Processes of heating and destruction of the breast fat tissue under the action of focused high-intensity ultrasound generated by a 128-element transducer are considered. The simulation of a thermal problem is carried out by anumerical solution of the heat transfer equation. The acoustic pressure field in the tissue is calculated using the Rayleigh integral. A system of dimensionless scaling parameters is proposed to describe the non-stationary process of heat propagation. The influenceof the space localization of foci in a series of pulses on the lesion size is analyzed. The results demonstrate the advantages of a tissue processing program withspatially divergingfocal points of pulses, consisting in a more uniform heating of the tissue and the formation of a continuous ablation area. The impact of the perfusion process on the lesion size is considered.