P2G-2 High Intensity Focused Ultrasound Thermal Therapy for Liver Tumor with Respiration Motion

High intensity focused ultrasound thermal therapy for liver tumor may have a risk of normal tissue damage due to the respiratory motion. The goal of this study is to investigate the thermal dose pattern by using one/two 80-elements linear phased array for liver tumor thermal therapy. The two phased array transducers con-focus at the desired treatment area which is moving due to the respiration. A simple, finite state model of respiratory motion pattern is used to simulate the regular and irregular respiration. An energy deposition algorithm is employed to predict the thermal lesion location. Temperature and thermal dose distributions showed that a better heating can be obtained when the transducer is perpendicular to the respiratory motion direction. The experiment results showed that the thermal lesion location was coincident with that predicted by the energy deposition algorithm. The study revealed that the thermal dose and temperature patterns are highly affected by the respiratory motion and the energy deposition algorithm can be used for the window gating strategy as the high intensity focused ultrasound employed in liver tumor thermal therapy