Treatment Planning of Scanning Time and Path for Phased High-Intensity Focused Ultrasound Surgery

Cooling time between sequential sonications in the conventional heating method for high-intensity focused ultrasound (HIFU) leads to long treatment time. In order to reduce treatment time, an unequal heating duration method, which means heating in long and short durations alternately without cooling time, is introduced in this paper. Three treatment plans, which are conventional method, unequal heating duration method in linear scanning and unequal heating duration method in spiral scanning, are compared through ablating the same area in simulation. To evaluate the treatment results, the finite element method (FEM) is employed to perform transient thermal analysis and thermal doses are calculated. With the unequal heating duration method, treatment time is reduced by more than 50 percent compared with the conventional method while the target necrosis rate is more than 97 percent. Simulation results show that the unequal heating duration method is effective and promising in HIFU.