Ex vivo evaluation of high-intensity focused ultrasound with ultrasonic-induced cavitation bubbles.
OBJECTIVE
In high-intensity focused ultrasound (HIFU) comprising high-intensity burst ultrasound (triggering pulse) and medium-intensity continuous wave ultrasound (heating wave), optimizing the effects of the triggering pulse conditions on the coagulated volume may help to reduce treatment times.


METHODS
HIFU combined with a triggering pulse was applied to chicken deep pectoral muscles. The acoustic power of the heating wave was set to 36, 54, or 72 W. Four different triggering pulse conditions were used: heating wave only; or pulse widths and pulse repetition frequencies of 30 μs and 1 kHz, 300 μs, and 100 Hz, or 3 ms and 10 Hz.


RESULTS
Compared to the heating wave only condition, the coagulated volume was significantly larger under all conditions that included a triggering pulse. Significant differences were also observed in the ellipticity of the coagulated region between some conditions.


CONCLUSIONS
HIFU combined with a triggering pulse may play an important role in reducing treatment times.
Joint Graduate School of Tokyo Women's Medical University and Waseda University Cooperative Major in Advanced Biomedical Sciences, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan. abe-n@fuji.waseda.jp.|Application Development Office, Hitachi Medical Corporation, Chiba, Japan. abe-n@fuji.waseda.jp.
Nobutaka
N
Abe
Application Development Office, Hitachi Medical Corporation, Chiba, Japan.
Hidekazu
H
Nakamoto
Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan.
Takashi
T
Suzuki
Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan.
Yoshihiro
Y
Muragaki
Joint Graduate School of Tokyo Women's Medical University and Waseda University Cooperative Major in Advanced Biomedical Sciences, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.|Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan.
Hiroshi
H
Iseki
Cavitation bubbles; High-intensity focused ultrasound (HIFU); High-intensity therapeutic ultrasound (HITU)