FI90629B - Laser device - Google Patents

Description

1 90629

LASER DEVICE - LASER ORDERING

The invention relates to a laser device for photodynamic therapy, which device comprises a laser source 5 for generating a laser beam of a certain wavelength and laser beam guide means for directing the laser beam to tissues to which a dye absorbing the same wavelength has been transferred.

Certain dyes which absorb different wavelengths of light, which can be injected into the human body as a solution, for example, can be utilized in so-called photodynamic therapy for the treatment of cancer or viral therapies using relatively low doses of laser radiation. In this case, the subject to be treated, such as e.g. 15 cancerous tissues or viruses, is selectively destroyed by exposing them to a laser beam or several beams which are guided to the subject either directly or by means of an optical light guide, fiber or fibers and the like. Since certain types of tissues, such as e.g. cancerous tissue, collect certain dyes to be used, considerably more than other surrounding tissue, laser light having a wavelength corresponding to this dye is also absorbed much more efficiently. to "stained" tissue. In this way, the laser beam 25 can be used to destroy the desired cells, viruses, etc. while remaining intact with other surrounding cells.

Photodynamic therapy has become known mainly due to the treatment of so-called hematoporphyrin and dye laser (rhodamine 30 6G). When hematoporphyrin is injected into the blood of a patient to be treated, e.g., about 25 mg per kilogram of patient weight, the next day, using a red laser beam (630 nm), can dye the tissue saturated with dye without damaging the healthy tissue. In this case, the red laser beam breaks down hematoporphyrin into free oxygen radicals, which effectively destroy, for example, cancerous tissue.

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However, the main disadvantage of hematoporphyrin is its slow degradation in those parts of the human body where laser exposure is not performed and cannot be performed due to the potential for tissue damage. This part of 5 is e.g. skin that accumulates significant amounts of hematoporphyrin, which makes the skin vulnerable to burns 1-2 weeks after treatment. During this time, the patient cannot go without danger to the outside light, let alone the sunlight, and in the first days after the treatment, the stay inside 10 must also take place in low light.

Furthermore, in photodynamic therapy at 630 nm, the problem is that the penetration of the laser beam, the penetration into the tissues, is quite weak due to e.g. hemoglobin absorption and scattering. The use of more efficient laser devices is already causing potential damage to tissues.

Furthermore, dyes used in photodynamic therapy tend to spread centrally to some internal organs, such as the liver and kidneys, and optimizing treatment in new tissues may cause difficulties.

The object of the invention is to eliminate the above-mentioned drawbacks, in particular when using new photodynamic dyes in the so-called long red and short infrared range of 700 to 1000 nm, such as novel porphyrin compounds and phthalocyanine compounds.

In particular, it is an object of the invention to provide a laser source by means of which the exposure time 30 of the toner is made substantially shorter than with previously used laser devices.

It is a further object of the invention to provide a laser device which can improve the penetration of a laser beam, penetration into tissues without causing immediate thermal damage to the tissues, e.g. coagulation.

In particular, it is an object of the invention to provide 3,90629 novel laser sources which can be used in a more versatile and selective manner in the treatment of various cells and the like.

With respect to the features characteristic of the invention, reference is made to the claims.

According to the invention, the laser source is a titanium-sapphire laser source (Ti: Al 2 O 3) having a wavelength of 680 to 1100 nm, preferably 720 to 760 nm and / or 800 to 900 nm. In general, the infrared range (650 to 1100 nm) has relatively few la-10 serum wavelengths, or the known lasers used are very weak in power and are not sufficient for the described photodynamic treatment or so-called cassette or blood bag exposure. Laser sources already operating in the wavelength range of 680 to 1100 nm, in particular 800 to 15 900 nm, have not been used in photodynamic therapy.

The titanium-sapphire laser source (Ti: Al 2 O 3) according to the invention is already known as a wavelength-adjustable solid-state or crystal laser; however, it has not previously been used in photodynamic therapy. It can be suitably tuned by a second laser or flash-lamp tuned to operate continuously or pulsed in the range of 680 to 1100 nm, preferably 800 to 900 nm. For example, an argon, argon-krypton alloy gas laser, a frequency duplicated (tk) Nd: YAG laser, or a copper vapor laser can be used for excitation.

The excitation device, which may be part of the laser device according to the invention, may also include means for guiding part of the laser beam formed by the excitation laser source to the object to be treated. Said members may consist, for example, of a semipermeable mirror, a mirror arm or the like, a device known per se from laser technology. In this case, the same excitation laser source can also be used diagnostically, e.g. to fluoresce the dye added to the tissues. The power of the laser source of the tuning laser device can be, for example, in the order of 5-40 watts, the power of the part of the laser beam used diagnostically according to the invention, e.g., 5-10% of the power of the laser source. - Naturally, in connection with the laser device according to the invention, a completely separate laser source can be used for diagnostic purposes, such as to dye the dye added to the tissues.

Thanks to the invention, and in particular when using the wavelength range according to the invention of 680 to 1100 nm, in particular 720 to 760 nm and / or 800 to 900 nm (so-called optical window), the penetration of laser light into tissues is substantially better than before, e.g. several mm up to 8 mm.

When the dyeing time of the dye used in photodynamic therapy is substantially shorter than before with the laser device according to the invention and the wavelength range, this speeds up the treatment, while there are no disadvantages in the treatment, e.g. less dye penetrates the internal organs such as liver and kidneys. In general, dye and therapy can be better targeted to, for example, a cancer cell.

In general, the laser device according to the invention and the wavelength range of aal-20 are better suited for photodynamic therapy, the treatment results are better than before and the treatment is more effective and easier to target to the desired treatment target.

The power density 25 of the laser device according to the invention is of the order of 1 to 500 mw / cm 2, e.g. 5 to 300 mw / cm 2, preferably 10 to 200 mw / cm 2.

The invention will now be described in detail by means of exemplary embodiments with reference to the accompanying drawing, in which Figure 1 schematically shows a laser device according to the invention, Figure 2 schematically shows another laser device according to the invention, Figure 3 schematically shows a third laser device according to the invention.

Figure 1 shows a laser device for photodynamic therapy, which device comprises a laser source 5 90629 1 with a guide member 2, such as an optical fiber, and a closure 5 for directing a laser beam to a therapy object. The wavelength range of the laser source 1 is 680 to 1100 nm, in a specific application 720 to 760 and / or 800 to 900 nm.

5 The laser source is a titanium-sapphire laser source. The device further comprises a special laser device 3, the so-called a pumping laser device, e.g., an argon, argon-krypton, tk Nd-YAG, or Cu vapor laser source. The laser source of the pumping laser source 3 is led to the laser source 1, where it excites a 10 Ti: Al 2 O 3 crystal which emits a laser beam of the desired wavelength. The formation of the laser beam, the possible performance, the operation of the shutter and the guidance to the therapeutic object will not be described in more detail in this context, as it is already known.

The laser device shown in Figure 1 further comprises a dielectric mirror 6 arranged to direct a part, e.g. 5-10% of the laser beam generated by the excitation laser source, through the reflection mirror 7 and further to the fiber and 20 further to the therapy object. Thus, the same laser equipment can be used diagnostically and therapeutically.

Figure 2 shows an apparatus comprising a Ti: Al 2 O 3 laser source 1 of the type described above with excitation laser sources 3, shutters 5 and fibers 2 for guiding a laser beam to a therapy object. The device further comprises a separate diagnostic laser device 10 with shutters 11 and fibers 12 for guiding the diagnostic laser beam to the therapy object.

Figure 3 schematically shows a Ti: Al 2 O 3 30 laser source 1 with shutters 5 and fibers 2 for directing a laser beam to a therapeutic target. In the illustrated embodiment, the laser source is flash-tuned and includes a special flash lamp 15, a conventional rearview mirror 13, and a front mirror 14. The laser source shown is thus a flash-tuned Ti: Al 2 O 3 laser source.

The embodiments are intended only to illustrate the invention without limiting it in any way, and embodiments of the invention may vary within the scope of the inventive idea defined by the appended claims.

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Claims (5)

A laser device for photodynamic therapy, to which a laser source (1) is provided for providing a laser beam with a determined wavelength and laser beam operating means (2), thereby directing the laser beam to tissues transmitted to one of the same path length absorbent dye, characterized in that the laser source is a titanium sapphire laser (Ti: Al 2 O 3), the path length of which is in the range 680 - 1100 nm. 2. Laser device according to claim 1, characterized in that the path length of the laser source (1) is 720 - 760 nm and / or 800 - 900 nm. Laser device according to claim 1 or 2, characterized in that the laser device includes a tuning laser device (3), which is an Ar laser source, Ar-krypton blend laser source, frequency doubled Nd-YAG laser source or Cu-laser. änglaserkälla. 20 Laser device according to any one of claims 1-3, characterized in that the laser source (1) is a flashlight-light-stimulated Ti: A1203 laser source. 5. Laser device according to claim 3, characterized in that the tuning laser device (3) hears means (4) for conducting a portion of the laser beam produced by the tuning laser source to the site to be treated.