Experimental evaluation of targeting accuracy of a B-mode ultrasound-guided phased-array focused ultrasound system using a thermocouple array

Image-guide high-intensity focused ultrasound (HIFU) has been widely used in the treatment of uterine fibroids. However, before HIFU system is ready for use, the targeting accuracy should be known for the safety of important abdominal organs surrounding the target. Researchers have used magnetic resonance (MR) images or computed tomography (CT) to evaluate the targeting accuracy of current MR-guided HIFU systems, whereas these methods cannot be directly used in the ultrasound-guided HIFU (USgHIFU) systems. In this study, a thermocouple array is used in combination with the in-house built acrylic plate to evaluate the targeting accuracy of the existing 112-channel phased-array USgHIFU system. The results of ex vivo experiment demonstrate the feasibility and the efficacy of the thermocouple array in the evaluation, and the targeting accuracy of the USgHIFU system is about 1mm in the focal plane. Thus, this accuracy is adequate for the treatment of uterine fibroids.