A method of introducing cooling time between multiple sonications in focused ultrasound surgery

The conventional treatment method involves the introduction of cooling time between individual sonications to avoid near-field heating in focused ultrasound surgery. This approach considerably prolongs treatment time. In this paper, a method of introducing cooling intervals between multiple continuous sonications is proposed to reduce treatment time. Pulse durations were determined by the simulation before hyperthermia. Simulations and ex vivo experiments were conducted using the conventional and proposed methods for three targets of different size (2, 4, and 16 spot). The simulated and experimental results both show that the proposed method not only decreases treatment time, but also improves near-field safety which produces lesions with much shorter axial lengths. The effects of cooling interval, consecutive pulse numbers, and scanning path are also discussed.