Study of the Effect of Laser Radiation Parameters on the Efficiency of Lithotripsy

In this article, we report on experimental studies of the influence of several laser radiation parameters, such as the duration of the laser pulse, the radiation wavelength, and the pulse energy, on the efficiency of the destruction of urinary calculi. The study used a laser lithotripter based on a fiber Tm laser generating at a wavelength of 1940 nm with pulses with a duration of about 1800 & mu;s and pulse energy of up to 6 J, as well as a femtosecond solid-state Yb laser generating at a wavelength of 1032 nm with a pulse duration of about 250 fs and pulse energy of up to 400 & mu;J. A comparative analysis was carried out according to such criteria as the productivity of lasers when removing a unit mass of images and the amount of sample displacement resulting from the retropulsion effect. The results obtained in this work demonstrated that the femtosecond laser loses approximately two times its efficiency in terms of sample material removal. However, this shows the absolute advantage of the photoionization mechanism of femtosecond laser ablation in the study of retropulsion and thermal heating, which were completely absent in this case.