A.E. Shupenev1, V.M. Ryzhakov2, A.R. Aleksandrov3, I.A. Kudashov4, A.G. Grigoryants5

1–5 Bauman Moscow State Technical University (Moscow, Russia)
1 ash@bmstu.ru, 2 vallav033@gmail.com, 3 aleksandrey99@gmail.com,
4 kudashov@bmstu.ru, 5 grigoryants@bmstu.ru

Urolithiasis is a common urological disease affecting millions of people worldwide. It is characterized by the formation of hard, crystalline deposits (stones) in the urinary system, which can lead to problems with metabolic processes in this system. According to statistical data, approximately 10–15% of the world's population encounters the presence of a kidney stone at some point in their lives, and the recurrence rate can reach 10–23% within 1 year, 50% within 5–10 years, and 75% within 20 years after the manifestation of the disease. Currently, laser lithotripsy is the main surgical treatment for urolithiasis. This procedure uses lasers to break up stones in the urinary tract, but there are still some challenges with it.

For example, there can be problems with thermal effects on surrounding tissues and with the fragmentation of stones. Also, laser retropulsion (the movement of stone fragments back into the kidney) can occur. In this regard, one promising direction for the development of laser lithotripsy is the use of ultrashort pulse lasers operating with high energy and short pulse durations. As part of the conducted research, a series of experiments on the interaction of femtosecond laser radiation with phantoms of renal concretions in air were performed. As a result of varying three parameters of laser radiation (radiation power (W), radiation frequency (kHz), and number of passes), the efficiency of laser treatment was evaluated. The main indicator of destruction efficiency was the total change in the mass of the phantom of the kidney stone, as well as the value of mass loss per unit energy (joule), which is important for optimizing the lithotripsy process.

It was shown that the most optimal process of phantom masses removal was achieved by radiation of average power of 10 W at a frequency of 30 kHz and 10 passes, at which the removal efficiency was 3.167 μg per unit of energy. In this way, the experimental results obtained allowed us to determine the optimal parameters of laser radiation for effective ablation of kidney stones. These results will be useful when setting the technical requirements and specifications for the laser lithotripter at the stage of its development.

Shupenev A.E., Ryzhakov V.M., Aleksandrov A.R., Kudashov I.A., Grigoryants A.G. Investigation of femtosecond laser irradiation efficiency on phantom stone for laser lithotripsy tasks. Biomedicine Radioengineering. 2024. V. 27. № 6. P. 92–102. DOI: https:// doi.org/10.18127/j15604136-202406-09 (In Russian)

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