JPH0910222A - System for irradiating living body with laser beam - Google Patents

Abstract

PURPOSE: To lessen the damage on a tissue section which is not a section to be treated by providing the system with a target means for using a section where a material to generate heat by absorbing a laser beam is made to exist in the vital tissues as the target and a means for irradiating the target with the laser beam which generates the heat by irradiating the target with the laser beam. CONSTITUTION: The target zone 20 is formed by injecting a dispersion contg. an exothermic material in the prescribed section in the tissues M. A supplying conduit 14 and a drain conduit 16 are opened into a flow chamber 18 enclosed by a guide window 12 and a partition wall 10A at the front end of a holder 10. The target zone 20 is concentrically heated and the transpiration and solidification of the tissues in the part arise when the target zone 20 is irradiated with the laser beam L in the process of continuously or intermittently passing water W into the flow chamber 18 using the laser beam irradiation device. The temp. from the tissue surface to the target zone in this section is low and the damage of the tissues in the part is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for irradiating a living body with laser light. In particular, the present invention relates to a laser light irradiation system that enhances the absorption efficiency of laser light in a target portion in a living tissue and has excellent therapeutic effects.

[0002]

2. Description of the Related Art In recent years, it has been widely used to irradiate a living tissue with a laser beam to incise, evaporate, coagulate or heat the tissue.

In this case, in addition to the non-contact method in which a laser beam is directly emitted to a living tissue from an optical fiber positioned away from the living tissue, for example, US Pat. No. 4,736,743 relating to the present inventor's invention is disclosed. As shown, a light guide probe is provided in front of the optical fiber, and laser light is emitted to the living tissue in a state where the light guide probe is in contact with the living tissue, so-called contact method is often used. There is.

In the patent, there is also a means for forming a layer containing a heat-absorbing powder on the tip of a probe and converting the energy of laser light into heat energy to favorably dissect and coagulate tissue. It is disclosed.

This contact method allows the probe to be accurately positioned with respect to the target site, and
There is an advantage that the amount of laser light incident on the tissue can be accurately controlled.

[0006]

The energy distribution of the laser light emitted from the probe can be determined to some extent by selecting the shape of the probe according to the purpose, but the laser light is incident only on a certain region and It is not possible to control it without making it enter the area. Therefore, the laser beam is also applied to areas other than the target area, which may damage the tissue in that area.

[0007] Further, when the affected area to be treated is inside the tissue, it damages normal tissue from the tissue surface to the affected area. Therefore, after incising the tissue up to the affected area, the affected area is treated. However, it is necessary to directly irradiate the laser beam, which causes delay in recovery or healing of the patient.

[0008] Therefore, an object of the present invention is to cause the transformation of the tissue only in the treatment target region as much as possible and reduce the damage to other tissue sites.

Another object is to reduce the damage to healthy tissue even if the laser beam is irradiated from the surface of the tissue when the affected area is inside the tissue.

[0010]

A laser beam irradiation system according to the present invention, which has solved the above-mentioned problems, is a target targeting a site where a substance that generates laser light by absorbing laser light is present on the surface of or inside a living tissue. And a laser light irradiation means for generating heat by irradiating the target with laser light.

Further, the laser beam irradiating means is provided in a laser beam emitting part for receiving the laser beam from the laser beam generator and emitting the laser beam, and at least in the emitting direction of the laser beam from the emitting part. A unit provided with a cooling unit and a cooling medium supply means for circulating a cooling medium in the cooling unit is preferably used.

In this case, it is preferable to use pulsed laser light as the laser light.

Further, it is preferable that a tissue temperature detecting means is provided in the laser beam irradiation region, and more preferably, the target contains sugar-containing iron oxide.

[0014]

According to the present invention, a target is a site where a substance that absorbs laser light and generates heat is present on the surface of a living tissue such as the surface of skin or inside the living body such as the prostate. Examples of substances that generate heat by absorbing this laser light (hereinafter also referred to as exothermic substances) are carbon powder, dyes, pigments, manganese dioxide, and red iron oxide (iron oxide;
Fe ₂ O ₃ ), iron oxide (Fe ₃ O ₄ ) and other inorganic powders,
Alternatively, an organic powder or the like can be used.

This exothermic substance can be applied to the target site as it is, but water (particularly physiological saline is preferable), alcohol, glucose solution and the like are dispersed as a dispersion medium so as not to scatter, and the heat resistance is high. It is preferably dispersed in the molecule. If necessary, binder in the dispersion,
The viscosity can be adjusted by adding a thickener or the like. Furthermore, the exothermic substance is the type of laser light used,
In particular, the wavelength can be selected. In the case of Nd: YAG laser light, since it is easily absorbed by the protein, it is possible to make the protein a pyrogen by injecting the protein substance from the outside.

The dispersion can be applied to the surface of living tissue, but can be injected into the inside of the tissue through an injection needle or the like punctured from the surface of the tissue. When injecting into a tissue, a pyrogen and a dispersion liquid are selected in consideration of the safety of the living body. From this viewpoint, carbon, manganese dioxide, iron oxide, and melanin pigment are suitable as the exothermic substance. Water and alcohol are preferred as the dispersion medium. As a specific example of the case of using iron oxide, "Fezin" manufactured by Yoshitomi Pharmaceutical Co., which is used for intravenous injection in patients with iron deficiency anemia, can be mentioned. This "fegin" is a monosaccharide iron oxide (Ferric
Oxide, and is called a composition _{[Fe (OH) 3] m} [F 22 H 22 O 11] n).

When a portion where an exothermic substance is present is targeted and irradiated with laser light, the exothermic substance absorbs the laser light and generates heat. As a result, degeneration of the tissue occurs, and the tissue coagulates or evaporates.

On the other hand, when the exothermic substance is not present, a large amount of laser light energy is required to vaporize or coagulate the tissue at a certain site. Therefore, damage is also given to parts other than that part.

This point will be briefly described with reference to FIG. 1. When irradiating the surface of the target tissue M with the laser light L from the optical fiber 1, as shown by the chain double-dashed line, the part where no exothermic substance is present is present. When irradiation is performed with the power P ₀ of the corresponding laser light, the temperature distribution TD ₀ in the depth direction of the tissue M draws a gentle curve and decreases in temperature as illustrated. On the other hand, when the layer 2 containing the heat-generating substance is formed on the surface of the target tissue M in advance, the laser light L
The target tissue M
The temperature at the surface portion of the is locally increased. Therefore, the power P ₁ of the laser light for obtaining the desired temperature on the surface portion of the target tissue M is lower than the power P ₀ described above. Moreover, in the temperature distribution TD ₁ in the depth direction of the tissue M, the energy of the laser light is consumed (absorbed) in the surface portion of the target tissue M as shown in the figure, so that when the depth is deeper than that, the temperature drops sharply. . As a result, for example, in the treatment of cutaneous bruises and the treatment of skin cancer, it is possible to necrotize only the bruises and cancer tissue parts and not to damage the part deeper than the bruises and cancer tissues.

When irradiating the inside of the tissue M with laser light, it is desirable to irradiate the laser light while cooling the surface of the tissue, as shown in FIG. That is, the target zone 20 is prepared by previously injecting a dispersion liquid containing a heat-generating substance into a predetermined site in the tissue M with an injection needle or the like.

On the other hand, as a laser beam irradiation device, the guide window 1 is formed at the tip of the cylindrical holder 10 by using a transparent ceramics or plastic capable of transmitting the laser beam.
2 is provided, and an optical fiber 1 is provided at the center of the holder 10.
And a cooling medium, for example, a supply conduit 14 and a drain conduit 16 for the water W are opened in a flow chamber 18 surrounded by the guide window 12 and a partition wall 10A at the tip of the holder 10 to supply the water W. Distribution room 18 through 14
A device adapted to be supplied inside and drained from the drainage conduit 16 is used. The laser light L is applied to the target zone 20 in the process of continuously or intermittently circulating the water W in the circulation chamber 18 using this laser light irradiation device.

In this case, the energy E temperature distribution of the laser light in the depth direction of the tissue M is lowered from the surface of the tissue M in a gentle curve as shown in the figure, while the temperature distribution TD ₂ Indicates that the surface portion of the tissue M is forcibly cooled by the water W passing through the flow chamber 18 and becomes lower than that in the case where it is not cooled, and in the region where the cooling heat is not transmitted, the temperature is the temperature corresponding to the incident energy amount. Become. Since it gets deeper and heat is generated in the target zone 20,
A sharp temperature rise is shown, and in the deeper portion, the energy of the laser light is consumed (absorbed) in the target zone 20, so that the temperature sharply drops.

Therefore, as a whole, the target zone 20 is intensively heated to cause evaporation and coagulation of the tissue in that portion. Further, as is clear from the temperature distribution TD ₂ , the temperature from the tissue surface to the target zone 20 is low, and damage to the tissue in that portion is prevented.

[0024]

EXAMPLE A first concrete example of cooling the tissue surface portion of the present invention will be described with reference to FIGS. 3 and 4. In this example, the tip of the irradiation device is inserted into a body cavity such as the esophagus, stomach, or large intestine, and a target 20 such as a tissue that is lateral to the emitting direction of the optical fiber 1 is received.
Laser light is radiated to cause necrosis.

The optical fiber 1 is a laser beam generator 22.
Is optically coupled to. A protective tube 24 such as a plastic tube is provided around the optical fiber 1.

Reference numeral 26 is a reflector, which is made of, for example, heat resistant ceramics such as heat resistant glass, artificial sapphire, or aluminum. A metal such as stainless steel may be used. The reflector 26 has an opening 28 on its side. A through hole 26a is formed so as to communicate with the opening 28. A connector 30 is fixed to the through hole 26a, for example, via a screw portion, and the connector 30 holds the tip of the optical fiber 1. The opening 28 of the reflector 26 is opened at an opening angle of about 60 degrees in a vertical cross section, and a gold plating layer 32 is formed on the front surface thereof.

On the other hand, a cover body 34 made of translucent ceramics, such as heat-resistant glass, is connected to the tip of the protective tube 24 via a metal connecting tool 30 and surrounds the reflector 26. At the tip of the cover body 34, the outflow port 34a
Are formed. A fluid, for example, cooling water W is supplied between the protective tube 24 and the optical fiber 1. One or a plurality of through holes 30a are formed in the collar portion of the connecting tool 30.

The laser light from the laser light generator 22 is
The light is emitted from the tip through the optical fiber 1, collides with the gold-plated layer 32, is reflected by the gold-plated layer 32, passes through the opening 28, passes through the cover body 34, and reaches the target 20 in the tissue M. Is irradiated.

During this irradiation process, the cooling water W is continuously supplied into the protective pipe 24. The cooling water W passes through each through hole 30a of the connector 30, passes between the reflector 26 and the cover body 34, and continuously flows out from the outflow port 34a. As a result, when the laser light irradiation device of the present invention is inserted into the body cavity, mucus does not enter the cover body 34. Even when it is inserted into the stomach, gastric juice does not enter. Therefore, the inside of the cover 34 is always kept clean.

On the other hand, when the cooling water W is supplied, the opening 2
8 and the inside of the through hole 26a are always filled with the cooling water W, so that the portion of the tip end of the optical fiber 1 facing the inside of the through hole 26a, the reflecting surface, and the gold plating layer 32 in the embodiment are cooled, and these parts are cooled. However, even if the power of the laser light is increased, it will not be damaged by the heat of the laser light.

FIG. 5 shows a second embodiment, in which the protective tube 24 and the cover body 26 are connected by a sleeve-shaped connecting member 30B, and the reflector 26 and the optical fiber 1 are connected by the connecting member 30.
While connecting by A, through hole 30b in the connecting tool 30A
And a conduit 36 made of a plastic tube or the like is connected to communicate with the through hole 30b.

Also in this second mode, the cooling water W is continuously supplied into the conduit 36 during the laser light irradiation process. The cooling water W passes through the through hole 30b of the connector 30A,
After passing through the through hole 26a, through the opening 28, between the reflector 26 and the cover body 34, and finally through the light transmitting 30c of the connector 30A, through the gap between the conduit 36 and the protective tube 24. Drained to the outside. Therefore, in the first mode, the cooling water W is one-way, whereas in the second mode
In the above mode, the return system is adopted.

Also in the second mode, since the cooling water W is constantly circulated in the through hole 26a and the opening 28, the portion of the tip end of the optical fiber 1 which faces the through hole 26a and the reflector 26 are provided. Damage due to the heat of the laser light is prevented.

FIG. 6 shows an example in which the reflecting surface of the reflector 26 is a concave surface 32A. In the case of this concave surface, the laser light energy is concentrated at the point P in the figure,
The target 20 can be intensively heated even with a low laser light power.

As the reflecting surface of the reflector, a thin mirror can be fixed by adhesion with an adhesive or the like. When the reflector is made of stainless steel or the like, it can be used as it is if the reflecting surface is mirror-finished.

In the above-mentioned example, the cooling water is used for cooling, but a gas such as air or nitrogen may be used. Laser light does not directly project from the tip of the optical fiber to the reflecting surface,
It is also possible to project at the tip of the optical fiber through a medium that transmits laser light.

According to such a circulation system of the cooling medium, it is possible to prevent the invasion of the body fluid and the foreign matter of the tissue, and to cool the emitting end portion and the reflecting surface portion of the optical fiber, thereby protecting them from the heat of the laser beam.

The method of irradiating a laser beam in the process of circulating the cooling medium of the present invention can be applied to the treatment of the prostate using a balloon catheter, for example.

FIG. 7 shows an outline of a balloon catheter device, which is an insertion tube 4 made of, for example, a polyethylene tube which is relatively flexible but has a certain degree of rigidity.
A holding tube 42 made of, for example, a polyethylene tube is concentrically provided at the center of 0, and a metallic leading member 44 is attached to the tip of the holding tube 42. Between the rear part of the head member 44 and the front part of the insertion tube 40,
A balloon 46, which is made of flexible rubber latex or plastic and is transparent to laser light, is fixed. This balloon 46 is supplied from the cooling water tank 48 to the water pump 5
By setting the difference between the amount of water supplied by 0 and the amount of return water to the cooling water tank 48, the tissue M is swollen and brought into close contact with the tissue M.

The optical fiber 1 is inserted into the holding tube 42 and fixed to the inner surface of the holding tube 42 via the holder 52. The holding tube 42 is selected from a material capable of transmitting laser light. Therefore, the laser light is emitted to the periphery through the holding tube 42. Although a part of the laser light goes straight forward, it has reflectivity because a gold plating layer or the like is formed on the rear end surface of the convex portion 44a of the leading member 44, and therefore the laser light is convex. The light is reflected at the rear end surface of the portion 44a. The reflected laser light eventually passes through the holding tube 42 and enters the balloon 46, and the balloon 4
It is incident on the inside of the tissue M through 6.

As shown in the drawing, the core portion is exposed at the tip of the optical fiber 1 so that the laser light is diffused and emitted from the tip of the optical fiber 1, and a light-scattering powder is applied to the outer surface of the exposed core portion 1a. It is desirable to adopt a means such as forming a scattering layer having a body or processing unevenness.

A thermocouple 54 is fixed to the inner surface of the balloon 46 by adhesion or the like, and its lead wire 56 is led out to the outside and connected to a temperature controller 58.

In this laser light irradiation device, the cooling water W is supplied between the insertion pipe 40 and the holding pipe 42 by the water feed pump 50 while being inserted into the tissue M.
The balloon 46 is inflated. A part of the cooling water W enters the inside through the through hole 42 a of the holding pipe 42 and returns to the cooling water tank 48 through the cutout portion of the holder 52. As a result, the vicinity of the inner wall surface of the tissue M is cooled.

In the process of circulating the cooling water, the laser light from the laser light generator 22 is emitted from the core exposed portion 1a at the tip of the optical fiber 1. The emitted laser light enters the tissue M through the protective tube 42 and the balloon 46, and laser irradiation treatment is performed on the portion including the target 20.

The surface temperature of the tissue M is detected by the thermocouple 54, and the circulating amount of the cooling water is controlled by the water supply pump 50 so that the tissue temperature does not become excessive, or by the cooling water temperature controller (not shown). It is controlled by controlling the temperature.

FIG. 8 shows how the system of FIG. 7 can be used to treat the prostate. The balloon catheter is inserted through the urethra 60 to the bladder 62. In the illustrated balloon catheter, a small balloon 46A is provided at the tip of the balloon 46 to form a two-stage balloon.
The small balloon 46A portion is inserted beyond the neck portion 62A of the bladder 62, and the balloon catheter is expanded during operation so that the balloon catheter can be moved to the neck portion 6A.
2A is caught in the urethra so that it does not get out.

In this balloon catheter, as shown in FIG. 7, the prostate 46 is irradiated with laser light in the process in which the balloon 46 is expanded and cooling water is circulated therein.

When irradiating the prostate 64 with laser light, irradiating only the inside of the prostate 64 as the target 20 and maintaining the temperature of the inner wall portion of the urethra 60 at a low temperature accelerates postoperative healing. Therefore, it is effective to irradiate the laser light while circulating cooling water in the balloon 46 and cooling the vicinity of the inner wall surface of the urethra and the sphincter muscle portion 63.

Prior to the operation, a pyrogen is injected into the prostate by direct injection or intravenous injection. Since the laser light is irradiated to the target 20 into which the exothermic substance is injected, the temperature of the target 20 is particularly high, and the protein inside the prostate is coagulated, and the postoperative healing is achieved.

In the process of irradiating the laser beam, excessive irradiation of the laser beam may damage the prostate and the rectum 66. Therefore, the rectum catheter 68 is inserted into the rectum 66, and the rectal catheter 70 is operated by the temperature sensor section 70. It is desirable to control the emission energy of the laser light while detecting the temperature of the inner wall surface of 66. Reference numeral 72 denotes a pressing balloon, which bulges from the insertion portion 74 and is brought into close contact with the inner wall surface of the rectum 66 by the temperature sensor portion 70, thereby improving the temperature detection accuracy.

In the present invention, there are both a case where the laser light is focused only on the surface of the tissue and a case where the laser light is focused only on the inside of the tissue. In any case, it is desirable that the laser beam is not a continuous wave but a pulsed one, especially when the tissue surface is irradiated with the laser beam. As the means for giving the pulsed laser light, the conventional means can be adopted as it is.

[0052]

As is apparent from the above description, according to the present invention, it is possible to cause the transformation of the tissue only in the treatment target site and reduce the damage to other tissue sites as much as possible. In the case where the affected part is inside the tissue, even if the laser light is irradiated from the surface of the tissue, it is possible to reduce the damage to the healthy tissue.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a laser light irradiation mode of the present invention and a temperature distribution in a tissue depth direction.

FIG. 2 is an explanatory diagram showing a laser light irradiation mode of the present invention by a cooling water circulation system and a temperature distribution in a tissue depth direction.

FIG. 3 is a vertical cross-sectional view of a lateral laser light irradiation system.

FIG. 4 is a perspective view of the reflector.

FIG. 5 is a vertical cross-sectional view of another lateral irradiation system of laser light.

FIG. 6 is a vertical sectional view showing an example of another reflector.

FIG. 7 is a schematic vertical sectional view of a balloon catheter system.

FIG. 8 is a cross-sectional view of an example in which a balloon catheter system is applied to prostate treatment.

[Explanation of symbols]

1 ... Optical fiber, 20 ... Target zone, 22 ... Laser beam generator, M ... Living tissue, L ... Laser beam, W ... Cooling water.

Claims (5)

[Claims] 1. A target means for targeting a site where a substance that generates laser light by absorbing laser light is present on the surface of or inside a living tissue, and a laser for generating heat by irradiating the target with laser light. A laser light irradiation system for a living body, comprising: a light irradiation means. 2. A laser beam emitting section for emitting the laser beam when the laser beam irradiating means receives the laser beam from the laser beam generator, and a cooling provided at least in the emitting direction of the laser beam from the emitting section. The laser light irradiation system for a living body according to claim 1, further comprising: a cooling unit and a cooling medium supply unit that causes a cooling medium to flow through the cooling unit. 3. The laser light is pulsed laser light.
Alternatively, the living body laser irradiation system according to claim 2. 4. A tissue temperature detecting means is provided in a laser light irradiation region, claim 2, or claim 3.
The system for irradiating a living body with a laser beam as described above. 5. The laser irradiation system for a living body according to claim 1, wherein the target contains sugar-containing iron oxide.