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4The 30th International Conference on Advanced Laser Technologies ALT'23
B-I-10
Experimental substantiation of the prospects for the use of "blue" laser radiation with X= 450 nm for the effective removal of congenital
giant pigmented nevi
Podurar S.A.1, Gorbatova N.Ye.1 , Tertychny A.S.1, Platonova A.D.1, Sirotkin A.A.2' Kuz'min G.P.2 , Tikhonevich O.V.2, Kalachev Yu.L.2, VarevG.A.3
1-Research Institute of Emergency Pediatric Surgery and Traumatology, Moscow, Russia 2- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia 3- Russian Engineering Club LLC, Tula, Russia
Main author email address: [email protected]
Currently, laser methods for the treatment of skin diseases are widely used and actively introduced into clinical practice due to the pronounced selectivity of the effect [1]. Pigmented nevi (PN) are pathological benign skin formations consisting of accumulations of melanocytes, cells containing the pigment melanin. The group of congenital giant pigmented nevi (CGPN) is a special psychological and medical problem associated with extensive damage to the skin and changes in the patient's appearance [2].
The existing numerous methods of treating CGPN are not effective enough or are accompanied by significant damage to tissue structures, and therefore are not always applicable due to the large amount of skin lesions with pigment formation [2].
The purpose of this work is to improve the results of treatment of CGPN by experimentally substantiating the possibility of using laser radiation with a wavelength (^ 450 nm) and developing a method for their effective removal in order to achieve a good clinical and aesthetic result of treatment. As a radiation source, we used a laser device based on the convergence of laser diodes with a total power of up to 10 W, a spot diameter of 0.6 to 1.5 mm, generating continuous and pulsed "blue" laser radiation ^=450 nm.
An in vivo experimental study was performed on the pigmented, black-brown skin of living laboratory rats. The skin was exposed to laser radiation in continuous and pulsed (0.5 sec) modes, with a distance between pulses of 0.5 sec, 0.25 and 0.1 sec, with a constant speed of a single scan of 0.5 cm per 1 second over the surface of the object. We used variable radiation power modes: 3.0 W, 6.0 W, 10.0 W.
During the experiment, visually determined macroscopic changes in the impact zones on the surfaces of these samples were studied, followed by a histological examination immediately after irradiation, as well as on days 4, 12, 30, and 90. Based on the results of an experimental study, a method for removing CGPN was developed based on the selective absorption of laser radiation with a wavelength of 450 nm by pigmented tissues, predominantly containing melanin and hemoglobin, which makes it possible to predict the depth of layer-by-layer removal of pigmented tissues and minimize damage to the underlying tissue structures, including the elements of the skin appendages located there. The optimal modes of "blue" (X= 450 nm) laser radiation for effective removal of CGPN were determined. A preliminary clinical study of the use of this method determined the prospect of its application.
[1] A. A. Sirotkin et al., "Optimization of selective photodestruction by laser radiation of the yellow-green range of capillary angiodysplasia of the
skin," 2018 International Conference Laser Optics (iCLO), St. Petersburg, Russia, 2018, pp. 602-602, doi: 10.1109/L0.2018.8435420 [2] Podurar
S.A., Gorbatova N.E., Zolotov S.A., et al. Pigmented nevi in children, necessity and optimization of their treatment, Russian Journal of Pediatric Surgery. 2023; 27(1, Supplement): p. 142
