JPS63318933A - Medical laser probe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a medical laser probe that performs thermotherapy, coagulation, or hemostasis on human or animal tissue by irradiating the tissue with a laser.

BACKGROUND OF THE INVENTION Significant advances have been made in the field of laser surgery in conjunction with the use of tactile laser probes.

With both contact and non-contact methods, the penetration of laser energy into tissue is limited, and laser treatment of subsurface tissue requires removal or ablation of the overlying surface tissue. This characteristic of laser surgery is not particularly problematic when, for example, the primary purpose of the procedure is to cut through the superficial layers of tissue.

However, there are times when it is desirable to laser irradiate tissue beneath the skin without irreversibly damaging the tissue above it. One such treatment, known as PRT (photoradiation therapy), has been reported to selectively destroy cancerous tissue when the tissue is primed with a photosensitizing agent (T. J. Daugherty, "Malignant "Photoradiotherapy to treat M tumors," Cancer, Res, 38.
:2628-2635.1978).

In PRT, a photosensitizer, and finally a hemotoboruphyrin derivative (HpD), is injected intravenously approximately 48 to 72 hours before the tissue is irradiated with an argon dye laser. It has been found that cancerous tissue is destroyed and normal tissue is largely unaffected.

PRT treatment generally requires irradiating the entire cancer area well below the surface of the tissue. Therefore, it is desirable, if not necessary, to insert the laser probe into the tissue such that the laser beam sufficiently reacts with the photoagonist. Furthermore, in order to irradiate the pre-sensitized cancerous tissue over as wide a range as possible, it is necessary to provide a broad radiation pattern for the tip.

However, known lasers 10-b emit laser energy only from the tip region of the probe as a relatively narrow beam directed qualitatively downward and downward from the probe tip. When this tip is inserted into cancerous tissue, two problems arise. Firstly, because only a relatively small area, e.g. Lighting also requires a lot of time. A second problem is that the high power density of the laser beam can burn tissue in the immediate vicinity of the probe tip. Burns significantly reduce the overall transmittance of the laser beam because it prevents the laser beam from passing through the burned area of tissue.

Besides PRT, the probe, which can spread the laser beam into a wide angle, can be advantageously used for the treatment of gastric cancer, ulcers, gastric or intestinal bleeding or local hyperthermia. A Nd-YAG laser can be used for therapy.

A preferred configuration of the present invention is a quartz, sapphire or diamond conical probe. The design of this probe can be modified to facilitate or inhibit radiation from the sides of the conical probe tip, but the radiation pattern in this case would be similar to that of the probe without the teachings of the present invention. The pattern remains substantially outward along the axis and the illumination area is limited.

Accordingly, the present invention provides a substantially wider angle radiation pattern,
That is, the probe tip according to the present invention for a laser probe with a radial sideways and backward scattering pattern in addition to the normal forward emission not only provides wider-angle tissue irradiation;
Importantly, the probe tip according to the invention, in particular characterized by the possibility of tissue burns, by performing irradiation at a substantially more uniform laser energy density, preferably has a depth of about 1 to 100 μm. It is characterized by an irregular or roughened surface with numerous indentations. As a result, a portion of the laser energy that reaches this surface is reflected and another portion is generally emitted to the adjacent tissue.

A portion of the laser beam thus impinging on this surface from inside the tip is refracted directly towards the tissue, and a portion is further irregularized within the numerous recesses of the irregularly roughened surface. reflected. This scattering of the laser beam occurs across the roughened surface of the probe, so that the emitted laser energy impinges on the tissue from virtually every direction, increasing the radiation field and localizing the tissue. Increases penetration into tissues by reducing severe burns.

The present invention also provides a medical probe adapted to transmit laser energy propagated through a waveguide for application to tissue. The probe includes a laser diffusing portion surrounding a portion of the tip end of the waveguide to cover the laser beam emitted from the tip end of the waveguide, the laser diffusing portion receiving the laser beam. The inner surface is provided with a scratched or roughened surface on the region of the inner surface.

This type of probe is characterized by a scuffed or roughened surface formed on the inner surface of the laser diffusing portion. The laser beam is partially transmitted through the scraped or roughened surface and partially reflected irregularly to reach another part of the probe, where it is Either it is transmitted or it is irregularly reflected again. As a result, laser energy is emitted from the wide outer surface of the probe at a substantially uniform power density. In this case, the laser radiation field is extended, for example over a circular surface of large diameter, so that it can be used in a mode in which it is in contact with the surface of the tissue to coagulate the tissue.

It is therefore an object of the present invention to provide a probe capable of illuminating a large surface area in diffuse illumination mode.

Another object of the present invention is to provide a probe capable of delivering a laser beam from the entire illuminated surface at a substantially uniform power density.

[Embodiment] FIG. 1 is a longitudinal sectional view of a probe 10 according to the present invention attached to the tip or output end portion of an optical fiber 32 of a laser waveguide.

10-Bub 10 is made of a laser transparent material such as a natural or synthetic ceramic material such as sapphire, quartz or diamond. In the illustrated example, the probe 10 includes a conical or tapered laser diffusing portion 12 with a hemispherical portion 12m at the tip end and a main body portion 14. Laser diffusion portion 12 and main body portion 14 are integrally molded with each other, and a flange 16 is formed between body portion 14 and laser diffusion portion 12.

10 - The bulb 10 is fitted into the cylindrical female connector 18 and is integrally attached to the female connector 18 by caulking its mating surfaces or by using a ceramic type adhesive between the mating surfaces. is firmly fixed. Female connector-18
has a female threaded portion 20 on its inner surface that engages with a complementary male threaded portion 30 of the male connector 22. The male connector 18 includes two through holes 24 formed in the cylindrical connector wall to facilitate passage of cooling water W or other fluid. Two through holes 24 (only one shown in FIG. 1) are circumferentially arranged at an angular spacing of 1806.

The male connector 22 is force fit into a flexible tubular jacket 26 made of, for example, Teflon. To achieve this force fit, the male connector 22 is
Male connector 22 has steps 28 at its proximal end and is held firmly within jacket 26 by these steps to prevent detachment of male connector 22 from jacket 26. As mentioned above, the male connector 22 includes a male threaded portion 30 that mates with the female threaded L portion 20 of the female connector 18.

An optical fiber 32 for transmitting the laser beam is inserted into the male connector 22. optical fiber 32
are disposed concentrically within the jacket 26 to form a gap 34 for passage of cooling water or fluid. The optical fiber 32 is tightly fitted to the male connector 22 near the step 28 of the male connector 22, and the step 28 has two slits 28a at 180 They are formed on the circumference at angular intervals of °. A passage 36 for cooling water W is formed between the inner surface of the tip of the male connector 22 and the optical fiber 32.

The assembled tip is then inserted into an endoscope or mounted in other locations as required for the laser beam surgical procedure to be performed.

Optical fiber 32 is optically coupled to a laser generating unit (not shown). The cooling water W is guided to the gap 34, the slit 28a and the passage 36 as necessary,
It is then discharged through the through hole 24 to cool the tissue to be treated.

The laser beam from the laser generating unit is guided through an optical fiber 32 and from its end to the globe 10.
is coupled to the proximal end 38 of. The laser beam then
From the laser diffusing portion 12 of the tip, it is delivered to the tissue M to be treated, as detailed below.

FIG. 2 illustrates the dispersion and dispersion of the laser beam when using the probe according to the invention. As will be described later, the outer surface of the laser diffusing portion 12 of the probe 10 is scraped or roughened to disperse the laser energy over a wide angle, as shown in FIG.

FIG. 6 shows a comparison of the radiant energy densities of a conventional probe tip and a probe tip according to the present invention. Probe tip 11' can be of either type.

Curve 13 represents the density distribution of the laser energy or laser power in a plane perpendicular to the longitudinal axis of the probe tip and spaced below the probe tip. More specifically, the power density is maximum at point 15 (a point along the extended longitudinal axis of the probe tip) and decreases rapidly with increasing distance from this axis. It approximates, albeit very roughly, the laser power density distribution in a cylindrical plane that shares an axis with this probe.This curve 17 basically expresses the radial component of the laser radiation, but This, as will be appreciated, would be very low for a conventional tip since substantially all of the laser energy would be emitted longitudinally downward from the tip 12a'.Therefore, curve 17 would be much lower than the actual It is not intended to indicate the power distribution, but merely to represent the low level of radial radiation.

Curve 19.21 shows the laser power distribution of the probe according to the invention and curve 13.21 of the probe according to the prior art.
17 respectively. As can be seen from curve 19, the peak power density 23 along the central axis of the probe is substantially lower than that of the prior art tip, and, importantly, the power density along the central axis of the probe is substantially lower than that of the prior art tip. It is descending more slowly as a function of distance. This provides relatively uniform laser illumination over a wide area and avoids excessive axial power density that would cause tissue burns. This curve 21 further shows that this radiation is not limited to the region of the tip 12a', but over the entire length of the conical laser diffusing portion 12' of the probe. It is shown that this occurs along the following lines. However, as will be shown in more detail below, the laser power distribution represented by curve 21 is actually achieved by random refraction and scattering of the laser energy inside the probe tip, so that this radiation is distributed along the sides of the tip. Even if the tissue is illuminated by the light, it is not necessarily transmitted radially from this point.

The outer surface of the laser diffusing portion 12 is scraped or roughened to form a non-uniform pseudo-surface generally defined by convex protrusions and concave depressions, as best shown in Figure 3.4. Form random contours. The depth of the surface irregularities or indentations is about 1 to 100 microns, preferably 10 to 60 microns. Scraping or one-sided machining is preferably carried out by a computer-controlled grinding wheel; more particularly, the probe undergoing surface treatment is rotated and then brought into contact with a diamond grinding wheel. The wheel begins at the tip 12a of the probe and traces the untextured portion of the probe back along the conical surface as far as desired. This forms a laser diffusion section 12. The computer controls the feed rate and position of the wheel, as is known. According to a preferred configuration, a grinding wheel with a particle size of 10 to 20 μm is used, and the grinding wheel is moved along the probe at a speed of 3 to 6 mm/sec. As a result, approximately 10μ
- A roughened surface condition defined by the indentations is obtained.

It will be appreciated that by grinding the appropriate diamond particle size, the depth of the indentation may be varied. However, increasing the depth of the indentations, especially above the preferred ranges mentioned above, increases the proportion of laser energy that is reflected inside the probe tip, so that the refracted radially outwardly diffused laser energy is correspondingly less. The tip does not exhibit the desired broad, uniform radiation pattern; another extreme is that increasing the surface roughness beyond the preferred limits described above causes the tissue to become concave indentations when the probe is inserted into the tissue. This prevents the probe from being pulled out.

The operation of the probe according to the invention can be understood by referring to FIG. 4, which shows that the laser beam coupled into the probe from the light guide is internally impinging on the roughened surface 12b of the 10-tape. , will be best understood. The laser energy is a beam of light 31. ．． 33.

Note that these rays do not arrive in a parallel relationship, but instead impinge from various angles, including, in the general case, receiving unexpected internal reflections from irregular surfaces above. This means that each ray follows its own independent optical path.

The incoming light ray is either internally reflected and strikes the surface 12b again, or externally refracted, depending on both its specific intersection with the roughened surface 12b and the angle of incidence; Emitted from the probe to the outside. In the general case, laser energy may be split, ie, some energy is reflected and remaining energy is refracted and emitted. FIG. 4 illustrates several representative optical paths showing complete reflection, complete refraction, and a combination of two modes.

It is important that the laser energy emitted by the probe is not directed in any particular direction, but is emitted in almost all directions. Laser energy is thus delivered radially from the probe and, unlike conventional laser probes, can penetrate tissue in the radial vicinity of the probe tip. In summary, this is a pseudo-random scattering or dispersion of laser energy that results in intense radiation along the probe tip as shown by curve 21 in FIG.

FIG. 7 shows an exemplary embodiment of a probe according to the invention.
As is clear, the dimensions shown are merely exemplary and the dimensions of the probe can be suitably defined according to specific treatment requirements.

For example, the length of the laser diffusion portion 12 of the probe 10 may be appropriately selected according to the insertion depth of the probe into one tissue M, and generally falls within a range of about 1.0 to 7.0 as. Although the tip end of the laser diffusing portion 12 does not necessarily have to be hemispherical, since a pointed end is easily damaged, it is preferable that the tip end of the laser diffusing portion 12 be round.

In the embodiments described above, substantially the entire conical or tapered portion acts to diffuse laser energy therefrom. Alternatively, a limited portion of this conical or tapered section, including the tip end 12m, may act as a laser diffusing section by correspondingly limiting the surface roughness. The flange 16 may be used as a stop for positioning the probe 10 in the tissue M when the probe 10 is advanced into the tissue M until the front end surface of the protruding flange 16 hits the set 1111M as described above. act as a part.

However, the flange 16 may be omitted depending on the case.

FIG. 8 shows yet another embodiment of the present invention. Probe 50 has a substantially U-shaped cross-sectional configuration and includes a receiving portion 52 at the outer periphery of its base for connection to female connector 18 as described above. probe 10
The outer and inner surfaces of the cylindrical portion are hemispherical, and a portion of the cylindrical portion adjacent to the hemispherical inner surface and the hemispherical inner surface are subjected to scraping or roughening to form the laser diffusion portion 54. A rough surface is formed. The rest of the inner and outer surfaces are smooth. An optical fiber 32 is disposed within the receiving portion of the probe 50.

The majority of the laser beam emitted from the end face of the optical fiber 32 enters the laser diffusing portion 54 where it is diffused and then emitted from the outer surface of the tip end portion. The probe can also be used for local hyperthermia, coagulation or photochemical therapy while in contact with tissue without being inserted into the tissue.

[Brief explanation of the drawing]

FIG. 1 is an elevational view showing a part of the 10-branch and its holding member according to the present invention in cross section, and FIG. 2 shows the tissue in the vicinity of the probe shown in FIG. FIG. 3 is an enlarged sectional view of the tip end of the probe, and FIG. 4 is an enlarged sectional view of the surface of the 10-beam. FIG. 5 is an elevational view showing a non-diffusion probe inserted into tissue and illuminating the FFI tissue directly below the probe tip; FIG. Figure a and Figure 7 are for comparing the radiation output density of
FIG. 8 is an elevational cross-sectional view showing an example of the dimensions of a probe according to an embodiment of the present invention; FIG. lO...10-pu12b...Surface (uneven contour) (4 people outside)

Claims (1)

[Scope of Claims] 1) In a medical laser probe that conveys laser energy from the output end of an optical laser waveguide to the tissue to be treated, a laser energy input region formed of a laser-transparent material and receiving the laser from the optical waveguide; and a laser energy emitting surface formed from a laser-transparent material and having an uneven and irregular contour to spread the laser energy incident thereon, so that the laser emission from the probe is spread over a wide range of angles. A medical laser probe characterized by being diffused into. 2) In a medical laser probe that conveys laser energy from the output end of an optical laser waveguide to the tissue to be treated, the laser energy input region formed from a laser-transparent material and receives the laser from the optical waveguide, and the laser transparency a laser emitting surface formed from a material and having an uneven and irregular contour with a plurality of recesses of 1 to 100 μm for diffusing the laser energy incident thereon, thereby diffusing the laser emitted from the probe. A medical laser probe that is characterized by being diffused over a wide range of angles. 3) having a flange from which the laser emitting surface extends, the flange limiting the degree of insertion of the probe into the tissue to be treated;
Medical laser probe as described in section. 4) A patent characterized in that the laser emitting surface has a conical shape, thereby allowing the narrowed area of the cone to be advanced into the tissue and to insert the probe into the tissue being treated. A medical laser probe according to claim 1. 5) In a medical laser probe that carries laser energy from the output end of an optical laser waveguide to the tissue to be treated, a laser energy emitting probe surface formed from a laser-transparent material surrounding the tip end of the optical waveguide and an optical waveguide. a laser energy-receiving probe surface formed from a laser-transparent material surrounding the tip end of the tube and having an uneven and irregular contour, thereby diffusing and scattering laser energy emitted from the probe. A medical laser probe featuring: 6) A medical laser probe that conveys laser energy from the output end of an optical laser waveguide to the tissue to be treated, comprising a laser-transparent material surrounding the tip end of the optical laser waveguide; A hollow inner region is provided between the inner surface of the probe and the inner surface of the probe, which has an uneven and irregular contour, and the laser energy that impinges on the inner surface is unevenly refracted and reflected, so that the laser energy emitted from the probe is A medical laser probe characterized by being diffused and scattered. 7) The medical laser probe according to claim 6, characterized in that the outer surface of the probe is smooth.