Study of ultrasound contrast agents in 1.2MHz focused ultrasound field based on sonochemiluminescence

Focused ultrasound (FU), especially high intensity focused ultrasound (HIFU) is a very promising therapeutic method due to its non-invasive and efficient character. Ultrasound contrast agents (UCAs) are frequently added into HIFU field as cavitation nuclei to enhance the therapeutic efficiency. However, their presence will distort the pressure field, shield the initial target and make the process unpredictable. In order to better monitor and use UCAs, their behavior, especially the active zone spatial distribution in ultrasound field must be understood. The aim of this work was to study the UCAs influence on the active zone distribution. The UCAs in a 1.2MHz focused ultrasound field were studied by Sonochemiluminescence method, which is a very direct indicator of active inertial cavitation, and compared with control group. It was obviously that the UCAs can reduce the SCL threshold, and appeared a different SCL distribution from the control group. At the power lower than 50w, the pre-focal region had brighter SCL than control group. At the power beyond 50w the SCL intensity raised sharply in post-focal region, while pre-focal region has a lower SCL intensity compared to control group.