Abstract
BACKGROUND: High-Intensity Focused Ultrasound (HIFU) represents a non-invasive treatment approach that utilizes non-ionizing radiation. This technique has found clinical utility in managing both benign and malignant solid tumors. OBJECTIVE: This study aimed to investigate the variations in HIFU frequency and duty cycle influence thermal lesion formation in tissue to identify the optimal parameter combination for HIFU therapy in multi-layered tissues. MATERIAL AND METHODS: In this theoretical framework, a model of HIFU application to multi-layer biological tissues was created. Four unique HIFU parameter sets, defined by combining high or low frequency with high or low duty cycle, were comprehensively examined. The study analyzed how these settings influenced temperature distributions and lesion area in the layered tissue to ascertain the ideal combination of frequency and duty cycle parameters. RESULTS: Simulation results revealed that the former parameter set (high frequency, low duty cycle) was optimal for treating smaller, superficial tumours, whereas the latter combination (low frequency, high duty cycle) proved effective for deeper-seated lesions. Regarding thermal dose metrics, the high-energy setting (high frequency, high duty cycle) generated the most extensive lesion area and highest peak temperature, in contrast to the low-energy configuration (low frequency, low duty cycle), which produced the smallest coagulation zone and lowest focal temperature. CONCLUSION: The study demonstrates that optimal HIFU therapeutic outcomes require frequency-duty cycle combinations tailored to tumour characteristics, with high-frequency/low-duty cycle for shallow small tumours and low-frequency/high-duty cycle for deep lesions, providing a framework for precision parameter selection in clinical applications.