114 超音波音場における微小気泡の熱的及び音響的作用(S33-3 マイクロ気泡・粒子,S33 マイクロ・ナノフルイディクス)  [in Japanese] 114 Thermal and Acoustic Effect of Microbubbles in the Ultrasound Field  [in Japanese]

Recently, industiral and medical applications which employ microbubbles have been the subject of much interest. Especially in the medical field, ultrasound imaging, sonodynamic therapy, gene therapy and heat coagulation of tumor are being investigated. In the field of bubble dynamics, it is known that bubbles play a role in converting the mechanical energy of an ultrasound wave into not only energy of acoustic emission but also heat energy deposition when they are subjected to an oscillating field. The kind of gas inside a bubble has a strong effect on the energy deposition from the bubbles. We conducted two types of experiments for the analysis of the thermal and acoustic properties of different types of gas bubble, and the relationship between the gas properties and radiation energies from bubbles are discussed. It is concluded that the balance between heat deposition and acoustic emission from the bubbles can be changed by changing the gas inside the bubbles.