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Description  |
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BACKGROUND OF THE INVENTION:
1. Field of the Invention:
The present invention is directed to a laser treatment apparatus for
guiding a laser beam through an optical fiber for the incision,
vaporization or coagulation of a target tissue, or for photochemical
therapy.
2. Description of the Prior Art:
A well-known laser apparatus for medical treatment has a typical
construction depicted in, e.g., FIGS. 8 and 9.
A fiber waveguide member generally designated at 1 includes a core portion
2 and a clad 3. Core portion 2 assumes a substantially circular
configuration in cross section and is formed of a light-transmitting
material having a low thermal conductivity and a high heat-resistant
property such as silica glass or potash glass. Clad 3 is formed on the
outer periphery of core portion 2. An output end of core portion 2 is so
cut off as to have a surface perpendicular to the optical axis, and is
then ground. An input end on the opposite side of core portion 2 is
connected to a laser beam source 4. Coaxially provided on the outer
periphery of fiber waveguide member 1 is an external tube 6 having a
spatial portion 5 serving as, for instance, a water or air passageway.
Fixed to the tip of external tube 6 is a holding member 8 formed with an
insertion hole 7 into which fiber waveguide member 1 is inserted. An
optical connector 9, which is connected to laser beam source 4, is
provided at the input end of external tube 6. There is further formed a
branch tube 10, the interior of which communicates with spatial portion 5
for sending a liquid or gas to external tube 6. The liquid or gas is fed
in from the end of branch tube 10.
The laser beams from laser beam source 4 are led via fiber waveguide member
1 and are then emitted from the output end of the tip of fiber waveguide
member 1. At this time, living tissues organized at spacings of several
millimeters are irradiated with the laser beams at divergent angles of
approximately 8.degree.-12.degree. from the output end of fiber waveguide
member 1. On the occasion of irradiation, the irradiation surfaces may be
damaged by contaminant such as tissues, tissue liquid and smoke emitted by
their vital reaction. With a view to preventing this damage, an assist gas
or water is sent from branch tube 10 via spatial portion 5 to the tip
output end of fiber waveguide member 1, thereby eliminating the
contamination on the output end.
In fact, however, the contamination on the tip end portion can not
sufficiently be prevented, depending on the assist gas or water, and the
tip end portion is burnt, thereby causing a damage. In order to adjust the
divergent angles of laser beams to the purposes of medical treatment, in
some cases the tip output end of fiber waveguide member 1 is shaped in a
conical or semispherical configuration, but it can easily be damaged by
the contamination or diffused rays of light.
FIG. 10 illustrates a known fiber treatment apparatus which effects the
medical treatment by directly touching the living. This type of apparatus
is arranged such that the tip of holding member 8 of the laser treatment
apparatus depicted in FIG. 8 is fitted with a connector 11 connected to a
tip member 12 formed of a light-transmitting material like, e.g.,
artificial sapphire (.alpha.-Al.sub.2 O.sub.3), tip member 12 being so
secured to the axis of fiber waveguide member 1 as to be spaced therefrom.
Formed in the cylindrical portion of connector 11 around the spacing
between tip member 12 and fiber waveguide member 1 are discharge holes 13
from which the assist gas or water is discharged.
There arises, however, the following problem inherent in the laser
treatment apparatus depicted in FIG. 10. The apparatus is in contact with
the tissues, and hence a contaminant permeates from discharge hole 13 and
contaminates the optical axis of tip member 12 as well as fiber waveguide
member 1. This results in damage to fiber waveguide member 1 and tip
member 12 due to the burnt loss associated with the contaminant by the
laser beams.
As described above, the laser treatment apparatus illustrated in FIG. 8 is
attended with the problem that the tip end surface of fiber waveguide
member 1 undergoes burning due to contamination, resulting in the damage
to fiber waveguide member 1.
The laser treatment apparatus also has the problem in which the optical
axis positioned in the spacing between fiber waveguide member 1 and tip
member 12 is contaminated and undergoes the burning, with the result that
the fiber waveguide member 1 and tip member 12 are damaged.
In either case, the contamination has to be eliminated and it is further
required that fiber waveguide member 1 be cooled down by using the assist
gas or water. Hence, these laser treatment apparatuses are not allowed for
use in such places that the assist gas or water can not be employed.
SUMMARY OF THE INVENTION
It is therefore a primary object of the present invention to provide a
novel laser treatment apparatus which is hard to be damaged.
According to one aspect of the invention, there is provided a laser
treatment apparatus characterized in that a tip member formed of a
light-transmitting material having a low thermal conductivity and a high
heat-resistant property is integrally welded to the tip portion of a fiber
waveguide member connected to a laser beam source.
According to another aspect of the invention, there is provided a laser
treatment apparatus characterized in that a connecting portion having
substantially the same diameter as that of a core portion of a fiber
waveguide member is integrally formed on a tip member, and end surfaces of
the connecting portion and of the core portion are integrally welded to
each other.
According to still another aspect of the invention, there is provided a
laser treatment apparatus characterized in that a fiber waveguide member
includes a core portion and a clad formed on the circumference of the core
portion, and a cladding part leading to the clad is formed on the outer
peripheries of a connecting portion of a tip member and of a welded
portion between an end surface of the connecting portion and an end
surface of the core portion.
According to a further aspect of the invention, there is provided a laser
treatment apparatus characterized in that external portions of a fiber
waveguide member and of a tip member are connected to each other through a
sleeve.
According to a still further aspect of the invention, there is provided a
laser treatment apparatus characterized in that a fiber waveguide member
and a tip member are formed into one united body by welding, and laser
beams emerging from a laser beam source are emitted out of the tip member
via the fiber waveguide member.
According to yet another aspect of the invention, there is provided a laser
treatment apparatus characterized in that a welding process is facilitated
by integrally welding an end surface of the fiber waveguide member to an
end surface of a connecting portion formed on a tip member.
According to a yet further aspect of the invention, there is provided a
laser treatment apparatus characterized in that a cladding part leading to
a clad is formed on the outer peripheries of a connecting portion of a tip
member and of a welded portion between an end surface of the connecting
portion and an end surface of a core portion of a fiber waveguide member,
thereby minimizing damages caused by a leakage of light and contamination.
According to a still additional aspect of the invention, there is provided
a laser treatment apparatus characterized in that the external portions of
a tip member and of a fiber waveguide member are connected to each other
and reinforced by use of a sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS:
Other objects and advantages of the invention will become apparent during
the following discussion in conjunction with the accompanying drawings, in
which:
FIG. 1 is a side view with parts partially broken away, illustrating one
embodiment of a laser treatment apparatus according to the present
invention;
FIG. 2 is a side view showing a state where the laser treatment apparatus
is used;
FIGS. 3 to 5 are side views with parts partially broken away, respectively
illustrating other embodiments thereof;
FIG. 6 is a side view with parts partially broken away, showing still
another embodiment;
FIG. 7 is a side view illustrating a state where the laser treatment
apparatus of FIG. 6 is used;
FIG. 8 is a sectional view depicting a conventional laser treatment
apparatus;
FIG. 9 is a side view showing a state where the prior art apparatus is
used; and
FIG. 10 is a sectional view showing another example of the prior art
apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
In FIGS. 1 and 2, the same components as those depicted in FIGS. 8 to 10
are marked with the like symbols.
A fiber waveguide member generally indicated at 1 includes a core portion 2
which assumes a substantially circular configuration in cross section and
has a diameter of 100-600 .mu.m. Core portion 2 is formed of a
light-transmitting material having a low thermal conductivity and a high
heat-resistant property such as silica glass (SiO.sub.2) or potash glass.
Fiber waveguide member 1 also includes a clad 3 formed of an organic
material such as silicone having a different refractive index from that of
core portion 2. The outer periphery of core portion 2 is covered with clad
3 which is approximately 3-4 m in length.
A tip member 12 is formed of the same material as that of core portion 2 of
fiber waveguide member 1. An output end of a body 14 is formed integrally
with a laser beam irradiation part 15 assuming a substantially cylindrical
shape. An incident end of body 14 is also formed integrally with a
cylindrical connecting portion 16 having almost the same diameter as that
of core portion 2.
Clad 3 provided at the tip portion of fiber waveguide member 1 is stripped
by several millimeters to integrally weld the tip end surface of core
portion 2 and the incident end surface of connecting portion 16, thus
shaping a welded portion 17. A bonding agent conceived as a cladding
material is coated on the outer peripheries of welded portion 17,
connecting portion 16 and core portion 2 from which clad 3 is partially
stripped so that the coating level is nearly flush with the outer surface
of clad 3, thus forming a cladding part 18.
Fixed to the outer periphery of fiber waveguide member 1 is the inside of
the proximal end of a metallic sleeve 19 formed in substantially
cylindrical configuration. The inner periphery of tip portion of sleeve 19
is also fixed to the outer periphery of body 14 of tip member 12, thereby
reinforcing the connection between fiber waveguide member 1 and tip member
12.
Connected to the proximal end of fiber waveguide member 1 is an optical
connector 9 by which a laser beam source 4 is connected to core portion 2
of fiber waveguide member 1.
The laser beams emitted from laser beam source 4 are led by core portion 2,
and the irradiation of laser beams is effected by a laser beams
irradiation part 15 of tip member 12. Then, the tissues of a living are
subjected to an incision, vaporization and coagulation or a photochemical
therapy.
In the illustrative embodiment described above, the light-emitting end
surface of core portion 2 of fiber waveguide member 1 is integrally welded
to the light-entering end surface of connector 16 of tip member 12. With
this arrangement, the light-emitting end surface of core portion 2 and the
light-entering end surface of connecting portion 16 are not contaminated
with contaminants such as blood or the like. Damage due to burning is thus
prevented.
In applying the cladding material, it will not flow and deposit on the
light-emitting end surface of core portion 2 and on the light-entering end
surface of connecting portion 16.
The cladding material is applied on the outer peripheries of connecting
portion 16, welded portion 17 and the portion from which clad 3 is
stripped, thus forming cladding part 18 sealed by sleeve 19. Based on this
arrangement, it is feasible to prevent a leakage of light and permeation
of contaminants into gaps such as pinholes of cladding part 18. Therefore,
the possibility of causing the damages due to burning associated with the
contamination can completely be eliminated.
Hence, when laser beams irradiation part 15 of tip member 12 is brought to
the seat of a disease in which the light-emitting end tends to be
contaminated in a clinical use, the probability of being damaged is small.
Besides, the disease seat in which a flow of assist gas or water is not
permissible can be treated.
The laser beam irradiation part of tip member 12 may assume arbitrary
shapes such as a semispherical configuration illustrated in FIG. 3, or a
frust-conical shape in which the tip is, as illustrated in FIG. 4, formed
in a spherical configuration, or a conical shape shown in FIG. 5. The
angles at which the laser beams are emitted may arbitrarily be set
depending on the configuration of tip member 12.
In accordance with the above-described embodiments, laser beam irradiation
part 15 can be shaped by rotating tip member 12 without rotating lengthy
fiber waveguide member 1.
Furthermore, a member such a spring may be employed instead of metallic
sleeve 19.
The description will next be focused on a further embodiment with reference
to FIGS. 6 and 7. Provided through a spatial portion 5 on the outer
periphery of fiber waveguide member 1 is an external tube 6 having its top
end to which a connecting cylinder 20 is connected. The outer periphery of
the body 14 of tip member 12 is fixed to the inner peripheral portion of
top of connecting cylinder 20 perforated with a discharge hole 13 through
which the cylinder interior communicates with the cylinder exterior. A
branch tube 10 extending from external tube 6 admits an inflow of assist
gas or water.
In the disease seat which does not permit the use of assist gas or water,
as in the embodiment shown in FIGS. 1 and 2, the laser beams emerging from
laser beams source 4 are led by core portion 2 of fiber waveguide member
1, and the irradiation thereof is effected by laser beams irradiation part
15 of tip member 12 without using the assist gas or water.
In the disease seat wherein the assist gas or water is allowed to be
employed, if the cooling of fiber waveguide member 1 is needed, the assist
gas or water is fed in from branch tube 10 and is then transmitted via
spatial portion 5. Fiber waveguide member 1 and tip member 12 are thus
cooled down.
In accordance with the embodiment of FIGS. 6 and 7, the laser treatment
apparatus can be used under such circumstances that there exist
contaminations in the tissue liquid or blood, or a sufficient cooling
function is not provided in the air.
As discussed above, the present invention exhibits the following effects.
The tip member is welded to the top end of the fiber waveguide member,
thus forming the fiber waveguide member and the tip member into one united
body. This arrangement prevents the contamination on the laser beam axis,
thereby causing no burning, which in turn reduces the damages to the tip
member.
The connecting portion of the tip member has almost the same diameter as
that of the core portion, thereby facilitating the welding process.
In addition, the cladding part leading to the clad is formed on the outer
peripheries of the welded portion as well as of the connecting portion. As
a result of this arrangement, the leakage of light can be decreased, and
the connecting strength increases. Hence, the efficiency of laser beams
can be ameliorated. Moreover, a situation is present wherein damages are
hard to occur.
The fiber waveguide member is fixedly connected to the tip member by means
of the sleeve, and the connection between the fiber waveguide member and
the tip member can thereby be reinforced. Consequently, even if the tip
member is separated from the fiber waveguide member, the tip member can be
held by the sleeve. The treatment can thus be performed under safety
conditions.
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