Note: Descriptions are shown in the official language in which they were submitted.
5~i8~
-1- 60~12-159
FIBER-OPTIC IMAGE-CARRYING DEVICE
This lnven~ion relates to Eiber~optic image-carrying
devices for examining regions that are remote or diE-ficult of
access.
Such devices are used in medicine ~or examining oryans,
veins and arteries, and other parts of the human body. Similar
devices are used in industry, for internal inspection of engines,
nuclear reactor tubes and other critical areas.
It is desirable to achieve an image-carrying unit that
is very small (e.g., with outside diameter less than 1 mm and
preferably about 0.5 mm or less), which is practical to make and
which has useful image size, field of view and degree o~ contrast.
It is also desirable to achieve a catheter which combines a
flexible image-carrying unit, a means or delivering illumination
to the viewing area and a working channel, in an overall assembly
that likewise is very small, e.g., less than 3 mm overall
diameter.
Summary of the Invention
According to the invention, there is provided a remote
vision micro-optical device in which a lens system of a diameter
.~ ~
r
, ' , ''' ' ', ', ',' ',, ' ~- ~ ,,
~ ' I ~ ' ' ' ~ '' '
:'' ' - ' : ~ ,
. .
~.2'~558~
-2- 60412-159
of about 0.020 inch and comprising at least two substantially
spherical lens surfaces is adapted to deliver an image lnto an
elongated image-carrying member of generally eorresponding
diameter, the image-carrying member comprised oE a coherent arra~
of a large multiplicity oE optical ~ibers, the diame-ter oE sai~
lens system being no greater than about 120% of the diameter of
said image-earrying member, and said coherent array of fibers
comprising over at least the majority of its length, a drawn and
fused miero-unit in whieh there are of the order of two thousand
ecnstituent fibers that are fused to each other, said miero-unit
having a bend radius of 6 eentimeters or less.
Aeeording to another embodiment of the invention, there
is provided a remote vision miero-optical device in whieh a lens
system of about 0.5 mm diameter and eomprising at least two
substantially spherieal lens surfaees is adapted to deliver an
image into an elongated image-earrying member of generally
eorresponding diameter, the image-earrying member comprised of a
coherent array of a large multiplicity of optical fibers, wherein
said coherent array of fibers eomprises, over at least the
majority of its length, a drawn and fused miero-unit in which
,.i~
, ' - : - ' ' ' ' . ~ ' , , ':
f : ~
~2~7S589
-3- 60412-159
there are of th~ order of two thousand constituent Eibers that are
fused to each other, said micro-unit having a bend radius of 6
centimeters or less, and said drawn, Eused, multi-:Eiber micro-uni-t
comprises glass fibers and has a glass outer surface, and a
polymeric protective outer portion is bonded to -the pristine as
drawn outer glass surface of said micro-unit.
According to another aspect of the invention, such a
remote vision micro-optical device is incorporated within a
cathe~er comprising a sheath defining at least a first lumen and a
second lumen. The first lumen houses the remote vision micro-
optical device and an image-carrying member and the second lumen
defines a working channel for introduction of fluid into a
patient's body.
According to another aspect of the invention, a method
o~ examination of small ducts and vessels of a body, including
such passages as ureters, eustachian tubes, fallopian tubes, small
blood vessels and small passages of the biliary tree~ comprises
introducing into such a passage the remote vision micro optical
: member as described above, and, while moving the micro-optical
member axially in the passage, observing the relationship of the
,~
.: - . - . -
,: - ,,: " ' ' ~ '
.
: - . ~ ' . : :
s~g
-4- 60412-1598
change in position of the instrument in -the body with respec-t to
the zoomed change oE the image of an area of interest along the
wall of the small passage.
According to another aspect oE the invention, an
examination device comprises a hollow metal tube adapted to be
inserted into a body, the tube containing and supporting a remote
vision micro-optical member as described above, with the lens
located in the distal portion of the tube.
~ ccording to a further aspect of the invention a vision
system includes the image-carrying micro-optical member described
above and a handle to which it is adapted to be connected via a
connector, the connector comprising a male member having an
accurately machined surface of revolution adapted to interfit with
a corresponding female receptacle o~ the handle, the axis of the
micro-unit lying on the axis of the surEace o revolution oE the
connector and the axis of the optics of the handle aligned with
the axis of the female receptacle, the end of the male member
having a step to
,~ .
' :' ~ '.
. .
.
~L~t~5S85~
- 5 - 60412-1598
one side of the axis adapted to interfit with a step provided
within the female receptacle.
In preferred embodiments, two axiall~ spaced apar-t
end surfaces are associated with the s-tep, ~n interface bekween
the image-carrying micro-unit and a further imaye-carr~iny
member in the handle being located at one of the end surfaces,
and an interface between a light source and a light guide for
transmitting illumination to the object to be observed by the
lens being located at the other of the spaced apart end surfaces.
According to another aspect of the invention, a
connector system is provided for connecting an image-carrying
member as described above with a handle having associated
optics, comprising a male connector associated with the image-
carrying member and having an accurately machined surface of
- revolution adapted to interfit with a corresponding female
- receptacle of the handle, the axis of the member lying on the
axis of the surface of revolution of the connector and the
axis of the optics of the handle aligned with the axis of the
female receptacle, the end of the male member having a step
to one side o the axis adapted to interfit with a step
provided within the female receptacle, a light guide terminat-
ing upon the step of the male member and being aligned with
a light delivery source within the handle.
According to another aspect of the invention, a
flexible fiberoptic probe useful for the examination of small
ducts and passages, comprises: an eyepiece, a distal lens
.
- . ' ' :
.
: . ~ . ' . . - ,':' ,- '
:
~.2~s5~g
- 5a - 60412-1598
means and the remote vision micro-optical member as described
above, having of the order of 2,000 coherently arranged
fibers, the member extending between the eyepiece and the
distal lens means, the distal lens means having a diameter
of the order of that of the
~. ....
: .
. .
- . ~
'~ " ' ' ,, . ;~ ' :
..
1.27558~
-6- 60412-1598
member and selected to provide a wide angle view in air of about
80 or greater, neutral magnification at a distance selec-ted in
the range o 4 to 8 mm and increasing magnifica-tion at closer
distances down to at leas-t 2 mm.
~ o summarize particularly salient aspects of the
invention, there is provided a multi-fiber micro-unit that may be
employed in a micro-optical system to achieve microendoscopy. Due
to its flexibility, the unit may be used in flexible as well as
rigid imaging-probes. Combined in a micro-optical system with a
correspondingly small optical quality spherlcal lens and closure
window, the multi-fiber unit provides a desirable image, with
resolution down to about 0.001 inch and an ability to view over an
angle of about 80 in air, a distinct advantage in examination oE
- J
. ~
- . :
. . ' :
,, : ' ,
~.27~5~3~
- 7 - 60412-1598
side walls of very narrow passages. The invention also provides
a system for detachably connecting the imaging probe con~aining
the micro-op-tical system with a viewing handpiece containing an
ocular system and illumination light source connections that
achieves precise alignment of image and illumination components~
By this connection system, if the imaging probe is damaged or if
it is desirable to restrict use of a probe to a single patient, it
becomes practical for the physician simply to replace the relative-
ly inexpensive imaging probe, while continuing to use the handpiece
that contains the relatively expensive ocular components.
Other features and advantages of the invention will be
understood from the following description of the presently pre-
ferred embodiments, and from the claims.
Preferred Embodimènt
We first briefly describe the drawings:
Figure 1 is a diagrammatic representation of a process
for forming an image unit of the invention;
Figure la is a representation of another process for
forming an image unit;
Figure 2 is an enlarged side section ~iew of a coating
cup;
Figure 3 is a longitudinal cross-section of a fused
fiber-optic unit made according to the invention;
Figure 4 shows a needle probe image-carrying inspec-
tion device according to the invention while Figure 4a is a much
enlarged end view thereof;
:~
~ .
.
: `
~ . - . ': . . ~ -
75S89
- 8 - 60412-1598
Figure 5 shows a flexible catheter inspection device
according to the invention, while Figure 5a is an end view of the
catheter and Figure Sb is a much enlarged sectional view o~ a por~
tion of Figure 5a containing its fused imaye unit;
Figure 6 is a side view of one embodiment of an
elongated imagingprobe of the invention with the thickness of the
probe exaggerated in size for purpose of illustra-tion;
Figure 7 is a side section view of the distal portion
of the imaging probe of Figure 6, while Figure 7a is an end view
- 10 taken on line 7a-7a of Figure 7;
Figure 8 is an enlarged side section view of the
proximal connector of Figure ~, while Figure 8a is an end view
taken on line 8a-8a of Figure 8;
Figure 9 is a side section view of a viewing handpiece
- for use with the probe of Figures 6-8;
Figure 10 is a plan view of the proximal portion of
another probe embodiment of the invention, while Figure lOa is a
transverse section view taken on line lOa-lOa of Figure 10;
Figures 11 and 12 are somewhat diagra~matic side views
of other embodiments of the distal ends of imaging probes of the
invention;
Figure 13 is a side section view of the distal end
portion of another embodiment of an image-carr~ing probe member,
while Figure 14 is a similar vie~ of the proximal connector
thereof;
Figure 15 is a diagrammatic view of an embodiment
X
-- , : , . :
: - - .. .. :- -:
-
1275~
- 9 - 60412-1598
cf the probe of the invention having varying flexibility, with a
highly flexible distal end; and
Figures 16 and 17 are somewhat diagrammati~ side views
of the distal end portion of embodiments of image units that
enable the realization of the image-carrying member of Figure 15.
Referring to Figure 1, a very large number (typically
of the order of ~,000, e.g., 1,800) of individual glass optical
fibers, each about 0.25 mm or more in diameter and consisting of a
core surrounded by a cladding material of relatively lower index
of refraction, are assembled in coherent array within a bundle 10
and placed within a glass stuffer tube 12 to comprise preform 14.
Tube 12 has an outer diameter of about 40 mm and its material is
selected to be at least compatible with and pre~erably to be the
same as the cladding of the individual fibers. In preferred em-
bodiments, the core, cladding and stuffer tube are all of borosili-
cate glass. By use of glass, especially borosilicate glass, the
clad thickness can be quite thin, allowing high packing and hence
good contrast resolution to be achieved in the micro-unit being
formed. The numerical aperture of glass enables transmission of
a wide angle image, which is of particular importance in examining
the walls of tiny ducts of the body.
In drawing tower 16, the preform assembly 14 is fed
through a heating furnace 18. The preform, including the fibers,
is heated to the softening point, in softening zone 20, and is
then drawn as a unit to decrease the outer diameter to the desired
micro-unit dimension, e.g., to about 0.5 to 1.0 mm (0.020 to 0.040
.
- I .
~2755~3~
- 9a - 60412-1598
inch), or less. By maintaining a proper balance between the
physical properties of the glass and the drawing temperature and
rate, substantially constant tension can be maintained throughout
the length of the formed micro-unit, a condition found to be very
desirable for achieving a high yield rate of satisfactory units.
The drawing action fuses the tiny fibers to one another and fuses
the encapsulating layer to the surrounded optical fibers in a
uniform way so that the resulting image unit is compact, presents
a relatively large active image area for its overall size, and is
flexible due to its small `bend cross-section. The drawn multi-
fiber unit is immediately passed through coating cup 22 containing
the
~.2~;~55E~9
-10- 60~12-1598
relatively opaque coating material 24 that carries an opaque
constituent, described in detail below, so that the pristine, as-
drawn surface o the glass is immedia-tely protected. Referring
also to Figure 2, -the base 26 of the coating cup is in the ~orm oE
a nozzle 28 defining a narrow aperture 30 of length, L, and
diameter, D, selected as described in Panoliaskos, Hallet, and
Garis, "Prediction of Optical Fiber Coating Thickness", APplied
Optics, 24 (15): 2309-2312, Aug., 1985. This cup allows through-
passage of the optical fiber bundle and applies a predetermined
thickness of coating material 24 about the encapsulating layer,
e.g., a thickness between about 0.0005 to 0.002 in~h.
In this way, the pristine surface of the drawn unit is
immediately protected against moisture, pollutants, etc. in the
air to prevent microcracking and the flexibility of the unit is
preserved.
If a second, transparent layer of coating material is
desired, the relatively opaquely coated optical fiber assembly
32'is directly fed to a second coating cup 34 containing a clear
protective coating material 36 of a relative viscosity lower than
that of the relatively opaque coating material 24, e.g., to
prevent mixing of the material o the two layers. The nozzle 38
of coating cup 34 is also sized and dimensioned for through-
passage of the coated fiber assembly 32" with the desired
thickness of clear protective coating material, e.g. .010 inch.
,~
.: , - - -
.
: - - - - , - ..
~27~i 39
-lOa- 60412-1598
Referring to Figure la, a coated optical fiber assembly
32~ e.g. for use in a rigid needle probe or where -the second
transparent layer is not required, is passed -through only a single
cup 22a to apply the relatively opaque layer.
The coated assembly (32', Figure la; 32", Figure 1) is
then cured by passage through ultraviolet chamber
`'''~'
- ' :
~2t~s5~9
- 11 - 60412-1598
40. The U.V. radiation passes into the clear layer (if present)
and cures it, while an adequate amount of the radiation continues
into the thin relatively opaque coating and cures it. Thus there
is formed a solid, nonsticking coating about the fused micro-unit,
this coating permitting handling of the uni-t during manufacture
and serving to protect the unit from damage during use.
In the preferred embodiment, the relatively opaque
coating material is formulated to provide a thin layer containing
sufficient black pigment to substantially absorb light moving
laterally. The preferred coating material includes a photo-
initiator for W curlng, and the level of pigment particles in the
coating layer is controlled to permit sufficient penetration of UV
energy into the coating layer for complete curing.
One particular coating formulation found acceptable
in thicknesses between about 0.0005 and 0.002 inch is as follows:
(a)~ an acrylated urethane oligomer;
(b) a reactive diluent, e.g.
N-vinylpyrrolidone, employed to reduced viscosity of
the urethane and improve flexibility;
(c) a photoinitiator, e.g. a commercial blend of benzo-
phenone and l-hydroxycyclohexyl phenyl ketone; and
(d) a carbon pigment dispersion in monomer.
In the preferred formula, component (a) is about 80 to
85 percent of the mixture, component (b) is about 10 to 15 percent,
component (c~ is provided in sufficient quantity to perform its
nitiation function, being dependent upon the intensity of the
- ' .
.: - , - . ~-., ' , ,.
. ~
.~ :
,- . , .'~
~LZ'7~S~
- 12 - 60412-1598
radiation and speed of draw of the fibers, typically a quantity
about 1 percent, and component (d) is about 1 to 2 percen-t. (All
percentages refer to weight.)
The clear coating, if applied, may comprise the same
components, omitting the carbon pigment.
Referring to Figure 3, without the relatively opa~ue
coating 24 of the invention, a certain portion (indicated by arrows
L) of light traveling, e.g., through an illumination means would
escape laterally and infiltrate clear coating 36, if present, and
clear encapsulating layer 14a. Due to the differing refractive
indices of the adjacent layers, the encapsulating layer 14a, and
the clear coating 36, would act in the manner of wave-guides for
rays haviny a longitudinal component, thus conducting unwanted
light toward the viewer, and presenting distracting halos of light
62 about the image. ~lso, some of the light in layer 14a might
enter the fibers lOa themselves, resulting in a "flare" condition
in the image 58 delivered to the viewer 60, i.e., washing out or
bleaching of the image, with loss o~ contrast.
Such undesirable wave-guiding efects are minimized
according to the invention while preserving the desired small size
of the fiber unit. "Wave-guiding" occurs by repeated reflection
of light as it progresses down a guide, but because of the thin,
relatively opaque coating of the invention, absorption of some
light occurs each time a ray in one of the clear layers strikes
the respective interface with the relatively opaque layer, thus
rapidly decreasing the energy of the ray. In this manner, even
''
~- - , . ' -
- ~ ' ' .
~27~
- 13 - 60412-1598
though light enters the clear layers, substantial longitudinal
transmission oE the light can be defeated.
A micro-optical system ~or viewing in remote areas,
e.g., of -the body, is formed by first assembling a coherent
bundle of about 1,800 borosilicate glass monoflbers (0.026 inch
outer diameter, 0.022 inch core) in a borosilicate glass stuffer
tube, drawing the assembly and coating the pristine surface of the
unit with the relatively opaque coa-ting only, as described above.
The resulting drawn, fused, image unit has an overall diameter
of about 0.020 inch (0.016 inch central active fiber diameter, with
each fiber about 8 micron diameter, 0.00075 inch stuffer tube
drawn thickness, and about 0.0015 inch relatively opaque, U.V.
cured coating thickness) and has a bend radius in the range of
about 1 to 6 cms, preferably about 2 cms or less.
Referring to Figure 7, a tiny, substantially spherical
lens of optical quality, e.g., glass sapphire, or other suitable
optical material is selected to have a diameter close to (no
greater than about 120% of) the diameter of the multi-fiber unit
of bundle 82. A short, rigid, metal tube 84, about 2 to 3 mm
long with an inner diameter of 0.020 inch, is provided with in-
dentations at a predetermined lens-locating position along the
length of the tube. The tiny lens is inserted into the distal end
of this small tube, is advanced proximally until it rests against
the indentations, and is then secured, e.g., with epoxy adhesi~e.
A circular window 88, e.g., glass, sapphire, or other suitable
optical material, is inserted into the distal end of the tube to
..
.
:, ' . ~ , ' . -. ~
~275S89
- 14 - 60412-lSg8
butt against the lens, and is secured in place with epoxy adhesive.
The distal end o the tube is then ground flush with the distal
surface 90 of the window.
The distal end of the coated, coherent multi-~iber
bundle 82 is inserted into the proximal end o~ the tube 84 and
advanced until it butts against the indentations 86. Preferably,
at that point, for optimizing the carried image, ~he assembly
person, while viewing through the system, moves the distal end
surface of the multi-fiber bundle away from engagement with the
indentations until the optimal image is obtained. Unit 82 is then
secured to the tube by epoxy adhesive. (By selection of materials,
properties and the configuration of the elements, this optimizing
step can, in some instances, be omitted, and the multi-iber
bundle secured to the tube in butting engagement with the lens.)
Referring now to Figures 4 and 4a, rigid needle probe
inspection device 42, formed according to the invention, may employ
the lens system of Figure 7. This rigid probe consists of a
stainless steel hypodermic tube 44, e.g.~ 20.0 cm long and about
1.0 mm diameter with a wall thickness of 0.002 inch, or up to 2.0
mm diameter with a wall thickness of 0.005 inch/ an illumination
means 46, an image-carrying optical fiber bundle 48, -formed as
above, having an inner core 50 of optical fibers ~only a few are
shown by way of examplP) surrounded by encapsulating layer 52, the
material of the drawn stuffer tube 12 of Figure 1. The illumina-
tion means is a circumferential, fixed array of illumination-
carrying optical ibers 54 (again only a few are shown~ lying
.
- . -
, . . -- . . .
',
. ~ j , .
'
' . ' ~ .
~2~S5i~3~
- 15 - 60412-1598
closely about the image-carrying bundle, within the hypodermic
tube. About the peripheral surface of the fused imaye unit, be-
tween the light-carrying illumination fibers and the image-carrying
fibers, is disposed the thin, e.g., of the order of about .00~5 to
.002 inch, layer of polymeric, relatively opaque makerial 56 of
the invention. This layer prevents wave-guiding according to the
explanation above.
Referring to Figures 5, 5a and 5b, a viewing catheter
is shown, which may employ the lens system of Figure 7. This
catheter comprises semiflexible fused bundle 64, having a bending
radius, e.g., of about l to 2 centimeters, placed within a lumen
of a flexible, polymeric multilumen catheter 66, e.g., 130 cm long
and 2.0 mm diameter, as shown in Figures 5a and 5b, with
illumination provided by monofilament 68 in a second lumen. The
third lumen provides an open working channel 70. Without protec-
tion of the relatively opaque coating of the invention, the
separation, S, in the catheter between the image-carrying lumen
and the illumination-carrying lumen is so small as to allow in-
filtration o~ light from the illumination means to the fused image
unit and reduction of image quality as described above. Referring
to Figure 5b, the relatively opaque coating 24 of the invention
is disposed between the inner clear encapsulating layer 14a and
the outer ciear protective coating 36 provided for protection of
the bundle. As described above, the relatively opaque layer
attenuates infiltrating light and prevents the inner layer from
acting in the manner of a wave-guide, serving to provide a better
. ~
. ........ , - ' ' ' . - '
.': . . ',
' '
.
~.Z~55139
- 16 - 60~12~1598
image to the viewer.
The fused bundle (in comparison to so-called leached
bundles) has a larger active image area for a comparably sized
unit, i.e., less space between fibers, and in a space-saving way
achieves necessary strength.
Referring now to Figures 6-8, an imaging probe is
shown. It comprises a flexible catheter 92 consisting of a flex-
ible distal sheath 94 of predetermined length, e.g., up to about
10~ cmsl and a proximal connector 96. The sheath, in the embodi-
ment shown, defines a pair of lumens 98, 100, shown in Figures 7
and 8. The first and larger lumen 98 contains the elongated,
image-carrying micro-optical system, including multi-fiber bundle
82 terminating distally in tube 84 which also contains spherical
lens 80, and closure window 88, assembled as described above. The
distal end of the tube 84 extends through and is secured within
sleeve 102 (plastic or metal), which fills the annular cavity
between the tube 84 and the wall 104 of the lumen to seal the end
of the lumen against infiltration of fluid. The second, smaller
lumen 100 contains a light guide 106, e.g., consisting of one or
more fibers, for providing illumination for viewing at the distal
tip
Re~erring to Figures 8 and 8a, the image-carrying
bundle 82 and illumination light guide 106 extend proximally into
male connector 96. The connector has a cylindrical body 108 with
a proximal end portion having a surface of revolution 109 pre-
cisely machined for close-fit within the recei~ing aperture of a
. ~ ~, ~ .. . . . .
. ~. . .
'
- :
~2755E~9
- 17 - 60412-1598
viewing handpiece (Figures 5 and 9), and includes an end step 110
spaced from the a~is of the sur~ace of revolution to match with
a like step in the aperture to facilita-te proper rotational
alignment of the connector within the handpiece. ~he proximal end
of image-carrying bundle 82 terminates at the major surface 112,
e.g., encompassing about 200 of revolution of the proximal end
of the connector, in alignment with the connector axis, A, while
the illumination light guide 106 terminates on the more distal,
minor surface 114. By providing a close tolerance ~it between the
stepped connector surfaces and the corresponding surfaces of the
handpiece, precise alignment of the end face of the image-carrying
bundle 82 with the ocular system 116 in the handpiece and align-
ment of the end face of the illumination member 106 with the path
of illuminating light from the light source 118 is ensured. The
stepped displacement of the connector image surface 112 and
illumination surface 114 from each other also reduces the possibil-
ity of COntaminatiQn of the image from the bundle 82 by errant
illumination light directed toward the light guide 106. The body
of the connector has a radial flange 120 to aid the operator in
rotation and insertion; and also removal, of the connector. The
body also defines a circumferential groove 122 for receiving an
O-ring 124, which provides a liquid-~ight seal when the connector
is assembled with the handpiece.
The fiberoptic viewing handpiece 126, seen diagrammati~
cally in Figure 5 and in section in more detail in Figure 9,
consists of a body 128 defining a distal connector-recei~ing
~,,~. .
~ ,;
' :.` ~' ' ', j ' . '. - :
.'. ' - ,
.
~Z755~3~
- 18 - 6o4l2-l598
aperture 130 and containing ocular system 116 for viewing through
the image-carrying micro-optical system. Extending below the
handpiece body is a handle 132, which terminates in a connection
to an illumination light-carrying cable 134 from a light source
(not shown). Light from the source is directed into reflector 136,
a half sphere, silvered on the planar reflective surfaces and on
the spherical surface except for two appropriate apertures, the
reflective surfaces acting as stray light traps. The proximal
connector 96 of the imaging probe 92 is inserted into aperture 130
with close fit, the step-form of the connector requiring proper
rotational orientation, facilitated by beveled surface 138, before
full insertion is achieved. Once inserted, the connector is se-
cured by tightening knob 140.
Other embodiments of the invention are within the
claims. For example, to further reduce the overall diameter of
the device, the diameter of the encapsulating layer may be reduced
by eliminating the stuffer tube and assembling the fiber bundle
by other means, e.g., by use of a glass frit bonding material at
- least compatible with the cladding material of the individual
~ibers, the frit forming a relatively thinner encapsulating layer
during the drawing step. Also, a relatively opa~ue coating may be
cured thermally or catalytically, or by use of an infrared heater,
although in the semiflexible, dual-coated optical fiber bundle
shown, this would occur before application of the second, clear
protective coating, which would then typically be cured by exposure
to UV radiation.
.~ :
. .
.
- - . : -
.
-
: ' ' . ~ ' '
,
- .
~75S~3~
- 19 - 60412-1.5g~
The sheath may define more than one open working chan-
nel, e.g., for introduction of fluid for flushing or irrigating
or for dilatation of the duct surrounding the distal end of -the
probe or increased field of view, or for use of a guidewire or
other instruments such as retrieval baskets or forceps. Referring
to Figures 10 and lOa, an imaging probe 138 has a single working
channel140, terminating proximally in leur connection 142. The
working channel may also be employed for flow of fluid for inflation
and deflation of a balloon 144 adjacent the distal end of the
catheter 146, e.g., proximal of the viewing lens 148 ~Figure 11),
or about the tip, with the image received through the balloon 144'
(Figure 12). Also, referring to Figures 13 and 14, the illumina-
tion light guide 106' may be in the form of a plurality of fibers
which are disposed about the image-carrying bundle 82 within the
connector 96' and extend within the catheter sheath 94', alongside
the bundle, as shown in Figure 4a, and the distal tube 84, to
terminate distally in a halo-like array about the image-receiving
closure window surface 90.
Referring to Figures 15, 16 and 17, a catheter with
increased flexibility at the distal tip region is shown, e.g., to
provide a tip bend radius, Rl, e.g., of the order of about 2 cms
or less, as compared to a larger bend radius, R2, of the body of
the probe 149. The more flexible distal end ser~es to facilitate
negotiation of small radius bends in passages of the body, e.g.,
a 90 turn into the coronary artery. For this purpose, in Figure
16, the fused bundle 82" is comprised of a leachable (or water
- . . ~ . - .
- - ~ . . ,
- ' ~ .
~.~75S~3~
- 20 - 60412-1598
soluble) stuffer tube and the fibers include a similarly leachable
second clad, known as a super cladding. The drawn and fused unit
may be selectively leached over a limited distal length as shown
in the figure to remove the leachable stuffer tube and a leachable
super cladding on individual fibers over a length, L, e.g., of
about 5 to 10 cms. The exposed, pristine, separated individual
fibers are then lubricated, e.g. with carbowax, silicone oil or
the like, and encased within a jacket 152. In Figure 17, the
fused bundle 82' may be selectively drawn down to a smaller dia-
meter, Dl, e.g., 75 to 85% of the original diameter, D2, over a
length, L, e.g., 5 to 10 cms. The outer surface of the reduced
diameter segment may be immediately recoated in the manner describ-
ed above, or the coating may be sufficienly flexible to be drawn
with the bundle, without need for recoating. Alternatively, a
fused bundle may be selectively treated, e.g., by tempering, to
achieve segments of relatively greater flexibility.
Where desired, the micro-optical viewing system of the
invention enables introducing the distal end of the imaging probe
into the body percutaneously, i.e., via a small puncture opening,
and advancing the probe tip while viewing via the eyepiece. The
flexible imaging probe has particular application to examination
of small diameter ducts and passages of the body, e.g., the ureter
(2 mm diameter typical), the biliary tree (4 mm), eustachian tubes
(2 mm or less), the Fallopian tubes (1.5 to 2 mm) and blood
vessels, e.g., the coronary arteries (2 to 4 mm diameter typical).
The overall diameter of the imaging probe cantaining the micro-
- ~ . ,
- - - ,: :
'
.
ss~
- 21 - 60~12-1598
optical viewing system, its length and the provision and siYe
of its open lumens is dependent upon the procedure to be performed.
By way of example only, the following charac-teristics may be
employed:
Overall Open Lumens
Diameter Length
Description (mm) - (cm) Number Diameter(s)
ureteral 2.8 60 2 .018 inch
visual catheter .042 inch
direct visual 4.3 60 1 2.6 mm
lavage of
pulmonary system
endotracheal tube 2.2 60-Adult
visual catheter 40-pediatric .042 inch
biliary catheter 2.0 60 2 .010 inch
angioscope 1.2 100 -- --
eustachian tube 1.2 23 -- --
visual catheter
Rigid embodiments of the imaging probe may also be
used percutaneously, e.g., for visual examination of the li~er,
biliary tree, pancreatic duct and short vessels, and also for
examination of joints and the spine.
By selection of the components of the micro-optical
system, i.e., the multi-fiber fused bundle, along the lines
mentioned above, and the optical quality of the spherical lens
and closure window, there is provided a viewing system particular-
ly suited for medical examination.
To examine a point in the body employing the imaging
probe of the invention, the physician introduces the distal tip
of the imaging probe into the body and, while viewing through the
? ~
" ' ''.. "' .' .
. , . : :
': ' ' ' - ' ' ' ': ,,
.
'
~.275~89
- 21a - 60412-1598
eyepiece (152, Figure 9), moves the distal tip toward and away
from the point he wishes to examine, observing the relationship
of the distance of movement of the probe in the body with respect
to the change of the viewed image. In the preferred e~bodiment
described, objects viewed at a range oE about 4 to 8 l~m, and pre~
ferably about 5 to 5 mm, from the distal surface 90 are seen at
about actual size, while objects seen from about 5 to 6 mm down
to about 1 mm are seen with increasing magnification, the closer
the distance, and objects beyond about 5 to 6 mm (to infinity
theoretically, although the practical maximum range in the body is
about 15 to 20 mm) are seen with decreasing size, the longer the
distance. The result during movement of the catheter is a zoomed
effect, with a much improved image, likened to taking a zoom micro-
scope into the body, that provides resolution down to abou-t 0.001
inch. Thus the invention includes the realization that distortion
of such a lens, rather than a detriment, can be used in a highly
constructive way.
The relatively high quality of the image achieved may
be attributable to a kind of field flattening effect caused by the
pin hole principle, due to the small size of the micro-unit. Also,
the spherical aberration of ~he created image, attributable to
the spherical lens 80, provides an added advantage in examining
the walls of small passages, in which it would not be possible to
obtain a head-on inspection. The side view of the passage wall
is presented to the eye as a somewhat expanded, and flattened image,
format that is convenient to examine, with appearance some~hat
:'~
, . . , ~: , , ,:
.
~.~7S5~9
- 21b - 60412-1598
resembling the mercator projection used in map making.
In the case of the wall of a narrow passage, the wide
angle optical system has the effect of bending the magnified
position of the tube wall toward thé viewer to enable a detailed
examination despite the end on relationship of the probe to the
passage. By slight adjustment of position, the operator may
shift from microscopic to actual scale view of the same area, and
~,
.
- : . .
. ~ . .
.~ . . . .
I
,
,
~Z7S5B9
-22- 60412-159
thus in real time may assemble a great deal o~ meaningul optical
information concerning a region o interest within the body.
Finally we mention that certain principles o the
invention related to the coated multi-fiber micro-unit per se can
be applied to noncoherent light-transmitting fused iber bundles
with benefit in appropriate circumstances.
.:' ''~ . - :
, ' . ~ ,~ '
,. . , ~ .
,
- . .
