High-Intensity Focused Ultrasound: Heating and Destruction of Biological Tissue
- PDF / 1,622,190 Bytes
- 12 Pages / 612 x 792 pts (letter) Page_size
- 94 Downloads / 183 Views
NIQUE OF MEDICAL MONITORING AND VISUALIZATION
High-Intensity Focused Ultrasound: Heating and Destruction of Biological Tissue T. A. Andreevaa, A. E. Berkovicha, N. Y. Bykova,*,**, S. V. Kozyreva, and A. Ya. Lukina aPeter
the Great St. Petersburg Polytechnic University, St. Petersburg, 195251 Russia *e-mail: [email protected] **e-mail: [email protected]
Received February 17, 2020; revised February 17, 2020; accepted February 17, 2020
Abstract—The results of a numerical study of heating and destruction of a biological tissue under the action of a series of focused ultrasound pulses generated by a multielement array (tumor treatment programs) are presented. Irradiation programs are considered that differ in the locations of focal points within a tissue (the Archimedean and “square” spirals), the number of pulses in the series, and the time delay between pulses. A significant influence of the parameters of the pulse series and perfusion process on the size of the thermal lesion area in a tissue was established in a considered range of moderate intensities of radiation. It was shown that the heat propagation process in the tissue turns with time to a quasi-spherical pattern and is weakly dependent on the irradiation program type. This characteristic of the process is discussed in terms of its possible use to optimize protocols of medical procedures utilizing focused ultrasound. DOI: 10.1134/S1063784220090030
INTRODUCTION In the last decade, along with conventional surgical methods of oncotomy, high-tech treatment techniques have become more widely used, such as highintensity focused ultrasound (HIFU) [1–5]. The HIFU technique is a challenging noninvasive means for the treatment of breast, prostate, thyroid, liver, and kidney cancer. It consists in the effect of a series of ultrasonic pulses on a biological tissue resulting in tumor necrosis. The HIFU procedure requires planning of parameters of separate pulses in the series (a radiation intensity and pulse duration), setting the time sequence of pulse emission and the spatial location of focal points of separate pulses within a tissue. An adequate choice of parameters determines the quality of treatment, which should result in necrosis of the entire tumor volume. Temperature monitoring in the HIFU process is important to minimize both possible damage to a healthy tissue and harmful effects like tumor rupture with subsequent metastasis through blood perfusion. This work aims at a theoretical study of the impact of pulses of focused ultrasound on a given volume of a biological tissue with properties typical for breast fat tissues. In a general case, the simulation of the HIFU procedure implies a mathematical description of consistent processes of propagation of ultrasonic waves in the tissue and its heating and, under certain conditions, together with related processes (cavitation, chemical transformations). As a rule, the problem on
propagation of ultrasound in a medium and the problem on the calculation of the thermal field together with determination of the ar
Data Loading...
