JP4067178B2 - Laser beam irradiation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser beam irradiation apparatus for irradiating a laser beam from a distal end portion of a main body that can be inserted into a body cavity such as a catheter, and more particularly to a laser beam irradiation apparatus for performing laser ablation treatment or examination.
[0002]
[Prior art]
Conventionally, various devices have been developed for the purpose of cauterizing a lesion such as a cancer or a tumor that has occurred inside a body cavity. Among these, for example, Japanese Patent Laid-Open Nos. 4-285550 and 5-237132 disclose ones that change the irradiation direction of laser light using a shape memory material.
[0003]
These devices irradiate laser light in a target direction by bending the optical fiber that guides the laser light, for example, by the deformation force of the shape memory alloy and changing the direction of the tip (exit end). is there. If these apparatuses are used, the direction of the laser light emitting end of the optical fiber can be controlled, and a laser beam can be irradiated to a predetermined part.
[0004]
[Problems to be solved by the invention]
In these conventional apparatuses, the optical fiber itself is bent in order to change the laser light irradiation direction. However, the optical fiber cannot be bent smaller than the minimum radius of curvature, and the bending angle is greatly limited in a narrow space such as a body cavity, particularly in a vessel, so that the laser beam is directed to the side in the insertion axis direction. It was difficult to use.
[0005]
In the present invention, laser light irradiation can be switched between the front and side of the insertion portion, and the inner wall of the luminal tissue around the insertion portion can be irradiated even in a narrow space such as in a hollow organ or a vascular vessel. An object is to provide an irradiation apparatus.
[0006]
In the present invention, the laser beam can be irradiated and scanned from the front side to the side of the insertion portion, and the mechanism for irradiating and scanning the laser beam into the body cavity can be made simple and small. An object of the present invention is to provide a laser beam irradiation apparatus that is light in weight and highly reliable.
[0007]
[Means for Solving the Problems]
Such an object is achieved by the following inventions (1) to (5).
[0008]
(1) It has a long insertion part, a light guide means for guiding laser light in the insertion part, and a laser light reflection means provided near the tip of the insertion part, the laser light reflection means provided with a cantilever made of a flat plate shape forming a shape memory alloy and the reflective surface, further comprising a heating means for deforming by heating the cantilever, have a tip cap to the laser light is transmitted to the distal end of the insertion portion, The cantilever is capable of irradiating a laser beam in an arbitrary direction between an axial direction and a front side in a lateral direction in accordance with a temperature generated by heating of the heating unit.
[0009]
(2) The laser beam irradiation apparatus according to (1), wherein the cantilever is an omnidirectional shape memory alloy.
[0010]
(3) The laser beam irradiation apparatus according to (1), wherein the cantilever is a bidirectional shape memory alloy.
[0011]
(4) The laser according to (1), wherein the cantilever is a unidirectional shape memory alloy, and the laser light reflecting means further includes a bias spring material that applies a force to bend the cantilever. Light irradiation device.
[0012]
(5) The laser beam irradiation apparatus according to (1), further comprising cooling means for supplying and discharging a cooling fluid around the cantilever.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the laser beam irradiation apparatus of the present invention will be described in detail with reference to the preferred embodiments shown in the accompanying drawings.
[0014]
1 and 2 are diagrams for explaining the configuration of the tip of the laser beam irradiation apparatus according to the present invention. FIG. 1 shows a state in which the laser beam is irradiated to the side, and FIG. The state of irradiating forward is shown. 3 is a front view of the state of FIG. 2 and its AA sectional view, and FIG. 4 is a front view of the state of FIG. 1 and its BB sectional view.
[0015]
1 to 4, the laser light irradiation device 1 emits laser light generated from a laser light source (not shown) connected to the proximal end of the laser light irradiation device 1 inside a catheter 2 that is an insertion portion into a body cavity. An optical fiber 3 for guiding light is inserted, and a distal end cap 4 made of a light transmissive material such as acrylic resin or quartz is attached to the distal end of the catheter 2 so that laser light can pass therethrough.
[0016]
The cantilever 5 is an actuator made of an omnidirectional shape memory alloy, and a reflective surface 6 is provided on the surface of the cantilever 5 irradiated with the laser light so that the laser light can be efficiently reflected. Further, a lead wire 7 for energization is provided as a heating means so as to be connected to the cantilever 5. By passing an electric current through the lead wire 7 to the cantilever 5, the shape memory alloy itself self-heats and a heat quantity necessary for deformation is obtained.
[0017]
A collimating lens 8 is provided at the laser light emitting end of the optical fiber 3. In a normal optical fiber, the emitted laser light spreads at an opening angle (around 40 degrees) determined by the refractive index of the core of the optical fiber. In this case, not only a part of the emitted laser beam reaches the reflection surface, but also the profile of the laser beam after reflection is significantly lowered. The collimating lens 8 is for suppressing the diffusion of laser light as much as possible and emitting convergent light.
[0018]
The diameter of the exit end of the optical fiber 3 with the collimating lens 8 attached is 1.5 mm, and the size of the reflecting surface 6 provided on the cantilever 5 is 1 mm × 1 mm. These are the outer diameters (diameters). Built in a 3 mm catheter 2.
[0019]
The catheter 2 is formed to have a gap around the optical fiber 3, and the surrounding gap can act as an air supply lumen 10a and an exhaust lumen 10b. A partition wall 11 is formed in the inner hole of the catheter 2, and the partition wall 11 separates the air supply lumen 10 a and the exhaust lumen 10 b while fixing the optical fiber 3. Through these lumens 10a and 10b, carbon dioxide gas is circulated as a cooling fluid from a cooling fluid circulation device (not shown) from the proximal end of the catheter 2. The carbon dioxide gas used for cooling the apparatus only flows through the inside of the catheter 2 and does not leak out of the catheter 2.
[0020]
When the cantilever 5 is not energized by the lead wire 7 (there is no heating), the cantilever 5 is in a state of extending straight as shown in FIG. The reflecting surface 6 is completely out of the irradiation range of the laser beam (FIG. 3), and in this state, the laser beam is irradiated in the direction of the distal end in the catheter axial direction (forward).
[0021]
When a current is passed through the lead wire 7 to self-heat the shape memory alloy and the temperature is gradually raised, the cantilever 5 intersects the optical axis of the laser beam at about 45 degrees as shown in FIGS. Shape. In this embodiment, the temperature at this time is about 80 ° C. However, since the heating is very local in the vicinity of the cantilever 5, it is not heated to the outside of the catheter 2. At this time, when the state where the exit end of the optical fiber 3 is viewed from the distal direction of the catheter 2 is illustrated, the exit end of the optical fiber 3 is hidden behind the reflecting surface 6 of the cantilever 5 as shown in FIG. It becomes. The laser light is reflected by the reflecting surface 6 and as a result, is emitted 90 degrees laterally from the axis of the catheter 2.
[0022]
In this embodiment, since the omnidirectional shape memory alloy is used as the shape memory alloy, the cantilever 5 can take an arbitrary angle between the state of FIG. 1 and the state of FIG. 2 according to the temperature by heating. At this time, the laser light is emitted in an arbitrary direction between the front and side in the axial direction of the catheter 2.
[0023]
When the energization by the lead wire 7 is stopped and the heating is stopped, the shape memory alloy is rapidly cooled by the flow of carbon dioxide gas vented through the lumen of the catheter 2, and accordingly, the shape memory alloy is cooled at room temperature. Return to shape (straight). Since the temperature of the cantilever 5 can be rapidly lowered by this air cooling, the cantilever 5 can be quickly returned to the normal temperature angle as compared with the case of natural cooling, thereby improving the scanning speed of the laser beam. I can do it.
[0024]
Here, the laser beam emitted from the catheter 2 to the outside can be scanned by intermittently energizing the lead wire 7. Moreover, when it is desired to fix the irradiation in a certain direction, the energization amount may be adjusted so that the temperature of the shape memory alloy becomes constant.
[0025]
In this embodiment, an omnidirectional shape memory alloy is used as the shape memory alloy, but a bi-directional shape memory alloy can also be used. Bidirectional shape memory alloys can be held by a cantilever only in two specific angles (usually straight and 45 degrees to the laser beam), and hold any angle between them. However, other than that, it can be used for laser light irradiation with the same mechanism.
[0026]
Furthermore, a unidirectional shape memory alloy is used as the shape memory alloy, and a bias spring material that applies a force for curving the same is laminated on the cantilever, and a combined structure can also be used. If comprised in this way, two angles, the angle of the cantilever obtained when the cantilever is bent by the bias spring and the angle of the cantilever stored by the shape memory alloy when heated by the heating means, can be obtained. Therefore, the angle at which the laser beam is incident on the reflective surface on the cantilever changes depending on the degree of heating, and the laser beam can be irradiated in two directions.
[0027]
The shape memory alloy used for the cantilever 5 is preferably a NiTi alloy, a Cu—Zn—Al alloy, or the like. Further, the transformation point of these shape memory alloys is preferably about 40 to 80 degrees. The transformation temperature should be selected such that heat does not leak out of the catheter 2 and that there is no possibility of deformation when not warmed.
[0028]
The reflective surface 6 can be obtained by forming a metal thin film on the surface of the cantilever 5 via an electrical insulating film. Specifically, a reflective surface with high reflectivity can be suitably obtained by depositing a metal such as Al, Ti, Pt, or Au. Further, the shape memory alloy itself can be used as a reflective surface by mirror-treating the surface of the shape memory alloy.
[0029]
The embodiments of the present invention described above are described for easy understanding of the present invention, and the present invention is not limited to the embodiments. Therefore, each element disclosed in the above embodiment includes all design changes and equivalents belonging to the technical scope of the present invention.
[0030]
For example, in the present embodiment, the case where the laser light irradiation apparatus according to the present invention is used in a laser ablation treatment or inspection scene using a catheter has been described. You may apply to.
[0031]
【The invention's effect】
As described above, according to the present invention, since the scanning of the laser beam to the lesion is realized by the angle change of the cantilever driven by the shape memory alloy, the body of the catheter inserted into the body cavity is moved. It is possible to irradiate the laser beam to a certain range. That is, it becomes possible to scan and irradiate laser light even in a narrow space such as in a luminal organ, so that treatment and examination with laser light can be performed efficiently and safely.
[0032]
In addition, because the shape memory alloy itself is used for heating the shape memory alloy, there is no need to provide a heater for heat generation separately, and there is no internal loss that causes the heater to bend and deform. A driving force can be obtained. In addition, since the laser beam scanning mechanism is very simple and compact, a catheter with a built-in laser beam irradiation device can be used with a small diameter, reducing the physical burden on patients undergoing treatment and examination. It becomes possible to do.
[Brief description of the drawings]
FIG. 1 is a perspective view of a tip portion showing an embodiment of a laser beam irradiation apparatus of the present invention.
FIG. 2 is a perspective view of a tip portion showing an embodiment of a laser beam irradiation apparatus of the present invention.
3 is a front view and a side sectional view of the state of FIG.
4 is a front view and a side cross-sectional view of the state shown in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laser beam irradiation apparatus 2 Catheter 3 Optical fiber 4 Tip cap 5 Cantilever 6 Reflective surface 7 Lead wire 8 Lens

Claims (6)

A long insertion portion; a light guide means for guiding laser light in the insertion portion; and a laser light reflection means provided in the vicinity of the distal end of the insertion portion. The laser light reflection means has a flat plate shape. and a formed shape memory composed of an alloy cantilever and the reflective surface, further comprising a heating means for deforming by heating the cantilever, have a tip cap to the laser light is transmitted to the distal end of the insertion portion, the cantilever The laser beam irradiation apparatus can irradiate the laser beam in an arbitrary direction between the axial direction and the front in the lateral direction in accordance with the temperature of the heating means . 2. The laser light irradiation apparatus according to claim 1, wherein the heating means is means for generating self-heating by energizing the shape memory alloy. 3. The laser beam irradiation apparatus according to claim 1, wherein the cantilever is an omnidirectional shape memory alloy. 3. The laser beam irradiation apparatus according to claim 1, wherein the cantilever is a bi-directional shape memory alloy. The said cantilever is a unidirectional shape memory alloy, The said laser beam reflection means further has the bias spring material which applies the force which curves the said cantilever, The Claim 1 thru | or 2 characterized by the above-mentioned. Laser light irradiation device. 6. The laser beam irradiation apparatus according to claim 1, further comprising cooling means for supplying and discharging a cooling fluid around the cantilever.

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