Development of temperature controller-integrated portable HIFU driver for thermal coagulation

Abstract

BackgroundTemperature monitoring during high-intensity focused ultrasound (HIFU) therapy on tissue is essential to regulate the degree of thermal coagulation and to achieve the desired treatment outcomes eventually. The aim of the current study was to design and investigate the feasibility of a proportional-integral-derivative (PID) temperature controller-integrated portable HIFU driver for thermal coagulation.MethodsA portable HIFU driver was designed and operated at a maximum output voltage of 50V with pulse-width modulation signals at 2MHz. The temperature of ex vivo bovine liver tissue was monitored using a K-type thermocouple during the 2-MHz HIFU exposure.ResultsThe tissue temperature was maintained at 60 degrees C using a PID controller-integrated HIFU driver that modulated the output voltage during the 300-s HIFU exposure. The ex vivo testing demonstrated that the tissue temperature at the focal point approached the chosen temperature, i.e., 60 degrees C, within 70s. The temperature was maintained with a deviation of less than 4 degrees C until the HIFU driver voltage was turned off at 300s.ConclusionsThe designed PID controller-integrated HIFU driver can be used as a small portable tool to regulate the tissue temperature in real time and achieve thermal coagulation via HIFU sonication.