Multi-Frequency Focused Ultrasound for Tissue Ablation

In this study, the effectiveness of tissue ablation was investigated using multi-frequency high intensity focused ultrasound (HIFU) transducers (950 kHz, 1.5 MHz). Temperature rise and lesion volume were recorded when chicken tissue was ablated by focused ultrasound (FUS) with controlled ultrasound power and exposure time using single frequency and multi-frequency modes. It was found that multi-frequency tissue ablation gives a higher maximum temperature accompanied by a faster rise, and a larger ablation lesion volume, compared with single frequency ablation, under the same input conditions of electrical power, exposure time and depth of focus. Also, it was concluded that the same desired tissue temperature and ablation lesion conditions can be attained by using less power for the multi-frequency ablation. These findings are promising because the multi-frequency ultrasound ablation using FUS with a greater frequency difference could result in promising imaging guided effective therapy using one multi-frequency probe.