 (Fig. 1) and which is
relieved on the proximal side of the collar housing 146 for
receipt of o-ring 134 (Fig. 2). A rectangular opening 161
extends through the collar housing 146. The collar housing
146 includes a fluid return channel 162 (a continuation of the
fluid return channel 148 in the gate housing 126) with an
annular o-ring groove surrounding the proximal opening thereof
for receipt of o-ring 164 (Fig. 2). An alignment hole is also
included for receipt of alignment pin 144 to align the collar
housing 146 with the gate housing 126 and another hole for
receiving alignment pin 166 for aligning the collar hosing 146
with the front housing 156.
Cut-outs on the distal face of the collar housing 146,
with complimentary cut-outs in the proximal face of the front
housing 156, receive a release button 168, release switch 170,
and release trigger 172, which cooperate to receive and lock
the connector 16 into the transfer device 12 and to release
the connector 16 from the transfer device 12 as well. The
interaction of the release button 168, release switch 170, and
release trigger 172 are described in greater detail below.
The release trigger 172 (Fig. 16) includes a generally
rectangular body 172a with two legs 172b extending therefrom.
A sloped relief of parabolic shape 172c on the distal side of
the trigger 172 makes up the edge between the two legs 172b.
CA 02577174 2008-08-18
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The top of the release trigger 172 includes a shallow bore
172d for receiving one end of a compression spring 174 (Fig.
2).
The release switch 170 (Fig. 17) includes an elongated
5 rectangular body 170a with a curved and notched ramp 170b at
one end and a protruding arm 170c (Fig. 18) at the other end.
The arm 170c includes a bore 170d for receipt of a dowel pin
176 (Fig. 2). The release button 168 is secured to the
release switch 170 by means of a screw 178 (Fig. 2) that is
10 received in a hole 170e in the release switch 170.
Alternatively, the release button 168 may be an integral part
of the release switch 170.
The front housing 156 completes the distal end of the
transfer device 12 and includes a central lumen 180 (Fig. 19)
15 for receiving the connector 16. The distal portion of the
central lumen 180 is relieved at 181 (Fig. 20) to seat two o-
rings that fit on the outside of the connector 16 when the
connector is locked into the transfer device 12 (to seal the
connection between the connector 16 and a fluid return lumen
20 184 in the front housing 156. The front housing 156 includes
two holes 182 for receiving the screws 138 that secure the
front housing 156, collar housing 146, and gate housing 126 to
the central housing 80. As described above, the lumens in the
central housing 80 that receive the screws 138 can optionally
be lined with helical, coiled wire inserts or include threaded
metal inserts to provide a more durable connection. The front
housing 156 also includes a fluid return lumen 184 (a
continuation of the fluid return lumen 162 in the collar
housing 146) that has an annular o-ring groove surrounding the
proximal opening for receipt of an o-ring 186 (Fig. 2). An
aperture in the proximal face receives alignment pin 166 for
insuring alignment of the front housing 156 with the collar
housing 146.
Turning now to the operation of the actuator
switch/shuttle gate, when the gate 98 is in the closed
CA 02577174 2008-08-18
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21
position (and the connector 16 is not connected to the
transfer device 12), the release switch 170 rests upon a
compressed spring 190 (Fig. 2) with one of the legs 172b of
the release trigger 172 engaging the uppermost portion of the
ramp 170b of the release switch 170 to keep the release switch
pressed down against the compressed spring 190 (Fig. 19a) . In
this condition, the release button 168 is completely recessed
in the opening between the collar housing 146 and front
housing 156. The end of the dowel pin 176 extends through the
openings 129 and 161 in the gate housing 126 and collar
housing 146, respectively, at the bottom of the openings 129,
161 and is positioned adjacent to gate 98 to prevent the gate
from pivoting to and engaging in the seed transit mode.
When the connector 16 is inserted into the central lumen
180 of the front housing 156, the proximal end of the
connector 16 contacts the sloped relief 172c of the release
trigger 172 to force the trigger 172 upwardly, while
simultaneously compressing the spring 174 (Fig. 19b). As the
release trigger 172 moves away from the release switch 170,
movement of the release switch 170 is no longer impeded and
the release switch, biased by the compressed spring 190, moves
upwardly until the curved ramp 170b engages an undercut
section on the connector 16. This locks the connector 16 into
the transfer device 12. When the release switch 170 is moved
to lock onto the connector 16, the release button moves out of
its recessed area to visually confirm that the connector 16 is
locked into the transfer device (Fig. 19c). Simultaneously,
the dowel pin 176 moves to the top of the openings 129, 161 so
that it no longer prevents the gate 198 from engaging into the
seed transit mode.
The actuator switch 96 can now be moved from the
connect/prime mode to the seed transit mode by pushing down on
the actuator switch 96 to force the positioning pin 102
downward to the bottom of the grooves 100 (in the central
housing 80) and 158 (in the collar housing 146). While
CA 02577174 2008-08-18
= WO 98/11936 PCTIUS97/16856
22
maintaining a downward force on the actuator switch 96, a
horizontal force is then applied to the actuator switch 96 to
move the positioning pin 102 through the horizontal groove of
the recesses 100, 158 to the other vertical groove. The
switch 96 is then released and the positioning pin 102 moves
up to the top of the vertical groove to place the switch 98 in
the seed transit mode. When the actuator switch 96 is engaged
in the seed transit mode, the gate 98 is positioned so that a
portion of the gate 98 now occupies the same space that was
occupied by the dowel pin 176 in the connect/prime mode.
To remove the connector 16 from the transfer device the
actuator switch 98 is moved into the connect/prime mode after
all the treating elements and marker seeds have been returned
to the quartz sleeve 84. Once the actuator switch 98 is in
the connect/prime mode, the release button 168 is pressed
inwardly to move the release switch 170 downwardly against the
spring 190. The dowel pin 176 simultaneously moves so as to
prevent movement of the gate 98 back to the seed transit mode.
The connector 16 can then be manually withdrawn from the
transfer device. Withdrawal of the connector 16 allows the
release trigger 172 to be forced by the spring 174 to drop.
down and reposition one of its legs 172b in front of the ramp
170b, returning the release button 168, the release switch
170, and the release trigger 172 to their initial positions.
The release button 168 cannot be activated while the
actuator switch 96 is in the seed transit mode. In the seed
transit mode, the gate 98 is positioned so that it hinders
downward movement of the dowel pin 176. Because the dowel pin
176 is connected to the release switch 170, downward movement
of the release switch 170 is also impeded and the curved ramp
170b cannot disengage from the connector 16.
Turning to Figs. 21-27, there is seen a further
embodiment of the rear housing/fluid control switch for use in
the transfer device 12 of the present invention. As seen in
CA 02577174 2008-08-18
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23
Fig. 21b, the rear housing 200 is generally cylindrical in
shape and includes two axial through-lumens 202 for
positioning two screws (such as screws 28 in Fig. 2) to secure
the rear housing 200 to the central housing. The rear housing
includes two recesses 204, 206 for receipt of luer fittings or
connectors similar to connectors 32, 34 shown in Fig. 2. Such
luer fittings would be secured in the recesses 204, 206 by
means of an adhesive. The luer fittings may be partially or
completely recessed within the rear housing 200. Preferably
the luer connector received in recess 204 provides for
attachment to a liquid or gas filled device (not shown) that
is used for hydraulic or pneumatic delivery and retrieval of
the radiation source train and marker seeds to and from the
delivery catheter 14. The luer connector secured in recess
206 attaches to a fluid collection bag (not shown).
Toward the distal end of the rear housing 200 there is a
cylindrical bore 208 that receives the fluid control switch
210, which will be described in detail later. The diameter of
the cylindrical bore 208 is slightly smaller than the largest
diameter of the fluid control switch 210 so that the fluid
control switch 210 fits tightly within the bore 208. A fluid
inlet channel 212 connects recess 204 to the cylindrical bore
208 (Fig. 22) ; a fluid exit channel 214 connects recess 206 to
the cylindrical bore 208 (Fig. 23); a fluid return/s-eed
retrieval channel 216 connects the cylindrical bore 208 with
an opening 218 in the distal face of the rear housing 200
(Fig. 22 or 23); and a fluid return/seed delivery channel 220
connects the cylindrical bore 208 to a central distal opening
222 including a rear housing insert 224 (similar to insert 88
in Fig. 9) (Fig. 22 or 23).
The fluid control switch 210 is a solid cylinder,
preferably made of a white or clear Teflon material to allow
smooth movement of the cylinder 210 within the central bore
208, and includes four fluid channels (described below) for
selectively connecting channels 212 and 214 with channels 216
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WO 98/11936 PCTIUS97/16856
24
and 220. The switch 210 includes a rectangular cut-out 226 at
its upper end for receipt of handle 228 the rectangular cut-
out 226 is sized so that the distal end 230 of the handle 228
fits snugly within it.
The handle 228 is enlarged at its distal end 230 so that
it has an overhang or step 231. When the distal end 230 of
the handle 228 is fitted into the rectangular cut-out 226 in
the fluid control switch 210, and the fluid control switch 210
is positioned in the cylindrical bore 208 of the rear housing
200, the entire overhang 231 is positioned within the
circumference of switch 210, and the overhang 231 of the
handle 228 abuts the sidewall of the central bore 208, thus
preventing removal of the handle 228 from the cut-out 226 and
securing the handle 228 within the switch 210.
The fluid control switch 210 includes four channels 242,
244, 246, and 248 for selectively connecting the fluid inlet
channel 212 and fluid exit channel 214 with the fluid
return/seed retrieval channel 216 and fluid return/seed
delivery channel 220. As best seen in Figs. 26 and 27, the
fluid control switch 210 includes a seed delivery channel 242,
a fluid return channel 244, a seed retrieval channel 246, and.
a fluid return channel 248.
In operation, when the fluid control switch 210 is in the
"send" position, both the fluid inlet channel 212 and the seed
delivery channel 220 in the rear housing 200 communicate
through the seed delivery channel 242 in the fluid control
switch 210. Simultaneously, the fluid exit channel 214 and
fluid return/seed retrieval channel 216 in the rear housing
200 communicate through fluid return channel 248 in the fluid
control switch 210. Thus, fluid is allowed to flow from,
e.g., a syringe, through the fluid inlet channel 212, through
the seed delivery channel 242 in the switch 210, and into the
seed delivery channel 220 to advance the treatment elements to
the distal end of the delivery catheter. Fluid that bypasses
the treatment elements reaches the end of the delivery
CA 02577174 2008-08-18
= VVO 98/11936 PCT/US97/16856
catheter and returns to the fluid return/seed retrieval
channel 216 and is allowed, through the fluid return channel
248 in the switch 210, to flow through the fluid exit channel
214 and into, e.g., a fluid collection bag.
5 When the fluid control switch 210 is in the "retrieval"
position, both the fluid inlet channel 212 and the fluid
return/seed retrieval channel 216 in the rear housing 200
communicate through seed retrieval channel 246 in the fluid
control switch 210. Simultaneously, both the fluid exit
10 channel 214 and the seed delivery channel 220 in the rear
housing 200 communicate through the fluid return channel 244
in the fluid control switch 210. Consequently, fluid is
allowed to flow through the fluid inlet channel 212, into the
seed retrieval channel 246, through the fluid return/seed
15 retrieval channel 216, and into the catheter to hydraulically
force the treating elements from the distal end of the
catheter back to the transfer device. Simultaneously, fluid
is allowed to flow fron the seed delivery channel 220, through
the fluid return channel 244, into the fluid exit channel 214,
20 and out of the transfer device.
When the fluid control switch 210 is in the "off"
position, none of the channels 212, 214, 218, 220, 242, 244,
246, and 248 communicate with each other. Thus, no outlet
exists for any fluid from the fluid inlet channel 212. -'
25 The fluid control switch 210 includes a channel or groove
250 that receives o-ring 252 to prevent leakage out of the
cylindrical bore 208 (Figs. 24, 25). The fluid control switch
210 also includes three areas of enlarged diameter, generally
indicated by 254, to prevent cross-talk among the fluid
channels 242, 244, 246 and 248. These areas of enlarged
diameter correspond with the openings of the channels 242,
244, 246, 248 and create a tight seal about the fluid
openings. Alternatively, o-rings could be used in place of
the areas of greater diameter.
CA 02577174 2008-08-18
NN'O 98/11936 PCT/US97116856
26
On the distal face of the fluid control switch 210 there
is an oblong opening 232 (Fig. 27) which extends radially
along the face of the switch 210 so that, when the switch 210
is placed within the cylindrical bore 208, the oblong opening
232 aligns with a short through lumen 234 in the rear housing.
The oblong opening 232 terminates internally of the fluid
control switch 210 with three dimples 236 which interact with
a compression spring 238 and detent pin 240 (Fig. 21b) to
assist in the positioning of the fluid control switch 210
(similar to the compression spring 62 and ball detent 60 shown
in Fig. 2). The ends of the oblong opening 232 act as stops
in conjunction with the detent pin 240 to limit the degree to
which the fluid control switch 210 can be rotated.
The detent pin 240 has a ball-shaped end that rests
within the dimples 236. In the "off" position the detent pin
240 rests within the middle dimple. As the fluid control
switch 210 is moved to either the "send" or the "retrieval"
mode, the middle dimple moves away from the detent pin 240,
while either end dimple moves towards the pin. As the switch
210 and dimples rotate, the detent pin is pushed back against
the compression spring 238. As one of the end dimples becomes
aligned with the pin, the force of the spring 238 propels the
pin 240 forward so that the ball of the pin 240 rests within
the dimple. Because when the.pin moves away from the dimples
during rotation of the cylinder it does not move'outside of
the opening 232, the pin secures the cylinder 210 within the
rear housing 200 at all times.
Turning to Figs. 29-33, there is seen an improved
transfer device 300 for handling and delivering the treating
elements in conjunction with the intraluminal radiation system
of the present invention. In contrast to the previously
described transfer devices 12, the transfer device 300
includes an ergonomically designed exterior that is more
easily gripped by the user. Additionally, the various
internal components of the transfer device 300 are unitized
CA 02577174 2008-08-18
N'4'O 98/11936 PCTIUS97/16856
27
for easier construction and assembly. The transfer device 300
also features additional or improved safety features, such as
treatment seed detection circuit and display, a fluid pressure
indicator/relief valve, and a catheter connector/seed or pin
.5 gate interlock, all of which are described in greater detail
below.
Turning to the exploded view of Fig. 31, it can be seen
that the transfer device comprises a two-part shell, including
shell halves 302a and 302b which enclose a chassis 304, on
which the various components of the transfer device 300 are
mounted. The shell half 302a includes a magnifying window 306
for viewing the quartz sleeve or housing 308 having a lumen
308a that holds the treatment seeds (not shown), indicator
lights or "annunciators" comprising LEDs 310a and 310b (Fig.
30) that indicate whether the treatment seeds are residing in
the quartz sleeve or elsewhere in the transfer device and its
associated catheter, a power button 312 for activating the LED
seed detection/indicator system, a pressure indicator window
314 for providing a visual indication of the fluid pressure
within the treatment system, and a fluid control button 316
(similar in function to fluid control handle 44 or 228
described above) for actuating the fluid control switch.
Along the side of the housing shell half 302a are a release
button 318 for the catheter connector (similar in function to
the release button 168 described above), and a sliding gate
actuator switch 320 that covers the release button 318 to
prevent the unintentional release of the catheter connector
when the treatment seeds are being transferred to or are
inside of the catheter. The transfer device 300_also includes
a compartment 319 at its proximal end (Fig. 33) for receiving
a fluid collection bag (not shown).
Turning to Figs. 29A and B, the transfer device 300 is
shown with a detachable syringe 322 which provides the
pressurized fluid for hydraulic delivery and retrieval of the
treatment seeds used in the system. The syringe 322 is
CA 02577174 2008-08-18
WO 98/11936 1'CT/US97116856
28
connected to the transfer device by a luer lock 324 and is
supported on the transfer device by a saddle having two off-
set arms 326a and 326b (best seen in Figs. 30 and 31) that
extend from shell halves 302a and 302b, respectively, and wrap
around the barrel 322a of the syringe 322 to firmly hold the
syringe to the transfer device. As can be seen in Figs. 29A
and B, the syringe 322 is held at an angle from the
longitudinal axis of the transfer device to permit easier
manipulation of the syringe plunger 322b.
As indicated above, the interior components of the
transfer device 300 are constructed separately and are mounted
to the chassis 304, where they are preferably joined together
for fluid communication by means of polyethylene tubing (not
shown) and barbed connectors such as, e.g., 328 (Fig. 31).
This type of construction may permit simpler and more
economical construction and assembly of the transfer device
than the previously described embodiments in which, e.g., the
various housing members (and their respective fluid
passageways) and the fluid control switch are machined from
blocks of solid material that have to be joined together. For
example, the fluid control switch 330 of the transfer device
300 may comprise a standard four port valve body, such as
valve model no. 7017KV, manufactured by the Kloehn Co. of
Brea, California, rather than the custom-machined switches 44
(Figs. 1, 2, 6, 7) or 210 (Figs. 21B, 24-27) and their
respective interfitting rear housing members 18, 200.
With reference to Figs. 29B, 31, and 37, the chassis 304
of the transfer device 300 also supports a pressure
indicator/pressure relief valve, generally indicated by 332,
that is visible through the pressure indicator window 314 on
shell half 302a. The pressure indicator/relief valve 332 is
in fluid communication with the syringe 332 and is designed to
provide an easily-readable visual indication of the relative
fluid pressure in the treatment system and to release the
fluid to the reservoir when it exceeds a predetermined maximum
CA 02577174 2008-08-18
WO 98/11936 PCT/i;S97/16856
29
valve (e.g., 100 psi), thus insuring that the fluid pressure
does not attain a level that could possibly damage either the
transfer device or its associated catheter.
With reference to Figs. 35A-D, the pressure
indicator/relief valve comprises a cylinder 334 with having an
inlet port 336 in fluid communication with the syringe 322.
The cylinder 334 has a graduated inside diameter, the smaller-
diameter portion 338a, being, e.g., .375 in., and the larger
diameter portion 338b being, e.g., .399 in. (Figs. 35A and B).
The cylinder 334 houses a piston 340 sized to fit in the
smaller diameter portion 338a of the cylinder 334, and a
spring 342 is interposed between the piston 340 and the end
wall of the larger diameter portion 338b of the cylinder. The
spring 342 has a spring constant and length selected to
maintain the piston 340 in smaller-diameter portion 338a of
the cylinder 334 until the fluid pressure reaches the
predetermined maximum. When the spring 342 is sufficiently
compressed by the fluid pressure to permit the piston 340 to
move into the larger-diameter portion 338b of the cylinder 334
(i.e., when the pressure reaches 100 psi), fluid passes around
the piston into the larger-diameter portion 338b of the
cylinder and exits through an outlet 344 that is in fluid
communication with larger-diameter portion 338b of the
cylinder. Once the fluid pressure in the system is below-the
predetermined maximum, the spring 342 biases the piston 340
back into the smaller diameter portion 338a of the cylinder.
As presently contemplated, the piston 340 comprises two
parts 340a and 340b that interfit to create a relieved
interface which seats a seal (not shown) that maintains fluid-
tight contact between the piston 340 and the smaller-diameter
portion 338a of the cylinder 334. The piston may be
manufactured of a white Delrin material and the seal may be a
ring seal, such as that manufactured by Bal Seal Engineering
Company of Santa Ana, California under part no. 410 MB-010-G-
316. The cylinder 334 may be made of a clear polycarbonate,
CA 02577174 2008-08-18
\N'O 98/11936 PCTIUS97/16856
having a polished inside diameter and graduation markings (not
shown) on the outside thereof which are visible through the
pressure indicator window 314. The graduation markings permit
the user to have a visual indication of the fluid pressure in
5 the system based upon the relative position of the piston 340
within the cylinder 334. Further, the spring 342 is
preferably stainless steel, such as that manufactured by the
Lee Spring Company of Brooklyn, New York having a stock no. of
LCM-110E-13-S, standard series. Of course, various other
10 pressure gauges and relief valves as are well-known in the art
may be utilized in place of the spring-loaded piston and
cylinder arrangement described above.
Like the above-described embodiments, the transfer device
300 also includes a release trigger/release switch mechanism
15 350 (Fig. 31) for receiving and locking the catheter connector
into the transfer device (similar in appearance and operation
to the release trigger 172/release switch 170 described above
and shown in Figs. 16-19). The transfer device 300 further
includes a pin gate 352 distal of the quartz seed sleeve 308
20 that blocks the seed lumen to prevent treatment seeds from
exiting the transfer device, while still permitting fluid to
flow through the seed lumen for, e.g., priming the system.
However, the transfer device 300 includes a safety interlock
between the release trigger/release switch 350 and the pin
25 gate 352, generally indicated by 354 (best seen in Fig. 40A)
that prevents the release switch from being depressed (and
thus preventing the user from removing the catheter connector
from the transfer device) if the pin gate is retracted to a
position that permits treatment seeds to pass through the seed
30 lumen.
Turning to Figs. 29B, 31, 32B and 32C, there is seen a
separate block member 356 that supports on the chassis 304 the
release trigger/release switch mechanism 350 and pin gate
mechanism 352, generally described above, as well as the
quartz sleeve 308 and seed verification system (which is
CA 02577174 2008-08-18
,=
31
described in greater detail below). Similar to the release
switch 170 described above, the release switch 358 (Fig. 38)
includes a body portion 358a, preferably made of a Delrin
material, with a curved and notched ramp 358b at one end, and
the release button 318 secured by a screw 360 (Fig. 31) at the
opposite end. Alternatively, the release button 318 may be an
integral part of the release switch 358. As described above
in connection with release switch 170 and release trigger 172,
the curved and notched ramp 358b of release switch 358 engages
a circumferentially relieved section 362 on the catheter
connector 364 (Fig. 41) to lock the connector into the
transfer device. The release switch 358 is depressed to
disengage the curved and notched ramp 358b from the catheter
connector 364 to permit removal of the connector from the
transfer device.
As illustrated, the pin gate 352 (Figs. 39A, B) is
preferably made of stainless steel and has a T-configuration
comprising a separate enlarged body 352a that terminates in a
slender cylindrical elongated member 352b. A transverse head
352c is supported by the body portion 352b of the pin gate
352. The elongated member 352b of the pin gate 352 has a
diameter that is less than the diameter of the seed lumen, so
that when interposed through the seed lumen it will block
passage of treatment seeds, but allow fluid to pass.
The pin gate 352 is actuated by means of a slider block
366 which is received in an elongated slot 368 (Fig. 31) in
the block member 356 and is manipulated by the gate actuator
switch 320. With reference to Fig. 40B, the slider block 366
includes two generally L-shaped legs 370a and 370b connected
to the proximal end of the slider block, with the free ends of
the legs forming a ramp that engages the transverse head 352c
of the pin gate 352 (best seen in Fig. 32c) to move the pin
gate out of the seed lumen when the slider block 366 is moved
in a proximal to distal direction. The legs 370a, 370b
::5 straddle a guide track 372 (Fig. 32A) forrr~ed in the block
CA 02577174 2008-08-18
NN70 98/11936 PCT/US97/16856
32
member 356. A pivoting lock 374 (Figs. 32C, 40A and 40C) is
biased by a spring steel (24 GA) leaf spring 376 to urge the
transverse head 352c of the gate pin 352 down the ramp formed
by the legs 370a and b when the slider block 366 is moved in
a distal to proximal direction, thus causing the pin gate 362
to block the seed lumen. The leaf spring 376 is preferably
supported on a block 378 that is secured to the block member
356 by two screws 380 received in tapped holes in the block
member 356. It is contemplated that each of the slider block
366, pivoting lock 374 and block 378 will be made of aluninum.
In keeping with the invention, an interlock mechanism is
provided between the release switch 358 and the slider block
366. Specifically, the distal end of the slider block 366
includes a extending shaft 382 that prevents the slider block
366 from moving in a proximal to distal direction to retract
the pin gate 352 unless the shaft 382 is aligned with a
through-hole 358c in the body portion 358a of the release
switch 358. (A similar shaft 384 extends from the proximal
side of the slider block 366 to limit motion of the slider
block in a distal to proximal direction.) However, the
through-hole 358c only aligns with the shaft 382 when the
catheter is connected to the transfer device and the curved
and notched ramp 358b on the release switch 358 engages the
relieved section 362 of the catheter connector 364. Thus, the
pin gate 352 cannot be retracted by the slider block 366
unless the catheter is connected to the transfer device to
align the through-hole 358c with the shaft 382. In addition,
when the shaft 382 extends through the hole 358c, the release
switch 358 cannot be depressed, thus preventing the release
switch 358 from disengaging the relieved section 362 on the
catheter connector. Accordingly, the catheter cannot be
released by the transfer device if the pin gate is retracted.
As an added safety feature, the gate actuator switch 320 is
configured to at least partially cover the release button 318
CA 02577174 2008-08-18
33
on the release switch 358 when the pin gate 352 is retracted
(best seen in Fig. 32C), thus preventing the release button
318 from being depressed.
In keeping with a further aspect of the invention, the
catheter connector 364 is provided with a detent that
interlocks with the transfer device 300 that must be manually
actuated simultaneously with depressing the release button 318
to release the catheter connector 364 from the transfer
device. This provides for added safety in that removal of the
catheter from the transfer device requires a coordinated
action of =both hands of the. operator.
Turning to Figs. 41A-C there can be seen the catheter
connector 364 which includes a central plug portion 386 having
a through lumen 388, which receives a connector insert 390
(Figs. 41E and D, described below) and a sleeve member 392
that overlies the distal portion of the connector 394a, i.e.,
that portion which remains external to the transfer device
when the connector is connected thereto. The proximal portion
of the connector 394b is received in the transfer device.
The central plug portion 386 of the connector 364
includes two integral, radially-opposed cantilever arms 396
that are connected to the distal end of the central plug 386
and extend axially along, but spaced away from, the central
plug portion. The proximal ends of the arms 396 include
transverse detent tabs 398 that, when the connector is
inserted into the transfer device, snap into contact with a
projecting shoulder 400 (Fig. 32C) in the distal end of the
transfer device, thus securing the connector in place. To
disengage the connector from the transfer -device, the
cantilever arms 396 must be depressed radially inwardly to
allow the detente tabs 398 to clear the shoulder 400.
Simultaneoiusly, the release button 318 must be depressed to
disengage the release switch 358 from the connector.
In order to prevent foreign matter from contacting the
exit of the transfer device through the slots between the
CA 02577174 2008-08-18
`VO 98/11936 PCT1US97/16856
34
cantilever arms 396 and the central'plug 386, the sleeve
member 392 is fitted over the distal end 394a of the
connector, with the proximal end of the sleeve 392 abutting
the distal end of the transfer device when the connector is
attached thereto. The sleeve member 392 is sufficiently
flexible to permit manipulation of the cantilever arms 396 to
permit removal of the catheter.
The connector insert 390 (Figs. 41E and D) has an inner
through lumen 402 which is twice stepped along the distal
portion of the insert 390. The insert 390 is molded to the
most proximal end of the catheter body 404 (seed and fluid
return lumens only) and shield tubing 406. The proximal ends
of shield tubing 406 and catheter body 404 reside within the
stepped portions of the insert 390, and a third channel 408
fluidly connects the seed lumen of the catheter with the
charnfered proximal end 410. A second bifurcation 412 occurs
within the insert so that the fluid return lumen angles away
from the seed lumen and communicates to the exterior of the
catheter connector 364 through a curved channel 414 exiting
the insert 390 and in alignment with an opening 416 in the
side wall of the catheter connector 364. The catheter
connector 364 slides over the catheter insert subassembly 418
(Fig. 42A) for positioning the insert 390 within the catheter
connector 364. The proximal end of the insert 390 is aligned
with the proximal end of the catheter connector 364 and UV
cure adhesive is injected into other openings 420 through the
connector side wall. The adhesive flows into void areas
within the catheter connector through lumen and permanently
secures the insert 390 within the catheter connector 364.
Alternatively, the catheter connector 364 can be molded over
the insert 390 after the insert has been molded to the two
lumen catheter portion.
The chamfered portion 410 of the catheter connector 364
fits over a mated projection 422 (best seen in Fig. 32C) at
the distal end of the block member 356. This fit properly
CA 02577174 2008-08-18
seats the catheter connector 364 for maximum alignment between
the connector lumen and the fluid lumen in the block member
356 and minimizes leakage of fluid at the catheter
connector/block member interface.
5 Turning to Figs. 42A-D, the catheter 424 of the present
invention is similar to the catheters discussed in the above-
identified co-pending applications. The catheter 424 has a
proximal end 426, a distal end 428, and an elongated portion
430 therebetween. As best seen in Fig. 42D, the catheter 424
10 has a seed lumen 432, a fluid return lumen 434, and a guide
wire lumen 436. The seed lumen 432 and the fluid lumen 434
are contiguous from the proximal end 394b of the catheter
connector 364 to the distal end 428 of the catheter 424 and
communicate with one another at the distal end 428 of the
15 catheter 424 through an intraluminal connector 438 (Fig. 42C)
which is located in the seed lumen 432. The intraluminal
connector 438 is preferably made of stainless steel and also
reinforces the distal end 428 of the catheter 424 to prevent
the treating elements from exiting the distal end of the
20 catheter.
The catheter 424, its seed lumen 432, and its guide wire
lumen 436 are all of a generally round cross-section as seen
in Fig. 42D. The fluid return lumen 434, however, has an
elliptical cross-section to increase the area for fluid flow
25 without compromising the outer diameter of the catheter 424.
The greater area lowers the pressure required to send
maintain, and return the treating elements. It also decreases
the time it takes to transfer the treating elements from the
transfer device 300 to the distal end 428 of the_ catheter 424
30 and vice versa. However, the fluid return lumen 434 may be of
any size or shape to provide for optimal transfer of the
treating elements using a limited volume of fluid.
For uniform dosing, it may be determined that the
treating elements need to be positioned at or near the center
35 of the luminal wall. In that case, the seed lumen 432 may
CA 02577174 2008-08-18
WO 98/11936 PCTIUS97/16856
36
need to be positioned as close as possible to the center of
the catheter 424 to prevent the seed lumen 432 and radioactive
elements from lying too close to one side of the luminal wall.
The catheter 424 is preferably made in a single extrusion
of 100% low density polyethylene which is very flexible, soft
and lubricous. These characteristics allow the catheter 424
to be inserted over a guide wire and into an endoluminal area
within the human body without damaging the luminal walls. if
a catheter 424 made of 100% low density polyethylene is too
soft or pliable, then a polyethylene blend which consists of
a certain percentage of both-high and low density polyethylene
may be used. To maintain flexibility of the catheter, the
polyethylene blend must have a higher percentage of low
density polyethylene.
Returning to Figs. 42A-C, an atraumatic tip 440 having a
small taper (preferably 11 degrees or less) and a small distal
tip radius is fused (possibly with radiofrequency energy) to
the distal end 428 of the catheter 424. The fusing process
melts the seed lumen 432 and the fluid return lumen 434
closed. The tip 440 is made of polyethylene and preferably
with ethylene vinyl acetate. The guide wire lumen 436 extends
through the tip 440 and is lined with a sleeve 442 (Fig. 42C)
of high density/low density polyethylene. This sleeve 442 is
made of a material that is of a higher durometer than the tip
440 to resist the guidewire from tearing the tip 440 as the
catheter 424 is delivered over a guidewire.
Radiopaque marker bands 444 made from platinum (900)-
iridium (10%) are located at the distal end 428 of the
catheter 424 to assist in proper placement -of both the
catheter 424 and the treating elements. The marker bands 444
are secured to and f lush with the exterior of the catheter
424. Alternatively, radiopaque markers may consist of
radiopaque ink or tiny radiopaque particles printed or blasted
onto the exterior of the catheter 424. The proximal portion
426 of the catheter may also have a depth marker (not shown)
CA 02577174 2008-08-18
37
to indicate when the catheter is near the end of the guide
wire so that the fluoroscopy can be turned on just prior to
the delivery of radiation.
The proximal end 426 of the catheter also has a
bifurcation 446 where the guide wire lumen 436 branches off
from the catheter portion 430 to a guide wire extension tubing
448. The guide wire extension 448 may include a standard luer
450 with or without a valve for preventing the patient's blood
from exiting the proximal end of the guidewire lumen 436. The
guide wire extension tubing 448 and the bifurcation 446 can be
made of polyethylene or a blend of polyethylene and ethylene
vinyl acetate. The seed lumen 432 and the fluid return lumen
434 remain contiguous throughout the bifurcation 446. Strain
relief tubing 452 is placed over the proximal end of the
catheter portion 430 and extends a short distance from the
distal end of the bifurcation 446 where it is secured. The
strain relief tubing 452 adds rigidity near the bifurcation
446 for protection from kinks or other damage to the catheter
424. Also, the shield tube 406 fits over the catheter end
proximal to the bifurcation 446 for additional protection from
the radioactive treating elements as they are transferred into
and out of the catheter 424.
At specific times during the radiation therapy procedure,
it may be necessary or desired to determine the position of
the treating elements and marker seeds with respect to the
quartz housing 308 in the transfer device 300. For example,
assuming the radiation source train comprises twelve stainless
steel encapsulated radioactive treating elements with an inert
gold marker seed at each end, the user may need to verify that
all twelve treating elements and two marker seeds are present
within the quartz housing 308 before delivery of the elements
to the distal end of the catheter 424, and for safety reasons
must be sure that all of the treating elements and marker
seeds are within the quartz housing 308 prior to closing the
CA 02577174 2008-08-18
'"O 98/11936 PCT/LS97/16856
38
pin gate 352 and disconnecting the catheter 424 from the
transfer device 300.
To determine whether or not all of the treatment elements
are within the quartz housing 308, an electronic detection
system (shown schematically in Fig. 45), which measures the
presence or non-presence of the distal gold marker seed at a
single position within the lumen 308a in the quartz housing
308, is included in the transfer device 300. The system
detects a gold marker colorimetrically by shining light of
different wavelengths onto the small area where the gold
marker should reside within the quartz housing .308 and
measuring the reflectivity. Based on the
wavelength/reflection ratios of different light, the system
determines whether a gold object (gold marker) or non-gold
object (stainless steel seed, background, or saline filled
lumen 308a in the quartz housing 308) is occupying the area.
If a gold marker seed is detected within the small area, it
would be reasonable for the user to believe that it is the
distal marker seed and that all of the elements proximal to
the distal marker seed a:rA also within the quartz housing 308.
To increase the degree of certainty that all seeds are within
the quartz housing 308, the electronic sensor can be enhanced
to determine whether or not both marker seeds are properly
positioned within the quartz housing, and/or determine
actively whether some or all stainless steel treatirig elements
are properly positioned with the quartz housing. However,
this would require providing more space within the housing of
the transfer device 300 for the additional electronic and
optical components.
In addition to detecting the absence or presence of gold
marker at a specific position along the quartz lumen 308a, the
electronics wait in a low power state for the power button 312
to be pressed. Then the two indicator LEDs 310a and 310b are
flashed on and off for several seconds after the power button
312 has been pressed to indicate that the LEDs 310a and 310b
CA 02577174 2008-08-18
4
39
and battery 454 are functional, and then indicate whether or
not a gold marker is detected by illuminating one of two
indicator LEDs 310a, 310b. A single C-cell lithium battery
454 is shown in Figs. 29B, 31, 32B and 37 for powering the
electronic system. However, the electronic system is
preferably powered by two thin batteries which are used in
series to produce +6v from a single battery pack. The output
is also inverted to produce a -6v voltage. Finally, the
electronics automatically return to the low power state after
one minute has elapsed to conserve the battery power, or
restart the one minute timing period if the button is pressed
again during that one minute.
Referring to the logic diagram shown in Fig. 45, -the
battery is indicated by 456. The power supply is controlled
by a sleep circuit. Applying power turns the sleep circuit
of f which in turn shuts down the power supply so that it draws
only enough power to keep the system alive. The on-switch 458
is a normally open push button switch 312. When the switch
458 is closed by, pressing the button 312 from the exterior of
the transfer device 300, the sleep circuit wakes up and turns
on the power supplies 460, 462, one generating +6v and the
other generating -6v. The power generated is first applied by
starting an internal timer 464 set for approximately one
minute. This internal timer 464 is an analog circuit, but can
be a digital circuit using a counter for greater precision and
longer times. At the end of.one minute the power supplies
460, 462 are turned off and the sleep circuit goes back to
sleep until the next time the switch 458 is closed. If the
button 312 is pressed during the one minute timing period, the
timing period is reset allowing the power to stay on longer
than one minute in total. The internal timer 464 can be
designed for other lengths of time. Each time the one minute
timer 464 is started, a four second test phase 466 also begins
and enables a four Hz oscillator 468 which generates a four Hz
square wave. The square wave and the four second timer are
CA 02577174 2008-08-18
--'0 98/11936 PCT/US97/16856
applied to the indicator LED drivers 470 to flash the two
indicator LEDs 310a, 310b (one is green and the other is
amber, respectively) on and off simultaneously at four Hz for
four seconds. This action informs the user that the battery
5 454 and indicator LEDs 310a, 310b are in working order. After
the four second test phase, the system goes into its normal
detection mode.
The detection mode uses the optical properties of
stainless steel (the material encapsulating the radioactive
10 isotope) and gold (the material or plated material of the
marker seeds) and the effects of red and blue light-on each
stainless steel and gold seed. The optics of the system
include a blue LED 472 employing Gallium Nitride (GaN), a red
LED 474 employing Gallium Phosphide (GaP), a photosensor 476
15 including a photo diode and integrated amplifier, a GRIN
(Graded Refractive Index) lens 478, and a second photosensor
480, which are all housed within the block member 356 that
houses the quartz sleeve 308. In Fig. 32A, the first
photosensor 476 is perpendicularly oriented with respect to
20 the quartz sleeve 308, and the blue and red LEDs 472, 474 are
oriented also at an angle on either side of the first
photosensor 476. Other orientations of the LEDs relative to
the photosensor, and orientations of the photosensor relative
to the quartz housing, may be used to increase the accuracy of
25 the electronic detection circuit. Channels 482 within the
block member 356 direct light from the LEDs 472, 474 to a
targeted location along the quartz sleeve 308 and also direct
the reflected light back to the first photosensor 476. The
GRIN lens 478, positioned between the quartz sl.eeve 308 and
30 the first photosensor 476, focuses on the quartz lumen 308a at
the site where the distal gold marker should reside when all
of the treating elements are within the quartz lumen 308a.
The GRIN lens 478 then collects light that is then directed
onto the surface of the photo diode.
CA 02577174 2008-08-18
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41
The blue and red LEDs 472, 474 used in this system supply
blue and red light in restricted wavebands that peak at 450
nanometers (nm) and 700 nanometers (nm), respectively. At 450
nm stainless steel (and tinted blue or untinted background)
has greater than 90% reflectance and gold has about 35%
reflectances; at 700nm both stainless steel and gold have
greater than 90% reflectance. This means that stainless steel
reflects blue and red light about equally well and gold
reflects well in the red light but poorly in the blue light
(gold actually absorbs the blue light). Therefore, the
measurement of the blue/red ratio of reflected l'ight can
unambiguously distinguish between a gold-colored object, in
this case a gold marker, or some other object in the
photosensor's field of view.
A clock oscillator 484 which oscillates at 3.22kHz
flashes the blue and red LEDs 472, 474 in turn (i.e., 180
degrees out of phase.) The clock oscillator 484 runs through
a flip flop 486 where its frequency is divided to create two
signals, each having a frequency of 1.61 kHz. One of the two
signals is applied to the blue LED driver 490 and the other is
applied to the red LED driver 492 so that each LED 472, 474 is
driven at approximately 1.61 kHz. Therefore, the on time and
the off time of the blue and red LEDs 472, 474 are equal, as
they take turns flashing on and off. The flashes of blue and
red light travel from the LEDs 472, 474, through channels 482
within the body, and through the quartz sleeve 308 to the
targeted location where the distal gold marker should be if
all of the seeds are within the quartz lumen 308a. If a
stainless steel seed is occupying the targeted location, then
both the red and blue light are reflected about equally well
(greater than 90%). If nothing but fluid or air fills the
quartz lumen at the targeted location, then the background, as
long as it is not tinted, also reflects both blue and red
light similarly to that of stainless steel. If a gold marker
seed is within the targeted location, then the red light is
CA 02577174 2008-08-18
= NVO 98/11936 PCTIUS97/16856
42
reflected but the blue light is absorbed. The first
photosensor 476, consisting of a photo diode and a integrated
amplifier, is optically coupled to the targeted location
within the quartz sleeve 308 by the GRIN lens 478 so that the
photosensor 476 can measure the reflected quantities of each
the blue and red lights. From this measurement, the blue/red
ratio of reflected light is used to determine the presence or
absence of a gold marker.
The viewing window 306 along the top 302a of the transfer
device 300 allows ambient light to also be reflected off of
the object within the field of view of the photosensor.476.
The photosensor 476 will most likely detect the ambient light
in addition to the red and blue light. The signal of the
ambient light may adversely affect the output of the
photosensor 476. The photosensor 476 must be operational even
with light coming in through the transparent viewing.window.
Therefore, the signals due to ambient light sources must be
removed from the system. This is done by using a high pass
filter 493 which is followed by synchronous detector 494
followed by a low pass,filter 496. The synchronous detector
494 is a circuit which is synchronized with the blue and red
LED pulses. The synchronous detector 494 removes all. AC
signals except for those attributable to the blue and red LEDs
472, 474. The low pass filter 496 converts the AC
(alternating current) output from the photosensor 476 to a DC
(direct current) voltage because the system relies upon the
differences between the red and blue signals. A blanking
circuit is also included to isolate the low-pass filters for
a brief period following each clock transition to improve the
accuracy of the low-pass filtered signals. The amplitudes of
those signals correspond to how much light is being reflected
from the targeted location and the DC voltage is proportional
to the blue/red ratio of reflective light. The circuit is
adjusted so that, in the case of gold being present at the
targeted location, the DC voltage output is zero. In the case
CA 02577174 2008-08-18
=
43
of any other object present at the targeted location, the
output is a non-null voltage.
The system is designed to produce a null voltage with the
detection of gold (and a non-zero voltage with the detection
of stainless steel or background) because a null signal is
unaffected by any gains encountered along the signal path
(zero times any magnitude is always zero); thus, the null
signal is much less likely to go outside the tolerance window
created around the reference voltage to be detected (null).
Because the null signal is less affected by variations within
the system, such as mechanical tolerances and temperature
changes, it is much more reliable than a non-null voltage.
The gold should produce the null because it is the single
state that must be distinguished from all others. The only
adjustment needed for making the output voltage zero when a
gold marker occupies the targeted location is adjusting the
intensity with which the blue LED 472 illuminates. Without
that adjustment, stainless steel will produce the null because
it reflects the blue and red light equally and produces
signals close to the same amplitude when the intensity with
which the blue and red LEDs 472, 474 illuminate are equal.
Two electrical signals of the same amplitude produce zero
volts. Conversely, because gold reflects red and absorbs blue
when the blue and red LEDs 472, 474 illuminate with the same
intensity, the photosensor 476 sends out signals of different
amplitudes (high signal for red and low signal for blue) which
are converted to a non-null DC voltage. In order for the
presence of gold to produce a null, gold, not stainless steel,
must produce equal amounts of reflection for both_ the blue and
red lights. This is done by increasing the drive of the blue
LED 472 relative to the drive of the red LED 474 so that the
blue LED 472 illuminates with greater intensity than the red
LED 474. Now gold equally reflects the blue and red lights
which produces no AC signal from the photosensor 476, thus,
creating a null. On the other hand, the reflection of
CA 02577174 2008-08-18
'LO 98/11936 PCT/US97/16856
44
stainless steel is brighter with the blue because of the boost
given to the blue LED driver 490. Therefore, the blue signal
is larger than the red signal and the resulting square wave
produces a non-zero DC voltage. To make sure the stainless
steel treating elements and the background always produce a
non-null output voltage, they should be untinted or tinted
blue so as to reflect blue and absorb red which is the
opposite of what gold does.
When the DC signal is at zero volts, the system will
indicate the detection of gold. In practice, however, due to
certain variations within the system, the DC signal will
almost never read exactly zero volts. Therefore, a window
detector 498 with an upper limit reference voltage and a lower
limit reference voltage creates a band that is centered on
zero. The window detector 498 receives the DC signal and
determines whether or not it lies within the set band (for
example: -11 to +11 millivolts). If the signal lies within
the band, then the window detector decides that the signal is
consistent with the presence of gold. The width of the window
can be changed in order to vary the tolerance of the system to
errors (smaller width for tighter tolerances). After the
signal goes through the window detector, the decoded signal
enters the two drivers for the indicator LEDs 310a, 310b. If
the decoded signal indicates that gold is present, then the,
green LED 310a along the top 302a of the transfer device 300
is illuminated, displaying to the user that all of the
treating elements are within the quartz housing 308; and if
the decoded signal indicates that gold is not present, then
the amber LED 310b along the top 302a of the transfer device
300 is illuminated, displaying to the user that not all of the
treating elements are within the quartz housing 308.
Both the blue and red LEDs 472, 474 are temperature
sensitive and their outputs are affected by other factors,
such as aging, level of current drive, and possibly ionizing
radiation. In particular, the output of the red LED 474
CA 02577174 2008-08-18
significantly decreases as the temperature rises and
significantly increases as the temperature drops. These
temperature induced changes in the output of the red LED 474
will disturb the blue/red ratio of reflected light and may
5 hinder the system's ability to detect the presence of gold.
To stabilize the output of the red LED 474, a brightness
control loop is included to regulate the output and compensate
for any temperature effects so as to hold the output of the
red LED 474 constant. The blue LED 472, however, is
10 sufficiently temperature stable over the normal operating
temperature range of +10 C to +35 C. Therefore, no brightness
control loop is necessary for the blue LED 472. The red LED
brightness control loop incorporates the second photosensor
480. The second photosensor 480 compensates for the
15 temperature induced changes in the output of the red LED 474
by "staring" at the tip of the red LED 474 only and measuring
how much light it is generating. To best measure the output,
the second photosensor 480 is positioned at a 900 angle with
respect to the longitudinal axis of the red LED 474. The
20 output signal of the red LED 474 is detected in the same way
as the blue/red reflective signal by flowing through the
synchronous detector 500a and high and low pass filters 502c,
504a. The outcoming signal then passes through the inverting
DC amplifier 506a which sets the control loop gain. The
25 signal provides negative gain to the reference signal
(RED_REF) 508c that sets the red LED drive range. The
adjusted signal entering the red LED driver 492 attempts to
maintain the output of the red LED 474 constant even though
the actual amount of light for any given current may be trying
30 to change. This is a very simple control loop; other
architectures known to those skilled in the art may be used in
its place. -A control loop could be added to the blue LED also
to improve the stability of its output.
Circuit diagrams corresponding to the logic diagram of
35 Fig. 45 are shown in Figs. 45A-C. Figure 46B displays a one
CA 02577174 2008-08-18
=
.:: N'O 98/11936 PCT/US97116856
46
minute timer, a +5 power supply and a -5 power supply. Figs.
46C-1, C-2, and C-3 displays three circuits: a +2.5 reference
voltage; processes for the blue signal; and processes for the
red signal. Figs. 46A-1 and A-2 display two LED current
drivers, a blanking circuit, a 3 kHz oscillator, a 4 kHz
clock, a 4 second timer, a window detector and window
threshold. These schematics display each component of the
electronics and how they interrelate within the electronic
system. A specific layout is shown. Other components or
layouts which produce the same outcome may be used. The
circuits are printed on boards 510a, 512a (Fig. 31) -that are
mounted to the chassis 304 of the transfer device 300.
As a backup to the electronic source detection system,
the window 306 above the quartz housing allows the user of the
1s transfer device 300 to visually detect whether or not all of
the treating elements are within the quartz sleeve 308 by
either detecting the presence of each marker seed on either
side of the treating elements or by counting the number of
treating elements and marker seeds within the quartz sleeve
308. To assist the user with visual detection, a magnifying
lens 514a (Fig. 32A) is secured to the top portion of the body
302a where it is situated directly above the quartz lumen
308a. The magnifying lens 514a is also located above the
indicator LEDs 310a, 310b so that they are also magnified..
Turning to Figures 47-51C, there is seen a further
improved transfer device 500 of the catheter based radiation
delivery system of the present invention. Similar to transfer
device 300, transfer device 500 has an exterior which is
ergonomically designed to be easily handled by_the user and
has internal components which include a pressure indicator,
pressure relief valve, flow control valve and pathways, quartz
housing, a catheter connector/pin gate interlock system, and
a treatment element electronic detection system. The i,:proved
versions of these and other components, as well as additional
features incorporated into transfer device 500 for additional
CA 02577174 2008-08-18
A'O 98/11936 PCTIUS97/16856
47
safety and user feedback, are all described in greater detail
below.
As seen in the exploded view of Figure 50, the exterior
of the transfer device 500 is made up of an upper portion 502a
and a lower portion 502b, each portion comprising a shell
half. The two shell halves 502a, 502b fit together to enclose
a chassis 504, on which the components of the transfer device
500 are mounted. Openings in the upper shell half 502a allow
user access to a power button 506 for activating the
electronic detection system and indicator lights 508a, 508b,
and a fluid control switch 510 for activating the fluid
control valve 512 (Figure 47). The upper shell portion 502a
also includes a pressure indicator window 514, and a
magnifying window 516 for viewing the indicator lights 508a
and 508b, the quartz sleeve 518 where the treatment elements
and marker seeds are stored, and the distal passageways 523
leading from the quartz sleeve 518 to the distal opening 524
of the transfer device 500. The two shell halves 508a and
508b together create openings along the sides of the transfer
device 500 that allow access to a fluid entry port 526, a
sliding gate actuator switch 528 and either end of a latch
mechanism 586 for the catheter connector. Together, the two
shell halves 508a and 508b also create an opening 524 (Figure
49) at the distal end of the transfer device 500 for entry-of
the catheter connector and an opening at the proximal end of
the transfer device 500 allowing access to a fluid exit port
530, which preferably does not extend much, if at all, beyond
the exterior wall of the transfer device 500. A compartment
for storing a fluid collection bag (described inxelation with
transfer device 300) may be eliminated to create space inside
the transfer device 500 for internal components. Instead a
clip may be added to the bottom of the transfer device 500 to
secure a fluid collection bag (not shown). Polyurethane is an
example of a material that can be used to make the two shell
halves 508a and 508b.
CA 02577174 2008-08-18
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VO 98/11936 PCT/US97/16856
48
The transfer device 500 has a fluid entry port 526 to
which a source of pressurized fluid (liquid or gas), such as
a fluid filled syringe or automatic fluid pump, is connected
for hydraulic or pneumatic delivery and retrieval of treatment
elements. The fluid entry port 526 as shown in Figure 51A has
a luer connector. Two offset arms 532a and 532b similar to
support arms 326a, 326b described above in connection with
transfer device 300 extend from the shell portions 502a and
502b to support and orient a syringe 534a along side transfer
device 500 at predetermined angles with respect to its
longitudinal axis to afford easier manipulation of the syringe
plunger 534b and proper alignment between the distal end of
the syringe 534a and the fluid entry port 526. As depicted in
Figure 48, the syringe 534a is angled outwardly approximately
seven degrees and upwardly approximately twenty-five degrees
with respect to the longitudinal plane of the transfer device
500. The support arms 532a and 532b (Figures 47 and 49) are
configured such that the arm 532a extending from the upper
shell portion is proximal to the arm 532b of the lower shell
portion, thus providing a clearer site line between the
proximal end of the transfer device 500 and the fluid access
526 port for quick and easy connection of the syringe 534a.
With reference to Figures 50-51B and 52, the chassis of
transfer device 500 also supports a pressure indicator 536 and
a pressure relief valve 538 that work independently from one
another. The pressure indicator 536 assists the user in
determining the appropriate pressures necessary to send and
retrieve treatment elements to and from the distal end of the
catheter and to maintain the treatment elements at the distal
end of the catheter during treatment. The pressure relief
valve 538 prevents overpressurization of the system which
could damage the catheter and/or the transfer device 500.
The pressure indicator 536 comprises a hollow cylinder
540 having an inlet port 542 in fluid communication with the
fluid source at one end and an end plug 544 at the other end.
CA 02577174 2008-08-18
49
The cylinder 540 houses a piston 546 and a compression spring
548 residing between the piston 546 and the end plug 544. The
piston 546 may be a ring seal as described above in connection
with transfer device 300, a rubber plunger obtained from a
syringe, or a piston of a harder material with o-ring grooves
accommodating o-rings such that they create a seal with the
cylinder inside wall. The spring 548 is preferably stainless
steel, such as a spring having part number C0300-032-18
manufactured by Mid-West Express Company. The compression
spring 548 used must have a spring rate (i.e., the amount of
deflection per unit force) that biases the piston 546 to a
-specific position along the pressure indicator window 514 for
the system operating pressures (0 to 100 15 psi). The
pressure inside the transfer device 500, created by the fluid
source, moves the piston 546 in the cylinder 540 such that it
compresses the spring 548 and forces the air on the other side
of the piston to escape through a vent opening in the end
plug 544. The seal created by the piston 546 about the
periphery of the cylinder's inside wall keeps the fluid from
passing by the piston 546. As seen in Figure 47, the piston
546 accommodates a piston ring 550 which is highly visible
through the pressure_ indicator window 514. The piston ring
550 not only serves as the pressure marker but also provides
some rigidity along the central portion of the piston 546.
Additionally, a background material may be provided along the
bottom of the cylinder 540 so as to block the view of other
components which may interfere with the visibility of the
piston 546 and piston ring 550. However, other standard
pressure gauges may be used in place of the spring-loaded
piston and cylinder arrangements described above.
Lettering and/or markings 554 are placed on the exterior
of the transfer device 500 next to the pressure indicator
window 514 to indicate where the piston ring 550 should reside
within the pressure indicator window 514 to provide the
CA 02577174 2008-08-18
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appropriate pressure for transferring the treatment elements
to and from the catheter and to indicate where the piston ring
550 should reside to provide the appropriate pressure for
maintaining the treatment elements at the distal end of the
5 catheter for the duration of the treatment. The pressure for
maintaining the treatment elements at the distal end of the
catheter is much less than the pressure required to quickly
send and retrieve the treatment elements. Both the pressure
indicator 536 and the pressure relief valve 538 are retained
10 by an L-shaped block portion 556 that is mounted to the
chassis 504.
The pressure relief valve 538 is a standard valve with an
activation pressure of 100 15 psi. Such a valve is that
having part number PCRM0000001S, manufactured by The Lee
15 Company of Westbrook, Connecticut. The pressure relief valve
538 comprises a pin, a ball, a spring, and a spring retainer
and is press fitted into a pressure relief valve housing 558.
Each end of the pressure relief housing 558 mates with a fluid
connector 559 System pressure above 100 15 psi is forceful
20 enough to unseat the spring biased ball and allow the fluid to
flow through the valve 538 and exit the transfer device 500
through the fluid exit port 530 into an external fluid
reservoir (not shown). Otherwise, the spring biases the ball
into a seated position therebyblocking flow through the valve'
25 538 and allowing flow to continue to be safely directed
through the system.
The,appearance and functionality of fluid control valve
512 are identical to that of fluid control valve 330 in Figure
31. The fluid control valve 512 of the present transfer
30 device 500 directs the fluid flow of the system which can be
manipulated by toggling the flow control switch 510 between
detented send, return, and neutral positions. The valve 512
may comprise four ports 562 and should be capable of
withstanding the system's highest operating pressure (i.e. at
CA 02577174 2008-08-18
= ,.., _ . 51
least 100 to' 115 psi), such as valve part no. 0162336 (HV4-4,
w/.040 ports), manufactured by the Hamilton Company of Reno,
Nevada.
As indicated above, the interior components of the
transfer device 500 are constructed separately and mounted to
the chassis, where they are joined together for fluid
communication by means of tubing (not shown) and barbed
connectors, such as 542 shown in Figure 52. Figure 53 is a
flow control diagram that visually explains fluid flow of the
system.
Turning to Figures 48 and 50-51C, the transfer device 500
further includes a separate block member 564 which is mounted
to the chassis 504 and houses the quartz sleeve 518, a pin
gate mechanism 576, and the optics portion of a seed
verification system. As an improvement to the block member 564
described earlier in connection with transfer device 300, the
present block member 564 has a mated projection 566 that is
machined below the surface of the block member 564 such that
it is recessed within a cavity 568. This simplified design
reduces the number of components by allowing an o-ring groove
570 to be cut directly into the block member cavity 568 wall
surrounding the mated projection 566.
The block member 564 may contain a spring loaded assembly
(not shown) to hold the quartz sleeve 518 in its proper
position (in alignment with the optics for proper seed
detection) even when the transfer device 500 is dropped. A
lumen 572 extends along the length of the quartz sleeve 518
for storage of the treatment elements and marker seeds when
they are not being used to deliver radiation therapy. The
quartz sleeve 518 shields the user from beta particles emitted
by the treatment elements when stored therein, thus enabling
a user to safely handle the transfer device 500. The distal
end of the quartz lumen 572 preferably has a chamfer to
prevent seed hang-ups when transferring them. As described
previously, the entire length of the quartz sleeve 518 can be
CA 02577174 2008-08-18
-`30 98/11936 PCT/US97/16856
52
seen through an opening in the block me;riber 564 which is
aligned with the viewing window 516. To provide better
visibility of the treatment elements and marker seeds within
the quartz sleeve 518, a colored material (preferably white)
may be adhered to or placed under the bottom of the quartz
sleeve.
The pin gate mechanism 576 consists of a pin gate 578a,
cylindrical pin head 578b, slider block 580, pivoting lock
582, leaf spring 584a, and leaf spring block 584b all working
together to position the pin gate 578a in an extended (closed)
or retracted (open) position relative to the lumen 523 just
distal of the quartz sleeve 518 for respectively blocking or
permitting passage of treatment elements. The components and
functions of the pin gate mechanism 576 are identical to that
of pin gate mechanism 352 described above in connection with
transfer device 300. However, the pin gate mechanism 576 of
the present invention provides an additional safety feature
for preventing the pin gate 578a from closing onto and
damaging a treatment element. If an attempt to close the pin
gate 578a is made while a treatment element is in the pathway
of the pin gate 578a, the pivoting lock 582 is oriented, in
such a way that it does not clear the pathway of the moving
slider and prevents any further advancement of the slider,
which in turn halts the downward motion of the pin onto the,
treatment element. Additionally, the pin gate mechanism 576
may be positioned such that the pin gate 578a is extended and
retracted into the distal end of the quartz lumen 572 through
a radial channel extending from the top of the quartz sleeve
518 and intersecting with the quartz lumen 572.
In place of a release trigger/release switch mechanism
350 (shown in Figure 38), the present transfer device 500
includes a latch mechanism 586 (shown in Figures 48, 51A, and
54A-56C) for receiving, locking, and properly seating the
catheter connector in the transfer device. The components of
the latch mechanism 586 include a latch body 590, a latch sear
CA 02577174 2008-08-18
53
592, a latch button 594, and two ball and spring plungers 596,
all of which reside in between the block member 564 and end
body 598 of the transfer device 500. As illustrated in
Figures 54A-B and 56B, the latch body 590 is generally
rectangular with an elongated opening as seen from its distal
face and a raised portion with a U-shaped recess as seen on
its proximal face. The U-shaped recess is adjacent to the
elongated opening, extends partially along the opening's
length, and is accessible therethrough. Because the U-shaped
recess is smaller than the elongated opening, some of the
raised U-shaped portion 600 surrounding the recess overlaps a
portion of the elongated opening. The latch body 590 is
preferably made from an opaque material (such as Delrin) to
provide lubricity between it and the polycarbonate pieces
(i.e. block portion 564 and end body 598) with which it will
be in sliding contact. The latch sear 592 (Figures 55 and
56B-C) fits within a similarly shaped recessed portion along
the proximal face of the latch body 590 such that the small
end 606 of the latch sear 592 extends within the elongated
opening (Figure 56B). The latch button 594 houses a
compression spring 608 and slides over the upper ends 610 and
612 of the latch sear 592 and latch body 590 such that the
latch sear 592 and compression spring 608 are in contact with
one another and the latch button 594 is secured to the latch
body 590. The ball and spring plungers 596 (Figure 50) extend
from shallow bores within the end body 598 such that each of
the two balls rests within one of the valleys 614 along the
proximal face of the latch body 590 in between the elongated
opening and the extended portion with the through hole.
As a catheter connector 588 is being inserted into the
transfer device 500, the distal end of the connector 588
passes through the unobstructed half of the elongated opening
of the latch body 590 and seats itself on the mated projection
566 extending from the block member 564 (Figures 51A-B). To
CA 02577174 2008-08-18
= . 54
lock the connector 588 into the transfer device 500, the latch
button 594 is pressed inward to facilitate engagement of the
relieved section of the connector 588 with the U-shaped
portion 600 that overlaps the elongated opening in the latch
body 590. As the latch body 590 is moved from the unlatched
position to the latched position, the ball of each of the two
ball and spring plungers 596 is ramped onto one of the peaks
616 adjacent the valleys 614 on the proximal face of the latch
body. This ramping causes the spring biased plungers 596 to
compress and force the latch body 590 and engaged connector
588 toward the mated projection 566 at the distal end of the
block member 664; thus, ensuring that the chamfer 618 of the
connector insert 632 is completely seated against =the
projection 566 and in complete alignment with its opening. As
an indication that the connector 588 has been fully engaged,
the free end 620 of the latch body 590 (opposite that end
connected to the latch button 594) pops out from the side of
the transfer device 500 (Figures 47, 48, and 51A). If a band
622 or other marking on the free end 620 is fully visible,
then the user can be sure that the connector 588 is now locked
into the transfer device 500. To disengage the connector 588
from the transfer device 500, the free end 620 of the latch
body 590 is pushed inward to remove the U-shaped portion from
the relieved area of the connector 588.
To provide a safer transfer device, an interlock
mechanism exists between the latch body 590 and the slider
block 580 as can be seen in Figures 48 and 51A . The slider
block 580 slides toward the distal end of the transfer device
500 to retract the pin gate 578a and thus, allow the treatment
elements to be delivered out of the transfer device 500. To
enable this movement, the shaft 581 extending from the distal
end of the slider block 580 and the through holes of the
latch buttbn 594, latch sear 592, and latch body 590 must all
be in alignment. When the latching mechanism 586 is in the
unlatched position, regardless of whether cr not a connector
CA 02577174 2008-08-18
588 is inserted into the transfer device 500, the extending
shaft 581 does not align with the through holes and
additionally, the actuator switch 528 is impeded by the popped
up latch button 594. When the latching mechanism 586 is in
5 the latched position and no connector 588 is locked into the
transfer device 500, the through hole in the latch sear 592
does not completely align with the through hole in-the latch
= -button 594 and movement of the slider block 580 is impeded by
the latch sear 592. However, when the connector 588 is
10 inserted into the transfer device 500 and the latch body 590
is slid toward the connector 588.for engagement purposes, the
small end 606 of latch sear 592 collides with the connector
588 just above the connector's relieved portion 589 and is
forced toward the latch button 594 and against the spring 608
15 such that the sear's through hole now aligns with both the
latch body through hole and the latch button through hole.
Thus, the pin gate 578a can only be retracted to an open gate
position when the connector 588 is inserted into the transfer
device 500 and fully engaged by the latching mechanism 586.
20 Furthermore, when the necessary conditions are met and the
shaft 581 extends through all three holes as seen in Figure
51A, the latch body-590 cannot be slid back to the unlatched
position, thus preventing the latch body 590 from disengaging
the relieved portion 589 on the connector 588 . As an extra
25 safety caution and a visual reminder to the user that the
connector 588 is not to be disengaged from the transfer device
500 while the pin gate 578a is in a retracted position, the
actuator switch 528 is configured to at least partially cover
the latch button 594, thus preventing'the latch body 590 from
30 being moved into the unlatched position.
Turning to Figures 57A-58A and 57C, the catheter
connector 588, which is a part of the present invention, is
provided with detents 626 that interlock with an annular
shoulder in the end body 598 of the transfer device 500 and
CA 02577174 2008-08-18
,\VO 98/11936 PCT/US97/16856
56
must be manually actuated to withdraw the catheter connector
588 from the transfer device 500 after it has been unlatched
by the latching mechanism 586. The catheter connector 588
includes a central plug portion 630 having a through lumen 630
and cantilever arms 634, a connector insert 632 which is
received by central plug through lumen 630, and a skirt 636
that fits over the distal portion of the connector 588 that
-remains outside of the transfer device 500 when the connector
588 is fully connected thereto. The connector insert 632 is
identical to the connector insert 390 described above and
shown in Figures 41E and D. The.central plug portion. 628 may
be identical to the one described above and.shown in Figures
4C and D or may be slightly different by having the wall
between the two-o-rings taper inward from both ends to enhance
the sealing effects of the o-rings. The skirt 636 57A-
(Figures 57A-B and 58A) is threaded over the catheter tubing
and then after the connector 588 is bonded to the catheter
tubing, it is fitted over a distal portion of the connector
588 which includes the cantilever arms 634. When the
20- connector 588 is fully inserted into the transfer device 500,
the :.skirt 636 covers the slotted portions 642 that remain
external to the transfer device. 500, abuts the distal tip of
the transfer device 500, and surrounds the connector entrance
524 to the transfer device 500. These characteristics of the
skirt 636 serve to maintain sterility of the distal portion
of the connector 588 as well as prevent foreign matter from
contacting the connector entrance to the transfer device 500
through the slotted portions 642 of the central plug 630. As
shown in Figure 57A, -the skirt 636 preferably has two
opposing rectangular sides 645 for mating with the depressable
sides of the cantilever arms 634 and for indicating to the
user where to manipulate the cantilever arms 634. The skirt
636 is preferably made of silicone or other material that is
flexible enough to permit manipulation of the=cantilever arms
636 as the connector 588 is pulled out of the transfer device
CA 02577174 2008-08-18
_ 57
500. In addition, the rectangular sides 645 may be thinner
than the rest of skirt 636 so as to provide for easier
manipulation of the cantilever arms 634. Having to depress
the arms 634 while simultaneously pulling on the connector 588
is another safety feature for preventing inadvertent
withdrawal of the connector 588 from the transfer device 500.
As seen in Figure 58A, catheter 647 of the present
invention connects to the transfer device 300, 500 by catheter
connector 588 to permit delivery of the treatment elements to
a selected site within a patient. With reference to Figures
58A-C, the catheter 647 and its components (except for the
catheter connector as described just previously) are identical
to that shown in Figures 42A-42D. However, the most distal
marker band of the present invention is in closer proximity to
the proximal end of the intraluminal connector 646 the
intraluminal connector 646 at the distal end of the catheter
647 may be made of platinum/iridium so as to be visible under
fluoroscopy and possibly eliminate the need for the distal
marker band 652. Also, the catheter fluid lumens 648 and 650
(especially the fluid return lumen 650) shall have dimensions
suitable for transmitting hydraulic or pneumatic pressure for
movement of the treatment elements within three to ten seconds
are preferably dimensioned to provide treatment element send
and return times each in the range of three to ten seconds and
more preferably within two to six seconds, while not exceeding
a 5 French outer catheter diameter, not exceeding a pressure
of 100 psi, and using less than 20 cc of fluid to send, =
maintain, and return the treatment elements. =
The treatment elements 658 are preferably radioactive
sources as described within Canadian Patent File No. 2,222,706,
filed April 4, 1997 which may be referred to for further details.
The treatment elements 658 consist of twelve radioactive
cylinders 660 in series and two marker seeds 659a and 659b, one
at each end of the radioactive train. The marker seeds 659a and
659b are used to properly position the treatment elements 658 at
CA 02577174 2008-08-18
58
the treatment site and are preferably gold or gold plated
since gold is visible under fluoroscopy, which is used to
monitor the radiation delivery. To decrease the source train
delivery time to and retrieval time from the distal end of the
catheter, the ends of the marker seeds 659 may be slotted or
marker seeds can be of gold tubing filled with epoxy. Most
preferably, the distal end of the distal marker seed 659 is
slotted to prevent it from blocking the opening to the
intraluminal connector 646 and the proximal end of the
proximal marker seed 659 is slotted.
In addition to the radiation doses described in the above
referenced Canadian Patent File No. 2,222,706, filed April 4,
1997, a therapeutic radiation dose of 14 Gy at 2 mm in vessels
of approximately 2.7 to approximately 3.2 mm in diameter or
of 18 Gy at 2 mm in vessels of approximately 3.2 to
approximately 4.0 mm in diameter may be administered to the
patient.
At specific times during the radiation therapy procedure,
it may be necessary or desirable to determine the position of
the treating elements 658 and marker seeds 659 with respect to
the quartz sleeve 518 in the transfer device 500. For
example, the user may need to verify that all twelve treating
elements 658 and two marker seeds 659 are present within the
quartz sleeve 518 before delivery of the elements to the
distal end of the catheter 647, and for safety reasons must be
sure that all of the treating elements 658 and marker seeds
659 are within the quartz sleeve 518 prior to closing the gate-
578a and disconnecting the catheter 647 from the transfer
device 500.
To determine whether or not all of the treatment eleraents
658 are within the quartz sleeve 518, an electronic detection
system,. which measures the presence or non-presence of the
distal gold marker seed 659 at a single position within the
quartz lumen 572, is included in the transfer device 500.
This electronic detection system functions similarly to the
previously described detection system to determine and
CA 02577174 2008-08-18
59
indicate whether or not the treatment elements 658 are within
the quartz sleeve 518. However, the means employed by the
electronic detection to achieve the end result is altered
slightly to produce a simpler, more efficient system, and a
more accurate reading of the location of the treatment
elements 658 and marker seeds 659a and 659b.
The system detects a gold marker colorimetrically by
shining light of different wavelengths onto the small area
where the gold marker should reside within the quartz housing
518 and then measuring the reflectivity. Based on the way
reflectivity varies with wavelength, the system determines
whether a gold object (gold marker) or non-gold object
(stainless steel seed, background, or saline filled quartz
lumen) is occupying the area. If a gold marker seed is
detected, it would be reasonable to conclude with a safe
degree of certainty that it is the distal marker seed 659b and
that all of the elements proximal to the distal marker seed
659b are also within the quartz housing. To increase the
degree of certainty that all seeds are within the quartz
housing 518, the electronic sensor can be made to determine
whether both marker seeds 659a and 659b are properly
positioned within the quartz housing 518. However, , this
will require more space within the transfer device housing for
additional electronic and optical components.
In practice, photosensors are not equally sensitive to
blue and red light and the intensity of one or the other must
be adjusted by a fixed compensation factor to achieve the
condition where the photosensor electrical output is the same
for both colors. This technique is well known to those well
versed to opto-electronics, and it will be assumed in the rest
of this description that where it is stated that the red and
blue intensities are equal, it is meant that they are equal as
measured by the output of the photosensor.
In addition to detecting the absence or presence of a
gold marker at a specific position in the quartz sleeve lumen
CA 02577174 2008-08-18
Wo 98/11936 PCT/US97/16856
572, the electronics wait in a low povier state for the power
button 506 to be pressed, then flash two indicator Light-
Emitting Diodes (LEDs) 508a and 508b on and off for about 4.7
seconds after the power button 506 has been pressed to
5 indicate that the LEDs 508a and 508b and batteries 664 are
functional, indicate whether a gold marker is detected by
illuminating one of two indicator LEDs 508a and 508b, and
finally automatically return to the low power state after five
minutes has elapsed to conserve the battery power, or restart
10 the five minute timing period if the button 506 is pressed
again during those five minutes.
The electronic system is powered by a 6v battery pack 664
which contains two 3v lithium cells used in series to
produce +6v. The output is also inverted to produce a -6v
15 supply required by the electronic circuitry. Examples of such
batteries include Sanyo CR-P2, Panasonic CR-P2, and Duracell
DL223A batteries. For safety precautions, a fuse is in series
with the battery. When necessary, the upper shell half 502a
of the transfer device can be removed to replace the battery
20 pack.
The power supply is controlled by a sleep circuit.
Applying power turns the sleep circuit off, which in turn
shuts down the power supply so that it draws only enough power
to keep the system alive. The on-switch 666 is a single pole'
25 double throw (SPDT) push button switch 506. When the switch
666 is closed by momentarily pressing the button 506 from the
exterior of the transfer device 500, the sleep circuit is
awakened and turns on the power supplies 668,670, one
generating +5v and the other generating -5v. The power
30 generated is first applied by starting the countdown of an
internal timer ( a counter driven by 27.3 Hz) 672 set for
five minutes. At the end of five minutes the power supplies
668, 670 are turned off and the sleep circuit becomes inactive
until the next time the switch 666 is closed. If the button
35 506 is pressed during the five minute timing period, the
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WO 98/11936 PCTIUS97/16856
61
timing period is reset allowing the power to stay on longer
than five minutes. The internal timer 672 can be set for one
of several durations in the existing in the existing design.
Each time the five minute timer 672 is started, a 4.7 second
test phase 674 also begins and enables a 3.4 Hz oscillator
676 which is derived from a 3.5 kHz oscillator 690. The 3.4
Hz oscillator 676 and the 4.7 second time 674 are applied to
the indicator LED drivers 677 to flash the two indicator LEDs
508a and 508b (one is green and the other is amber) on and off
simultaneously at 3.4 Hz for 4.7 seconds. This action informs
the user that the batteries"664 and indicator LEDs-508a and
508b are in working order. After the 4.7 second test phase
674, the system goes into its normal detection mode.
The detection mode uses the optical properties of
15, stainless steel (the material encapsulating the radioactive
isotope) and gold (the material or plated material of the
marker seeds) and the resulting different reflectivity's of
red -and blue light on each stainless steel and gold. The
optics of the system include a blue LED 678 employing Gallium
Nitride (GaN), a red LED 680 employing Gallium Phosphide
(GaP), a photosensor 682 including a photo diode and
integrated amplifier, a GRIN (Gradient'Index) lens 684, and a
second photosensor 686, which are all housed within the block
member 564 that houses the quartz 518. In Figure 51C the
first photosensor 682 is perpendicularly oriented with respect
to the quartz sleeve 518 , and the blue and red LEDs 678, 680
are oriented at an angle on either side of the first
photosensor 686. Channels 688 within the body direct light
from the LEDs 678,680 to a targeted location along the quartz
sleeve 518 and also direct the reflected light back to the
first photosensor 682. The GRIN lens 684, positioned between
the quartz sleeve 518 and the first photosensor 682, focuses
on the quartz lumen 572 at the site where the distal gold
marker 659b should reside when all of the treating elements
CA 02577174 2008-08-18
NN'O 98/11936 PCT/L'S97/16856
62
518 are within the quartz sleeve 518. The GRIN lens 684 then
produces an image that becomes roughly focused onto the
surface of the photodiode. The axes of the GRIN lens, the red
and blue LEDs, and the first photosensor must all intersect at
or very near the same point along the axis of the quartz
housing 518 to reliably determine the presence or non-presence
of a gold marker seed.
The blue and red LEDs 678, 680 used in this system supply
blue and red light at peak wavelengths of 450 nanometers (nm)
and 700 nanometers (nm) respectively. At 450 nm stainless
steel has--more than 90% reflectance and gold has about 35%
reflectance; at 700nm both stainless steel and gold have more
than 90% reflectance. This means that stainless steel
reflects blue and red light about equally well and gold
reflects well in the red light but poorly in the blue light
(gold actually absorbs the blue light). Therefore, the
measurement of the blue/red ratio of reflected light can
unambiguously determine whether or not a gold colored object,
in this case a gold marker, is in the photosensor's field of
view.
An analog clock oscillator 690 which oscillates at 3.5kHz
runs through a flip flop 692 where its frequency is divided by
two to create two signals, each having a frequency of 1.75
kHz, to flash the blue and red LEDs 678, 680 in turn (180
degrees out of phase). One of the two signals is applied to
the blue LED driver 694 and the other is applied to the red
LED driver 696 so that each LED 678,680 is driven at
approximately 1.75 kHz. Therefore, the on time and the off
time of the blue and red LEDs 678,680 are equal as they take
turns flashing on and off. The flashes of blue and red light
travel from the LEDs 678, 680, through channels 688 within the
block member 564, and through the quartz 518 to the targeted
location where the distal gold marker should be if all of the
seeds are within the quartz lumen 572. If a stainless steel
CA 02577174 2008-08-18
\N'098/11936 PCT/US97/16856
63
seed or fluid is occupying the targeted location, then both
the red and blue light are reflected equally well
(approximately 96%). If nothing fills the quartz lumen 572 at
the targeted location, then the background, as long as it is
untinted, also reflects both blue and red light similarly to
that of stainless steel. If a gold marker seed is within the
targeted location, then the red light is reflected but much of
the blue light is absorbed. A first photosensor 682,
consisting of a photo diode and an integrated amplifier, is
optically coupled to the targeted location within the quartz
518 by the GRIN lens 684 so that the photosensor 682 can
measure the reflectivity in each the blue and red light. From
the measured reflectivities, the blue/red ratio of reflected
light is used to determine the presence or absence of a gold
marker.
The viewing window 516 along the top 502a of the transfer
device 500 allows ambient light to also be reflected off of
the object within the field of view of the photosensor 682.
The photosensor,682 will detect the ambient light in addition
to the red and blue light. The signal of the ambient light
superimposed on the signal of each the blue and red LEDs 678,
680 may affect the output of the photosensor 682. The
photosensor 682 must be operational with light coming in
through the transparent viewing window 516; therefore, the
signals due to ambient sources must be removed from the
system. This is done by using in series a high-pass filter
698, a buffer 700, a synchronous detector 702 and a low pass
filter 704. The high-pass filter removes all DC (direct
current) light signals (e.g. daylight or flashlight); the
buffer helps the synchronous detector to reduce background
noise by providing a low impedance drive. The synchronous
detector is a circuit which is synchronized with the blue and
red LED pulses. The synchronous detector processes the blue
and red signals using the same 1.75 kHz oscillator used to
drive the blue LED 678 and removes all signals except for
CA 02577174 2008-08-18
WO 98/11936 PCT1US97116856
64
those attributable to the blue and red L=EDs 680 and converts
the resulting AC signal to a DC signal. The amplitude of each
pulse corresponds to how much light is being reflected from
the targeted location and the DC voltage is inversely
proportional to the blue/red ratio of reflected light. In the
case of gold being present at the targeted location, the DC
voltage output is nominally zero. In the case of any other
color present at the targeted location, the output is a non-
null voltage. The last step in filtering out signals from
ambient light is using a low pass filter to remove the ripple
on the DC signal exiting the synchronous detector. -
The system is designed to produce a nominally null
voltage with the detection of gold (and a positive non-zero
voltage with the detection of stainless steel or background)
because a null signal is unaffected by any gains encountered
along the signal path (zero times any magnitude is always
zero) ; thus, the null signal is much less likely to go outside
the tolerance window created around the reference voltage to
be detected (null). Because the null signal is less affected
by variations within the system, such as mechanical tolerances
and temperature changes, it is more reliable than a non-null
voltage. After setting the red LED, the only adjustment
needed for making the output voltage zero when a gold marker
occupies the targeted location is adjusting the intensity with'
which the blue LED 678 illuminates. Two signals of the same
amplitude produce zero volts AC. Conversely, because gold
reflects red and absorbs blue when the blue and red LEDs 678,
680 illuminate with the same intensity, the photosensor 682
sends out signals of different amplitudes (high signal for
blue and low signal for bred) which are converted into a non-
null DC voltage. In order for the presence of gold to produce
a null, gold, not stainless steel, must produce equal amounts
of reflection for both the blue and red light. This is done
by increasing the drive of the blue LED 678 while maintaining
the drive of the red LED 680 constant so that the blue LED 678
CA 02577174 2008-08-18
illuminates with greater intensity than the red LED 680. The
amount by which the drive must be increased is that which
produces equal amplitudes for both red and blue reflected
light. By increasing the intensity of the blue light by a
5 specific percentage, gold now reflects the blue light equally
as well as the red in comparison to absorbing the blue when
the red and blue LEDs 680, 678 have the same drive. Now gold
reflects equal amounts of the blue and red light which
produces no AC signal from the photosensor 682, thus, creating
10 a null. On the other hand, the reflection of stainless steel
is brighter with blue because of the boost given to the blue
LED driver 694; therefore, the blue signal is larger than the
red signal and the resulting square wave produces a non-zero
DC voltage. To make sure the stainless steel treating
15 elements and the background always produce a non-null output
voltage, they should be untinted or tinted blue so as to
reflect blue and absorb red, which is the opposite of what
gold does.
When the DC signal is at nominally zero volts, the system
20 will indicate the detection of gold. In practice, however,
due to certain variations within the system, the DC signal
will rarely read as zero volts. A positive threshold
detector 706 is included in the system to compare the
threshold reference voltage with the filtered and rectified
25 DC signal (a true window detector with both positive and
negative thresholds centered around zero is not necessary
because signals from the stainless steel seeds, saline, and
quartz lumen are found to always be positive). The buffered
+2.5 v reference voltage 708 travels through a potential
30 divider 710, followed by a unity gain buffer 712 to generate
the threshold reference voltage WIN+ 714. The threshold
detector 706 receives the DC signal and determines whether or
not it exceeds the positive threshold(for example, +450
millivolts). If the signal does not exceed the threshold,
35 then the threshold detector 706 decides that the signal is
CA 02577174 2008-08-18
66
consistent with the presence of gold. The threshold can be
changed in order to vary the tolerance of the system to
errors. After the signal goes through the threshold detector
706, the decoded signal enters the two drivers for the
indicator LEDs 508a and 508b. If the decoded signal indicates
that gold is present, then the green LED 508a along the top
502a of the transfer device 500 within the quartz retainer 730
is illuminated, displaying to the user that all of the
treating elements are within the quartz housing 518. If the
decoded signal indicates that gold is not present, then the
amber LED 508b along the top 502a of the transfer device 500
within the quartz retainer 730 is illuminated, displaying to
the user that possibly not all of the treating elements-are
within the quartz housing 518.
Both the blue and red LEDS 678, 680 are temperature
sensitive. The red LED output significantly decreases as the
temperature rises and significantly increases as the
temperature drops. These temperature induced changes in the
red LED output will disturb the blue/red ratio of reflected
light and may hinder, the system's ability to detect the
presence of gold. To stabilize the red LED output, a
brightness control loop is included to regulate the output and
compensate for any temperature effects so as to hold the red
LED output constant. The blue LED 678, however, is
sufficiently temperature stable over the normal operating
temperature range of +10 C to +35 C; therefore, no brightness
control loop is necessary for the blue LED 678. The red LED
brightness control loop incorporates a second photosensor 686.
The second photosensor 686 compensates for the temperature
induced changes in the LED output by "staring" at the tip of
the red LED 680 only and measuring how much light it is
generating. The second photosensor 686 is positioned at a 90
angle with respect to the longitudinal axis of the red LED
680. The red LED output signal is detected in the same way as
CA 02577174 2008-08-18
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the blue/red reflective signal by flowing through a high-pass
filter 716, buffer 718, synchronous detector 720 and a low
pass filter 722. The outcoming DC signal then passes through
the noninverting DC amplifier 724 to set the control loop gain
726. The signal adds either a positive or negative gain to
the reference signal (RED REF) 727 that sets the red LED drive
range . The adjusted signal entering the red LED driver
maintains the red LED output constant even though the actual
amount of light for any given current may vary.
A block diagram of the electronics used to
colorimetrically detect the distal gold marker 659b is shown
is Figure 60. The electronics are built onto two printed
circuit boards, PCB A and PCB B. These printed circuit boards
can be seen in Figures 62A and 62B. For testing procedures
each PCB has a test connector which makes accessible signals
and voltages within the circuit. The PCB's are stored within
a plastic bag for protection against moisture and mounted on
the under side of the chassis within the transfer device. The
schematic diagrams of the electronics on PCB A are shown in
Figures 61A-B and the schematic diagram of the electronics on
PCB B is shown in Figures 61C-1 and C-2. Figure 61 D is a
schematic of the distribution board which is housed on top of
the battery pack 664 and Figure 62C shows the mechanical
outline of the distribution board. The electrical connections
between the different parts of the detection system are shown
in Figure 63A and an equivalent circuit for the circuitry
shown in Fig 63A in addition to showing how the connections
are routed through the distribution printed circuit board and
the micro printed circuit boards which are mounted on the two
photosensors 682 and 686.
As a backup to the electronic source detection system, a
window 516 above the quartz housing 518 allows the user of the
transfer device 500 to visually detect whether or not all of
the treating elements 658 are within the quartz housing 518 by
CA 02577174 2008-08-18
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'0.98/11936 PCT/US97/16856
68
either detecting the presence of each marker seed 659a and
659b on either side of the treating elements or by counting
the number of treating elements 658 and marker seeds 659
within the quartz housing 518. To assist the user with visual
detection, a magnifying lens 728, as shown in Figures 48, 50,
and 51C, is secured to the top portion of the block portion
564 where it is situated directly above the quartz lumen 572.
The magnifying lens 728 is also supported by the quartz
retainer 730; therefore, the indicator LEDs 508a and 508b are
also magnified. The lens used may magnify in one or two
dimensions and may have an order of magnification of 2X or
greater. The lens is a cylindrical glass lens of plano-convex
form. However, other lenses may be used.
Although the above inventions has been described in terms
of certain specific embodiments, it is understood that various
changes and modifications may be made without departing from
these inventions and reference should be made to the appended
claims to determine the proper scope of these inventions.
