Note: Descriptions are shown in the official language in which they were submitted.
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OPTICAL CATHETER AND PULLBACK AND ROTATION SYSTEM AND METHOD
RELATED APPLICATIONS
This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional
Application
No. 60/862,309, filed on October 20, 2006, which is incorporated herein by
reference in its entirety.
BACKGROUND OF THE INVENTION
Catheter-based optical systems are applicable to a number of diagnostic and
therapeutic
medical applications. Optical tomography, usually optical coherence tomography
(OCT), is used to
provide spatial resolution, enabling the imaging of internal structures.
Spectroscopy is used to
characterize the composition of structures, enabling the diagnosis of medical
conditions by
differentiating between cancerous, dysplastic, and normal tissue structures,
for example.
Reflectance analysis is a simplified form of spectroscopy that analyzes
optical properties of
structures, typically in specified wavelength bands. Fluorescence and Raman
spectral analysis
involve exciting the tissue at one wavelength and then analyzing light at
fluorescence wavelengths
or Raman shifted wavelengths due to a process of inelastic photon scattering.
They all share certain
catheter requirements including the need to transmit an optical signal to the
internal structures of
interest and then detect returning light, often transmitting that returning
light back along the length
of the catheter.
For example, in one specific spectroscopic application, an optical source,
such as a tunable
laser, is used to access or scan a spectral band of interest, such as a scan
band in the near infrared
wavelengths or 750 nanometers (nm) to 2.5 micrometers ( m) or one or more
subbands. The
generated light is used to illuminate tissue in a target area in vivo using
the catheter. Diffusely
reflected light resulting from the illumination is then collected and
transmitted to a detector system,
where a spectral response is resolved. The response is used to assess the
composition and
consequently the state of the tissue.
This system can be used to diagnose atherosclerosis, and specifically to
identify
atherosclerotic lesions or plaques. This is an arterial disorder involving the
intimae of medium- or
large-sized arteries, often including the aortic, carotid, coronary, and
cerebral arteries.
Diagnostic systems including Raman and fluorescence-based schemes have also
been
proposed. Other wavelengths, such as visible or the ultraviolet, can also be
used.
In OCT applications, a coherent optical source is used to illuminate tissue in
a target area.
By analysis of the interference between light returning from the target area
and light returning from
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a reference arm, depth information is generated providing information of both
the surface topology
and subsurface structures.
Other, non-optical, technologies also exist. For example, intravascular
ultrasound (IVUS)
uses a combination of a heart ultrasound (echocardiogram) and cardiac
catheterization. In this
application, an ultrasound catheter is inserted into an artery and moved to a
target area. It then both
generates and receives ultrasound waves that can then be constructed into an
image showing the
surface topology and internal structures at the target area.
The probes or catheters for these applications typically have small lateral
dimensions. This
characteristic allows them to be inserted into incisions or lumen, such as
blood vessels, with lower
impact or trauma to the patient. The probe's primary function is to convey
light to and/or receive
light from a target area or area of interest in the patient for the optical-
based technologies. In the
context of the diagnosis of atherosclerosis, for example, the target areas are
regions of the patient's
arteries that may exhibit or are at risk for developing atherosclerotic
lesions.
In each of these applications, the target areas or areas of interest are
typically located lateral
to the catheter head. That is, in the example of lumens, the probe is advanced
through the lumen
until it reaches the areas of interest, which are typically the lumen walls
that are adjacent to the
probe, i.e., extending parallel to the direction of advance of the probe. A
"side-firing" catheter head
emits and/or receives light or ultrasound signals from along the probe's
lateral sides. In the
example of catheters for optical-based applications, the light propagates
through the probe, until it
reaches the probe or catheter head. The light is then redirected to be emitted
radially or in a
direction that is orthogonal to the direction of advancement or longitudinal
axis of the probe. In the
case of light collection, light from along the probe's lateral sides is
collected and then transmitted
through the probe to an analyzer where, in the example of spectroscopic
analysis in the diagnosis of
atherosclerosis, the spectrum of the returning light is resolved in order to
determine the composition
of the vessel or lumen walls.
In order to fully characterize target areas, relatively long regions of
tissue, such as blood
vessels, must be scanned and in the case of blood vessels an entire 360 degree
circumference of
vessels must be captured. To perform this combination of longitudinal and
rotational movement,
the catheters are typically driven by a device called a pullback and rotation
(PBR) system.
Pullback and rotation systems connect to the proximal end of the catheter.
They typically
hold an outer sheath or jacket stationary while an inner catheter scanning
body, including the
catheter head are rotated and withdrawn through a segment of the blood vessel.
This scanning
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combined with driving the catheter head produce a helical scan that is used to
create a raster-
scanned image of the inner walls of the blood vessel.
SUMMARY OF THE INVENTION
In general, according to one aspect, the invention features a catheter system,
comprising an
intraluminal catheter for insertion into a patient and a handle portion. The
intraluminal catheter
includes an outer jacket and an inner scanning body that rotates and moves
longitudinally within
the outer j acket. The handle portion includes an outer housing mechanically
coupled to the outer
jacket and an inner carriage mechanically coupled to the inner scanning body.
This combination provides pullback and rotation scanning when the inner
carriage is
extracted and driven by a pullback and rotation system but ensures that the
system is robust during
transportation or when otherwise not being used.
This basic configuration can be used for optical catheters or catheters using
other analysis
modalities, such as IVUS. In the example of optical catheters, systems using
spectroscopic, optical
tomography, Raman, and fluorescence analysis modalities, for example, are
compatible with this
basic design.
In a preferred embodiment, the inner scanning body comprises an optical fiber
bundle,
including at least one optical fiber, for transmitting optical signals between
a head of the
intraluminal catheter and the inner carriage. In this case, the inner carriage
preferably comprises
one or more optical connectors for providing optical connection to the optical
fiber bundle.
A torque cable is preferably provided for transferring rotation from the inner
carriage
through the inner scanning body to a head of the intraluminal catheter.
Typically, the outer housing functions as a handle for attachment of the
catheter system to
the pullback and rotation system. To facilitate alignment, the inner carriage
is provided with a
bayonet member projecting axially from a proximal side of the inner carriage
for rotationally
aligning the inner carriage during attachment to a pullback and rotation
system.
A catheter carriage interlock system is preferably used to secure the inner
carriage within
the outer housing at least during transportation or when otherwise not in use.
This catheter carriage
interlock system prevents rotation of the inner carriage within the outer
housing and extraction of
the inner carriage from the outer housing.
In the preferred embodiment, a release member on a pullback and rotation
system
disengages the catheter carriage interlock system so that the inner carriage
is able to rotate and
move relative to the outer housing.
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In general, according to another aspect, the invention features a catheter
carriage interlock
system for an optical catheter system comprising an intraluminal catheter that
provides optical
signals to a patient and carries optical signals from the patient, an outer
housing, and an inner
carriage that moves longitudinally relative to the outer housing and rotates
relative to the outer
housing during operation when the catheter system is driven by a pullback and
rotation system.
The interlock system comprises a carriage locking system that prevents
rotation and longitudinal
movement of the inner carriage in the outer housing. An unlocking system on
the pullback and
rotation system unlocks the carriage locking system to free the inner carriage
to rotate and move
longitudinally in the outer housing when the catheter system is connected to
the pullback and
rotation system.
In general, according to still another aspect, the invention features a
carriage interlock
method, comprising preventing rotation and longitudinal movement of the inner
carriage in the
outer housing at least during transportation of the optical catheter system
and unlocking the inner
carriage to free the inner carriage to rotate and move longitudinally in the
outer housing when the
optical catheter system is connected to a pullback and rotation system.
In general, according to one aspect, the invention features a pullback and
rotation system.
This system comprises a frame and a catheter system interface, attached to the
frame, to which a
catheter system, comprising an intraluminal catheter, is coupled. A carriage
drive system is further
provided that moves longitudinally and rotates relative to the frame to
provide rotation and
longitudinal drive to the catheter system. A longitudinal drive system has a
drive motor for
advancing and/or withdrawing the carriage drive system and a manual drive
input enabling a user to
manually advance or withdrawal the carriage drive system.
In the preferred embodiment, a clutch is used for selectively engaging the
drive motor of the
longitudinal drive system. An encoder is also desirable for tracking the
advance and withdrawal of
the carriage drive system both when the carriage drive system is being driven
by the drive motor
and when the drive carriage system is being driven by the manual drive input.
Ideally, the manual
drive input is mechanically coupled to encoder and the clutch selectively
couples the drive motor to
the encoder.
In one implementation, a timing belt system is used to couple the drive motor
and the
manual drive input to the carriage drive system.
In the preferred embodiment, the carriage drive system further comprises a
drive frame and
a drum that rotates on the frame. The drum carries an optical connector for
providing an optical
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connection to the catheter system. A rotation motor encoder is used to rotate
the drum on the drive
frame and monitor the rotation of the drum.
The provision of an optical rotary coupler enables transmission of optical
signals between
the rotating drum and the frame. A detector on the drum is used for detecting
optical signals
returning from the catheter system.
In general according to another aspect, the invention features a method for
pullback and
rotation drive of a catheter system. The method comprises coupling the
catheter system to an
interface, driving the catheter system longitudinally and rotationally, and
enabling a manual control
by a user to longitudinally advance or withdrawal the catheter system.
In general, according to still another aspect, the invention features a
pullback and rotation
system for an optical catheter system. This system comprises a frame and a
catheter system
interface, attached to the frame, to which a catheter system, comprising an
intraluminal optical
catheter, is coupled. A carriage drive system is further provided, which moves
longitudinally and
rotates relative to the frame to provide rotation and longitudinal drive to
the catheter system. A
longitudinal drive system, comprising a drive motor, advances and/or withdraws
the carriage drive
system.
In general, according to one aspect, the invention features a pullback
carriage interlock
system for a catheter pullback system. The pullback system comprises a frame,
a catheter system
interface, attached to the frame, to which a catheter system, comprising an
intraluminal catheter, is
coupled, a pullback carriage drive system that moves longitudinally relative
to the frame to provide
longitudinal drive to the catheter system. The pullback carriage interlock
system comprises a
latching system for holding the pullback carriage drive system when the
catheter system is being
attached to the pullback system.
In the preferred embodiment, a release system is used for unlocking the
latching system to
enable longitudinal movement of the pullback carriage drive system relative to
the frame upon
connection of the catheter system to the pullback system. This latching system
comprises at least
one latch arm that engages a carriage drive frame of the pullback carriage
drive system when fully
advanced toward the catheter system interface.
Further, the release system preferably unlocks the latching system upon
connection of the
catheter system to the pullback system, the release system being engaged by
the coupling of the
catheter system to the catheter system interface.
In general, according to another aspect, the invention features an interlock
method for a
catheter pullback system. The method comprises preventing longitudinal
movement of the
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pullback carriage drive system, coupling the catheter system to the catheter
system interface while
preventing the longitudinal movement, and releasing the pullback carriage
drive system after
coupling of the catheter system.
In general, according to one aspect, the invention features an intraluminal
optical analysis
system comprising an intraluminal optical catheter that provides optical
signals to a patient and
carries optical signals from the patient to enable optical analysis of tissue
within the patient. It
further has a rotation system including a frame and a carriage drive system
that rotates relative to
the frame to provide rotational drive to the optical catheter.
The intraluminal spectroscopic analysis system comprises an optical source,
tunable laser
for example, for generating the optical signals and a delivery channel for
transmitting the optical
signals to the intraluminal optical catheter via the carriage drive system
through a rotary optical
joint. A delivery channel detector on or off the carriage drive system
monitors the optical signals
being transmitted on the delivery channel and a collection channel detector on
the carriage drive
system detects optical signals from the patient.
In the preferred embodiment, the system has a rotary joint and/or laser noise
suppression
system that uses common mode rejection to reduce noise from the optical
signals from the patient
introduced by the rotary optical joint and/or laser by reference to the
delivery channel detector and
the collection channel detector. In the current implementation, a tap is used
to divert a portion of
the optical signals to the delivery channel detector.
An electrical slip ring assembly is preferably used for transmitting
electrical signals from
the delivery channel detector from the rotating carriage drive system after
noise suppression in
response to the delivery channel detector.
In general, according to another aspect, the invention features a method for
an intraluminal
spectroscopic analysis system. This system comprises an intraluminal optical
catheter that provides
optical signals to a patient and carries optical signals from the patient to
enable spectroscopic
analysis of tissue within the patient. A rotation system, including a frame
and a carriage drive
system that rotates relative to the frame, provides rotational drive to the
optical catheter. The
method comprises generating the optical signals and transmitting the optical
signals to the
intraluminal optical catheter via the carriage drive system through a rotary
optical joint. The
optical signals being transmitted on the delivery channel are monitored on or
off the carriage drive
system. Also, optical signals from the patient are detected on the carriage
drive system.
The above and other features of the invention including various novel details
of construction
and combinations of parts, and other advantages, will now be more particularly
described with
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reference to the accompanying drawings and pointed out in the claims. It will
be understood that
the particular method and device embodying the invention are shown by way of
illustration and not
as a limitation of the invention. The principles and features of this
invention may be employed in
various and numerous embodiments without departing from the scope of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, reference characters refer to the same parts
throughout the
different views. The drawings are not necessarily to scale; emphasis has
instead been placed upon
illustrating the principles of the invention. Of the drawings:
Fig. 1 is a side-plan view showing a catheter system according to the present
invention;
Fig. 2 is a side cross-sectional view of the catheter system;
Fig. 3 is a side cross-sectional view of the catheter system showing the
carriage interlock
system shown in an open condition;
Fig. 4 is a perspective side view of a pullback and rotation system according
to the present
invention;
Fig. 5 is a partial side perspective view showing the axial drive system for
the pullback and
rotation system;
Fig. 5A is a schematic view showing the axial drive system for the carriage
drive system;
Fig. 6 is a partial front perspective view of the carriage drive system of the
pullback and
rotation system;
Fig. 7 is a partial reverse angle perspective view of the carriage drive
system for the
pullback and rotation system;
Fig. 7A is a block schematic plan showing the optical path for the catheter
and pullback and
rotation system of the present invention;
Fig. 8 is a partial side perspective view of the pullback and rotation system
showing the
carriage drive locking system;
Fig. 9 is a partial side perspective view of the carriage drive locking system
of the present
invention;
Fig. 10 is a front plan view showing the catheter locking system; and
Fig. 11 is a front perspective view of the catheter locking system according
to the present
invention.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 1 shows a catheter system 100 connected to a pullback and rotation system
200, which
have been constructed according to the principles of the present invention.
Generally, the catheter system 100 comprises an intraluminal catheter 110.
This is typically
inserted into a lumen within a patient, such as a blood vessel, particularly
an artery. It is moved
through the arterial network of the patient until a catheter head 130 is
proximal or adjacent to a
region of interest, such as potential site of a lesion within the coronary or
carotid artery, for
example.
Fig. lA shows the intraluminal catheter 110 comprising an outer jacket 82 and
an inner
catheter scanning body sb including the catheter head 130. In operation,
optical signals, such as a
tunable signal that is spectrally scanned or tuned over a spectral scan band
or a broadband optical
signal, are transmitted to the head on a delivery fiber 74 of an optical fiber
bundle ofb of inner
catheter scanning body sb. The optical signal of the delivery fiber is
directed to exit from the side
of the head 130 by an angle reflector 78 through a window 76. Returning light,
such as scattered
and diffusely reflected light from the region of interest of the inner luminal
walls 2 is captured by
collection reflector 80 to be transmitted in a collection fiber 72.
In other examples, the delivery fiber transmits an excitation optical signal
for Raman or
fluorescence analysis. A narrowband optical signal is often used in
reflectance analysis systems.
In order to enable scanning of the inner luminal walls 2, inner catheter
scanning body sb
including the head 130 is rotated within a protective jacket or sheath 82, see
arrow 84, while
typically being simultaneously translated longitudinally within the jacket 82,
see arrow 86. The
scanning body typically comprises an outer torque cable 85 for transferring
rotation to the head
130. In the current embodiment, the torque cable 85 comprises contrahelically
wound wire layers
to enable low backlash torque transfer along the length of the intraluminal
catheter 110. The jacket
82 ensures that the lumen is not damaged by the rotation 84 and longitudinal
movement 86 of the
inner catheter scanning body sb.
Returning to Fig. 1, the proximal end of the catheter system 100 has a
catheter handle
housing 112. This housing 112 is typically the portion of the catheter system
100 that is held by the
medical personnel during some operations such as when attaching the catheter
system 100 to a
pullback and rotation system 200.
The pullback and rotation system 200 controls the movement of the inner
catheter scanning
body sb and catheter head 130 both in terms of rotation 84 and longitudinal
movement 86 to
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typically helically raster scan the internal walls 2 of the coronary artery,
for example, to assess and
characterize any tissue, lesions, or other problems in and on those internal
walls 2.
In other examples, the catheter and head are configured for OCT analysis. In
still other
examples, the catheter and head are used for IVUS applications. As such, the
optical components
are replaced or augmented by ultrasonic transducers in the head 130, for
example.
Fig. 2 shows the proximal end of the catheter system 100. It comprises the
handle housing
112, providing a sterile field surrounding the internal components of the
catheter system 100. The
handle housing 112 further comprises a housing apron 112a that flares moving
proximally in order
to protect the coupling components housed within the housing 112. In contrast,
moving distally,
the housing further comprises a j acket fixing block 112b. The catheter j
acket 82 is rigidly bonded
to the jacket fixing block 112b such that the jacket 82 is stationary with
respect to the housing 112,
ensuring that the inner catheter scanning body sb moves with respect to the
jacket 82. Finally, the
distal end of the housing comprises a flexible nose portion 112c to prevent
crimping of the catheter.
Within the housing 112 is a catheter carriage 118. The optical fiber bundle
ofb is secured to
the carriage 118 so that rotation 52 of the carriage or longitudinal movement
50 is transferred to the
catheter head 130. The optical fiber bundle ofb in one embodiment, comprises
the delivery fiber
74, which in one example is single spatial mode fiber that transmits an
optical spectroscopy signal,
such as a tunable signal generated by a tunable laser, to the catheter head
130, and the collection
fiber 72, which is often multimode fiber, that transmits any collected light
by the catheter head 130
through the length of the catheter system 100.
The catheter system 100 has a series of components that form a catheter
carriage interlock
system 180, which prevents the carriage 118 from moving within the housing
body 112 both
rotationally and longitudinally 50 when the catheter system 100 is not
mechanically connected to
the pullback and rotation system 200. However, an unlocking or key system on
the pullback and
rotation system 200 unlocks the carriage interlock system 180 to free the
inner carriage 118 to
rotate and move longitudinally in the housing 112 when the catheter system 100
is connected to the
pullback and rotation system 200.
The interlock system 180 comprises a series of catheter locking levers 116,
that prevent the
carriage 118 from rotating 52 and being extracted from the housing 112 when
the catheter system
100 is not connected to the pullback and rotation system 200 yet allow the
carriage 118 to rotate
within the housing body 112 and to move axially out of the body 112 when the
catheter system 100
is connected to the pullback and rotation system 200. Specifically, in one
example, more than two
locking levers are used, such as four in one implementation.
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Each catheter locking lever comprises a lever pivot 116p, a ring engagement
nose 116n, and
a lever arm 116a. When the catheter system 100 is not connected to the
pullback and rotation
system 200, the lever arms 116a of the catheter locking levers 116 are in
engagement with an outer
periphery 118p of the carriage 118. This prevents the rotation of the carriage
118 within the
housing body because of the interference between the lever arm 116a and
carriage rotation
shoulders 118 of the carriage 118. Specifically, when the carriage 118 is
fully inserted into the
body, the lever arms 116a are resiliently biased against the catheter carriage
118 at region 118p and
fall between adjacent, axially-extending carriage rotation shoulders 118s and
thereby prevent the
catheter carriage 118 from rotating within the housing body 112.
The resilient biasing of the lever arms 116 is provided by a flexible circular
band 116b that
extends around the outer periphery of the array of lever arms 116. In a
current embodiment, the
band 116b is fabricated from a synthetic rubber material such as EPDM
(ethylene propylene diene
monomer) rubber. This is a low creep, sterilization resistant material. In
other implementations,
the resilient biasing is performed by spring elements, such as leaf springs,
that are integrally formed
with the lever arms 116.
The engagement of the lever arms 116a against region 118p of the catheter
carriage 118 also
prevents the catheter carriage 118 from being extracted from the housing body
112. Specifically, if
an extraction force is applied to the catheter carriage 118 relative to the
housing body 112, the lever
arms 116a slide along portion 118p of the catheter carriage 118 to engage with
the extraction
shoulder 118e. This mechanical interference thus prevents the catheter
carriage 118 from being
extracted from the housing body 112 or falling out when the catheter system
100 is not coupled to
the pullback and rotation system 200.
Fig. 3 shows the catheter system 100 coupled to the pullback and rotation
system 200 and
specifically its interaction with the interface release ring 210. The ring
shoulders 210s engage with
the ring engagement noses 116n of the catheter locking levers 116. This causes
the locking levers
116 to pivot on the respective lever pivot 116p against the axially inward
directed bias force of the
band 116b with the lever arm portions 116a of the locking levers 116 rotating
outward thereby
bringing the lever arms 116a out of engagement with region 118p of the
catheter carriage 118. This
allows the catheter carriage 118 to now rotate within the housing 112 because
the lever arms 116a
are no longer interfering with the carriage rotation shoulders 118s. Further,
the lever arms 116a are
now pulled away from the carriage extraction shoulders 118e to thereby allow
the carriage to move
in the direction of arrow 10 and rotate in the direction of arrow 50' relative
to the housing body 112.
Fig. 4 shows the pullback and rotation system 200. It generally comprises a
pullback and
rotation frame 212. A front member 212f of the frame 212 holds the interface
release ring 210 that
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forms part of the catheter interface 205 to which the catheter system 100
connects. A center
member 212b runs laterally from the front member 212f to a rear member 212c.
The pullback and rotation system 200 also comprises a carriage drive system
300 that
couples to the catheter carriage 118. This carriage drive system 300 generally
drives the rotation of
the inner catheter scanning body sb and the catheter head 130 of the catheter
system 100 via the
catheter carriage 118 and also drives the movement of the inner catheter
scanning body sb and the
catheter head 1301ongitudinally in the catheter system 100. The longitudinal
movement is
provided by the movement of the carriage drive system 300 back and forth in
the direction of arrow
50 and the rotation is accomplished by the rotation of a drum system 325 of
the carriage drive
system 300 in the direction of arrow 52.
In more detail, the carriage drive system 300 travels longitudinally on the
pullback and
rotation frame 212 on frame rails 212r formed on either side of the center
member 212b.
Specifically, carriage rollers 330 roll on the rails 212r thereby allowing the
carriage drive system
300 to move laterally on the frame 212. The carriage rollers 30 are joumaled
to roller plates 331
which are attached to a front carriage frame plate 333f and a back carriage
frame plate 333b,
respectively.
The carriage drum system 325 is mounted to rotate on the front carriage frame
plate 333f
and the back carriage frame plate 333b. Specifically, the carriage drum system
325 comprises a
front carriage drum roller 314 and a rear carriage drum base 330.
Optical/electronic boards 335
extend between the drum base 330 and drum roller 314 and contain the
electronic, optical, and
opto-electronic components of the rotating drum system 325. The front carriage
drum roller 314
supports a carriage coupler mount 310. The carriage coupler mount 310 holds a
male optical
duplex coupler 312 that connects to the female duplex optical coupler 120 of
the catheter system
100. Specifically, this provides the optical connection between a delivery
channel provided by
delivery fiber 74 and collection channel provided by the collection fiber 72
of the optical fiber
bundle ofb. A catheter alignment bayonet 114 projects proximally from the
female duplex optical
coupler 120.
The carriage coupler mount 310 also has a bayonet scabbard 310s that is a port
for receiving
the catheter alignment bayonet 114. Thus, upon insertion of the catheter
system 100 into the
pullback and rotation system 200, the catheter alignment bayonet 114 extends
into the bayonet
scabbard 310s to insure that the catheter system 100 and specifically the
catheter carriage 118 is
rotationally aligned to the drum system 325 of the carriage system 300 thus
ensuring alignment
between the female duplex optical coupler 120 and the male optical duplex
coupler 312.
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Further, the carriage coupler mount 310 further comprises a bayonet presence
detector 310d
that senses the presence of the catheter alignment bayonet 114 to thereby
signal to the PBR system
200 when the catheter system 100 is properly connected to the PBR system.
The drum system 325 rotates relative to the carriage frame plates 333f, 333b
under power of
a carriage motor encoder 320. Specifically, the carriage motor encoder 320
drives a roller 323 that
engages teeth on the outer periphery of the front drum 314. Thus, the motor
encoder 320 drives the
drum system 323 to rotate 52 under angular control of its encoder. Three
carriage rollers 327, each
having a female V-shape profile, provide support to the drum 325 by engaging a
V-shaped outer
periphery 314p of the front drum 314 at three distributed points of contact
allowing its rotation.
The carriage drive system 200 also comprises a drum angular position detection
system.
Specifically, an angular position detector 324 is attached to the back
carriage frame 333b of the
carriage frame. The drum base 330 further comprises a flag 322 that passes in
proximity to the
angular position detector 324 and in this way the angular position of the drum
system 325 in the
carriage drive system 300 is detected and specifically its proper orientation
to receive the catheter
system 100 and in the alternative used to calibrate the encoder of the motor
encoder 320 to a known
reference.
Fig. 5 shows the longitudinal drive system for the carriage drive system 300.
The
longitudinal drive system provides for movement both under direct operator
control and under
motor control. The manual operation, i.e., longitudinal movement, arrow 50, of
the carriage drive
system 300 is accomplished by user rotation of the manual pulley 214. This
drives the manual
drive belt 216 that turns the manual belt pulley 218. This movement causes the
carriage drive
system 300 to move back and forth in the direction of arrow 50 depending on
the direction that the
manual pulley 214 is rotated by the operator. In more detail, a timing belt
drive belt 246 stretches
between a pulley below the manual belt pulley 218 to a second timing belt
pulley (see 219 in Fig.
4). The timing belt 246 is further attached to the carriage drive system 300.
A longitudinal drive or
timing belt drive motor 240, hung on the rear member 212c, is also
alternatively used to drive the
carriage drive system 300 back and forth in the direction of arrow 50.
Specifically, the longitudinal
drive motor 240 engages the timing belt 246 via a clutch 242. Thus, when the
clutch 242 is
engaged, the drive motor 240 connects to drive the carriage drive system
3001ongitudinally. An
encoder 244, attached to the rear member 212c, is also provided on the drive
path, specifically the
encoder 244 engages the timing belt 246 via an encoder pulley 247,
specifically engaging the outer
periphery of the timing belt 246 to monitor the axial position of the carriage
system 300 on the rails
212r.
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Fig. 5A schematically shows the mechanical system for driving the carriage
drive system
300. Specifically, it allows for the encoder 244 to monitor the axial position
of the carriage system
300 via the timing belt 246 regardless of whether the linear drive for the
carriage drive system 300
is being provided manually, by the operator using manual pulley 214, or under
control of the
longitudinal drive motor 240. Specifically, the manual pulley 214 and
potentially the drive motor
240 both drive the timing belt 246 that goes to the encoder 244. Thus,
independent of the status of
the clutch 242, being open or closed, the encoder 244 continues to monitor the
position of the
carriage drive system 300.
Fig. 6 is a close-up view showing the male duplex optical couplers 312.
Specifically, the
couplers are housed within the carriage coupler mount 310. Two optical male
adapters, one for the
multimode collection fiber (312c) and one for the single mode delivery fiber
(312d) are provided.
Each adapter has a front dust cover 312d that is closed when the connectors
are not engaged to
thereby protect the sensitive optical fiber end facets within the couplers.
Presently, the Diamond-
brand F-3000 Backplane adapters are used, which provide active push pull
retention.
Fig. 7 is a more detailed partial view in a reverse angle better showing the
optical and
electrical connections for the carriage drive system 300. Specifically, the
input optical fiber 361 of
the delivery channel connects to the rotating carriage drum 325 via an input
optical fiber rotary
coupling 360. This allows the input optical fiber 361 to remain stationary,
i.e., not rotate. In the
current implementation, a tunable laser provides the tunable optical signal on
the input optical fiber
361. In other applications, a narrowband optical source is used for
reflectivity analysis. In other
systems, a broad band source is used.
An electrical slip ring system 363 transmits electrical power and signals to
and from the
rotating drum. Specifically, a spectral analysis system 22 is provided, in one
embodiment, to
receive spectral data from the slip ring system 363 to enable analysis of the
target tissue. A
stabilizing bracket 365 prevents the nominally stationary side of the rotary
coupling from rotating
due to torque transfer through the coupling from the rotating drum 325.
Fig. 7A shows the optical and electrical systems illustrating their
relationship to the rotating
drum 325.
The delivery tunable optical signal, such as generated by a tunable laser 20,
is transmitted
on fiber 361, through the input optical fiber rotary coupling 360, to the
rotating drum 325. The
input optical fiber 361d in the drum 325 connects to a tap 368. This tap 368
directs a portion of the
optical signal transmitted by the input optical fiber 361d, the delivery
channel, to a delivery signal
detector 364 on the drum 325. The remaining signal is transmitted on fiber 361
e of the delivery
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optical fiber 74 of the catheter system 100 via the duplex couplers 312/120.
Any collected optical
signal collected from the catheter head 110 is transmitted through the
collection fiber 72 of the
catheter system 100 and received on the collection optical fiber 370 of the
collection channel. This
optical fiber terminates on a collection optical detector 366.
In general, a delivery channel transmits the optical signals to the
intraluminal catheter 100
via the rotating drum 325 through rotary joint 360 and the delivery channel
detector 364 on the
rotation carriage monitors the optical signals being transmitted on the
delivery channel. The
collection channel detector 366 detects optical signals from the patient. A
noise suppression system
uses the delivery channel detector 364 to reduce noise in the optical signals
from the patient
introduced by the rotary joint 360 and/or laser noise.
Typically, the optical rotary coupler 360 will inject noise. Another source of
noise is the
laser itself due to temporal fluctuations in optical power output. The tap 368
provides a portion of
this delivery optical signal, including any noise to the delivery optical
signal detector 364. Then,
when the returning optical signal from the catheter head 100 is received and
detected by the
collection detector 366, the noise added by the rotary coupling 360 and any
laser noise is removed
by the processing performed by the divider 368. Specifically, the system
provides for common
mode rejection which will remove noise introduced by the rotary joint 360 and
laser noise. Thus,
the output optical signal without the noise is then further provided to the
spectral analysis engine 22
that resolves the spectral response of the patient tissue that allows for its
analysis, for example,
determining the state of the tissue. In other examples, OCT analysis is
performed to determine the
topology of the tissue.
In other embodiments, the delivery optical signal detector is located not on
the rotating
drum 325 but is between the drum 325 and the laser 20. This is used in
situations in which any
noise from the rotary coupler 360 is minimal or outside the signal band.
The incorporation of the optical detectors 364, 366 on the rotating drum 325
provides a
number of advantages. First, since the collection optical detector 366 is on
the drum 325, a second
optical rotating coupler is not required. The information in the optical
signals is transmitted
electrically from the rotating drum 325 via electrical slip ring system 363.
One problem that arises
when using optical rotating rotary coupling is the potential for the creation
of optical noise due to
the rotating movement of the coupler 360. This is addressed in the present
system by the
incorporation of the delivery detector 364 on the rotating drum 325.
Figs. 8 and 9 illustrate the carriage drive interlock system. This interlock
system ensures
that the carriage drive system 300 is and is held at or near the proximal end
of the pullback and
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rotation frame, near the front member 212f especially during the attachment of
the catheter system
100 to the pullback and rotation system 200.
In general, the carriage drive interlock is a latching system 252 for holding
the carriage
drive system 300 of the pullback and rotation system 200 from moving when the
catheter system
100 is being attached to the pullback and rotation system 200. It further has
a release system for
unlocking the latching system 252 to enable longitudinal movement of the
carriage drive system
300 relative to the frame 212 upon connection of the catheter system 100 to
the pullback and
rotation system 200. The interlock latching system 252 ensures that the
carriage drive system 300
does not move freely, specifically in response to any attachment force
supplied by the operator in
order to attach the catheter system 100 to the interface 205 on the pullback
and rotation system 200.
Specifically, two carriage latches 2501ock and engage with two opposed
carriage latch
plates 370 that extend from the front face of the front carriage frame piece
333f. Specifically, each
carriage latch 250 engages with a corresponding carriage latch plate 371 (see
fig. 8, for example) to
lock the carriage drive system 300 in its forward position. A forward position
sensor 290 on the
frame 212 detects the presence of flag arm 390 to confirm that the carriage
drive system 300 is in
its forward most position. In this position, the carriage coupler mount 310
projects thought port
212p in the front member 212f of the frame 212 enabling the carriage 118 of
the catheter system
100 to mechanically and optically mate with the carriage drive system 300.
Each of the carriage
latches 250 is biased into engagement with the plates 371 by a bias spring.
The carriage drive system 300 becomes unlatched only upon full insertion of
the catheter
system 100 onto the pullback and rotation system 200 through the action of the
release system.
Specifically, the full insertion and attachment of the carriage system 100
causes the catheter sensing
pin 256 to move in the direction of arrow 25. This movement pivots the
carriage latches 250 in the
direction of arrow 26 to disengage from the carriage latch plates 371, thereby
freeing the carriage
drive system 300 to move longitudinally on the frame rails 212r.
Fig. 10 illustrates a catheter housing interlock system 270 that ensures that
the catheter
system 100, and specifically the catheter housing 112, is not accidentally
disconnected from the
pullback and rotation system 200. The catheter housing interlock system 270
includes four catheter
housing locking mechanisms 272 for securing the catheter housing 112 to the
front frame member
212f of the pullback and rotation system 200.
Specifically, the catheter housing interlock system 270 comprises a catheter
locking rack
frame 158. When this catheter locking rack frame 158 is depressed by the
operator in the direction
of arrow 32, by applying a downward force on tab 266, it causes the locking
cam gear 260 to rotate
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in the direction of arrow 34. In more detail, guide pin bolts 410 attached to
the front member 212f
guide the rack frame to slide vertically against the force of bias rack
springs 159. A rack gear 158r
(see Fig. 11) of the rack frame 158 engages teeth on the outer periphery of
the locking cam gear
260. The rotation of the cam gear causes the camming surface 260c on the inner
face of the
catheter cam gear 260 to engage and push in a radial inward direction the four
locking rollers 262
as region 260c1 moves away from roller 262 and region 260c2 comes into contact
with rollers 262.
This moves the locking rollers 262 and the latches 264 against the spring
elements 267.
Fig. 11 shows the front side of the catheter interlock system 270. The
interface ring 110 is
removed to expose the latches 264 that would normally extend through the ports
210p of the
interface ring 210, see Fig. 4. The rotation of the cam gear 260 causes the
latches 264 to pivot
radially outward with respect to the central port 212p. Please refer to Fig.
11. The pivoting of the
latches 264 outward causes the latch shoulders 265 to pull away from the
housing locking shoulders
112s of the catheter system 100. Refer to Fig. 3. Thus, only when the operator
applies a downward
force on tab 266, moving the rack 158 against bias spring 159, will the
catheter system 100 become
free from the pullback and rotation system 200. This ensures that the catheter
housing 112 does not
become disconnected from the pullback and rotation system 200 in an
uncontrolled fashion against
the intent of the operator.
While this invention has been particularly shown and described with references
to preferred
embodiments thereof, it will be understood by those skilled in the art that
various changes in form
and details may be made therein without departing from the scope of the
invention encompassed by
the appended claims.
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