Boiling activity induced by high intensity focused ultrasound in a tissue-mimicking phantom

The present study aims to investigate experimentally the boiling activity induced by high intensity focused ultrasound (HIFU) in a tissue-mimicking phantom consisting of a polyacrylamide gel mixed with liquid bovine serum albumin by using a dual sensing fiber-optic hydrophone. The HIFU pressure and the HIFU-induced temperature rise near the focus were simultaneously measured for three different focal peak negative pressures. The formation of boiling bubbles during HIFU exposure was observed by using a video camera. Sudden changes in the temperature rise rate and in the frequency spectrogram were found when the boiling bubbles were observed at the focus.