Real-time visualization of high-intensity focused ultrasound treatment using ultrasound imaging

High-intensity focused ultrasound (HIFU) and conventional B-mode ultrasound (US) imaging were synchronized to develop a system for real-time visualiza tion of HIFU treatment. The system was tested in vivo in pig liver. The HIF U application resulted in the appearance of a hyperechoic spot at the focus that faded gradually after cessation of HIFU exposure. The duration of HIF U exposure needed for a hyperechoic spot to appear, was inversely related t o the HIFU intensity. The threshold intensity required to produce a hyperec hoic spot in liver in < is was 970 W/cm(2), in situ. At this HIFU dose, no immediate cellular damage was observed, providing a potential for pretreatm ent targeting. The real-time visualization method was used in hemostasis of actively bleeding internal pelvic vessels, allowing targeting and monitori ng of successful treatment. Real-time US imaging may provide a useful tool for image-guided HIFU therapy. CE-mail: adasi@u.washington.edu) (C) 2001 Wo rld Federation for Ultrasound in Medicine & Biology.