CC BY
4*
ALT'23 The 30th International Conference on Advanced Laser Technologies
B-I-9
Physical features of laser multiwave action on biological tissues
Andrei V. Belikov1'2, Yulia V. Fedorova1, Sergey N. Smirnov1, Anastasia D. Kozlova1, Viktor Yu. Chuchin3
1-ITMO University, 49 Kronverksky Pr., 197101, Saint Petersburg, Russia 2- Pavlov First St. Petersburg State Medical University, 6-8 L'va Tolstogo str., 197022, Saint Petersburg, Russia 3- Limited Liability Company «NPP VOLO», 4-617th line of V. Island, 199034, Saint Petersburg, Russia
Main author email address: [email protected]
The progress of laser medicine is associated not only with the development and implementation of new laser sources, but also with the search for new modes of operation of already known lasers. In this regard, it is very promising to use several wavelengths to action on biological tissues. For example, in neurosurgery, a dual-wavelength surgery system to resect brain tumors is very promising, where a continuous wave (CW) thulium (1.94 ^m) laser applied before/during/after ^s-pulsed Er:YAG ablation to maintain a blood free zone while retaining the high efficiency of Er:YAG ablation [1]. In dermatology, when vein sclerosis is used, the multiwave effect of pulsed dye and Nd:YAG lasers is used, in which the effect of dye laser radiation (0.585 ^m) leads to an increase in the absorption of Nd:YAG laser radiation (1.064 ^m) by the dermis, as a result of which the efficiency of destruction of veins by radiation of this laser increases [2]. In laser drug delivery, multiwave laser action can also be used, in which one wavelength, for example, an Er:YLF laser (2.81 ^m) is used for biotissue microporation and drug delivery, and the other (0.656±10 ^m) for photodynamic effect on the drug [3].
In this study, the problems of optical and thermophysical modeling of multiwave laser action in dermatology with laser treatment of blood vessels and in neurosurgery with laser interstitial therapy of malignant tumors will be touched upon. We will also represent experimental results of photodynamic treatment of fungus Candida Albicans by radiation of different visible wavelength.
Numerical optical and thermophysical models of human skin with and without telangiectasia have been developed. The possibility of using laser radiation with one wavelength to heat the skin with telangiectasia in order to convert hemoglobin in the blood of the vessel into methemoglobin and thereby control the optical properties of the skin, followed by exposure of the vessel to laser radiation with a second wavelength in order to coagulate it, is considered. The effect of methemoglobin concentration on the extinction coefficient and the degree of optical clearing of the skin was studied by numerical methods. It has been established that methemoglobin in the composition of the skin leads to its greatest optical clearing at wavelengths near 0.441 ^m and 0.578 ^m and maximizes the extinction coefficient at wavelengths near 0.629 ^m and 1.105 ^m. It has been demonstrated that the replacement of hemoglobin with methemoglobin leads to a change in the absorbed optical power in the skin layers, which can be used to control the optical properties of the skin when creating laser systems and technologies for the treatment of skin diseases, including laser sclerosis of telangiectasias.
Numerical optical and thermophysical models of a human brain tumor have been developed. The features of the effect of laser radiation with a wavelength of 0.98 ^m and 1.56 ^m on brain tumor (glioma) tissues are considered. It has been demonstrated that the combined effect of multiwave action on a brain tumor makes it possible to increase the efficiency of laser coagulation of the tumor.
In an experiment on a daily culture of the fungus Candida Albicans, the antimycotic activity of chlorine-containing photosensitizing drugs "Chloderm" and "Chloderm with hyaluronic acid" (Russia) was evaluated when exposed to radiation with wavelengths of 0.405, 0.450 and 0.656±10 ^m. The high antimycotic activity of the studied drugs was demonstrated. The main mechanisms of the effect of radiation with the investigated wavelengths on the biotissues are discussed.
The research was supported by Russian Science Foundation (project No. 22-25-00468).
[1] N. Katta et al. Laser brain cancer surgery in a xenograft model guided by optical coherence tomography, Theranostics, vol. 9, No. 12, pp. 3555— 3564, (2019).
[2] Trelles M. A. et al. Treatment of leg veins with combined pulsed dye and Nd: YAG lasers: 60 patients assessed at 6 months, Lasers in surgery and medicine, Vol. 42. - №. 9. - pp. 769-774, (2010).
[3] A. V. Belikov, S. N. Smirnov and A. D. Tavalinskaya, Laser Delivery and Spectral Study of a Chlorine-Containing Drug for the Treatment of Onychomycosis at Sequential Laser (X= 2810 nm) and Photodynamic (X= 656±10 nm) Impact, Optics and Spectroscopy, pp.1-9, (2021).
