Development of HIFU treatment in which the heating location is controlled using microbubbles

Kenichi Kajiyama, Naoyuki Iida, Keisuke Hasegawa, Shin Yoshizawa, Kiyoshi Yoshinaka, Shu Takagi, Yoichiro Matsumoto

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


High-intensity focused ultrasound (HIFU) treatment that employs microbubbles to provide enhanced heating has been investigated in order to develop a less invasive and more rapid tumor therapy. Previous studies by us have demonstrated that ultrasound propagation is disturbed when there are microbubbles in front of the focus. In this study, we develop a method for obtaining enhanced heating by using microbubbles just at the focus, thus avoiding heating on the transducer side. In this method, microbubbles are destroyed in front of the HIFU focus (on the transducer side) by irradiating a very short burst wave of microsecond order, before irradiating the ultrasound waves for heating the focus. The experiment is conducted in a medium of a gel containing microbubbles, and a temperature-sensing liquid crystal sheet is set in the focus to observe the temperature distribution. The ultrasound frequency was 2.2 MHz and the intensity was 5000 W/cm 2, and 20 burst wave waves were irradiated at pulse repetition frequency of 1 kHz. The number of wave pulses was varied. The continuous-wave frequency, intensity and irradiation time are 2.2 MHz, 1000 W/cm 2 and 60 sec, espectively. As the number of pulses increased, the heating region moves from the transducer side to the focus. This is because microbubbles in front of the focus are destroyed and the ultrasound propagates around the target position effectively. These results suggest that the microbubble distribution and the heating position in the developed HIFU system can be controlled.

Original languageEnglish
Title of host publication8th International Symposium on Therapeutic Ultrasound
Number of pages5
Publication statusPublished - 2009
Event8th International Symposium on Therapeutic Ultrasound - Minneapolis, MN, United States
Duration: 2008 Sept 102008 Sept 13

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Conference8th International Symposium on Therapeutic Ultrasound
Country/TerritoryUnited States
CityMinneapolis, MN


  • Gel
  • HIFU
  • Microbubble
  • Temperature rise


Dive into the research topics of 'Development of HIFU treatment in which the heating location is controlled using microbubbles'. Together they form a unique fingerprint.

Cite this