Ex-Vivo Exposure on Biological Tissues in the 2-μm Spectral Range with an All-Fiber Continuous-Wave Holmium Laser

Abstract

We present the results on the interaction of an all-fiber Holmium-doped laser CW radiation at a wavelength of 2100 nm with soft tissues and compare it with the other results obtained by the most used solid-state laser systems. Ex-vivo single spot experiments were carried out on the porcine longissimus muscles by varying the laser impact parameters in a wide range (average output power 0.3, 0.5 and 1.1 W; exposure time 5, 30 and 60 s). Evaluation of the laser radiation exposure was carried out by the size of coagulation and ablation zones on the morphological study. Exposure to a power of 0.3 W (1.5–18 J of applied energy) caused only reversible changes in the tissues. The highest applied energy of 66 J for 1.1 W and a 60-s exposure resulted in a maximum ablation depth of approximately 1.2 mm, with an ablation efficiency of 35%. We have shown that it is not necessary to use high powers of CW radiation, such as 5–10 W in the solid-state systems to provide the destructive effects. Similar results can be achieved at lower powers using the simple all-fiber Holmium laser based on the standard single-mode fiber, which could provide higher power densities and be more convenient to manufacture and use. The obtained results may be valuable as an additional experimental point in the field of existing results, which in the future will allow one to create a simple optimal laser system for medical purposes.

Ex Vivo Exposure to Soft Biological Tissues by the 2-μm All-Fiber Ultrafast Holmium Laser System

“…The results obtained from ex vivo experiments with tissues of postmortem animals are part of a major study of the effect on biological tissues of two-micron laser radiation. The next stage will be in vivo experiments on animals using the laser systems studied in this work and the previous one [41].…”

“…In this paper, we present the results of ex vivo exposure on soft tissues while using an ultrafast all-fiber Ho-doped laser system and compare them with the results obtained earlier in [41] with a CW Ho-doped fiber laser under the same conditions and applied energy. A simple, unique Ho-doped laser system generated ultrashort pulsed radiation with less than 1 ps pulse width, with a repetition rate of 20 MHz at a central wavelength of 2.06 µm.…”

“…Additionally, we carried out a comparison of pulsed and continuous-wave 2-µm radiation effects on the same soft biological tissues. Ex vivo investigation of CW Ho-doped fiber laser radiation exposure in a wide range of applied energy (1.5-66 J) at a wavelength of 2.1 µm on longissimus porcine muscle tissues was presented in our previous work [41], which also contains a detailed description of the CW Ho-doped fiber laser scheme, as well as the setup used in the experiment.…”

“…Sci. 2022, 12, 3825 5 of 13 fiber laser radiation exposure in a wide range of applied energy (1.5-66 J) at a wavelength of 2.1 μm on longissimus porcine muscle tissues was presented in our previous work [41], which also contains a detailed description of the CW Ho-doped fiber laser scheme, as well as the setup used in the experiment.…”

Исследование Морфофункциональных Изменений Биотканей После Воздействия Двухмикронного Лазерного Излучения

“…В качестве источника лазерного излучения использовался полностью волоконный гольмиевый лазер, работающий в непрерывном режиме на длине волны 2100 нм и максимальной выходной мощностью 2 Вт. Подробное описание лазерной схемы, параметров излучения, а также принципиальная схема экспериментальной установки по воздействию лазерного излучения на биоткани представлены в работе [3]. Исследования проводились на нескольких десятках белых репродуктивных мышей-самцов массой от 23 до 30 г. На кожные ткани мышей наносили прямую лазерную рану.…”