Feasibility study of ultrasonic computed tomography-guided high-intensity focused ultrasound

The aim of this study was to establish a proof of concept for an ultrasonic image-guided high-intensity focused ultrasound (HIFU) breast treatment system. An ultrasonic computed tomography (UCT) scanner served as a platform for image acquisition and thermal mapping. With this system, images depicting the speed of sound (SOS) can be obtained. After HIFU activation, the resulting changes in SOS can be mapped. For the temperature range T ≤ 45°C, the temperature elevation is obtained directly from the change in SOS. For thermal ablation, monitoring is obtained by studying the temporal derivative of the SOS while continuous HIFU heating is applied. The method was implemented to in vitro tissue specimens and the ability for thermal monitoring was demonstrated. The results indicate that the suggested concept is indeed feasible.