RESUMO
PURPOSE: This project aimed to determine the adequacy and accuracy of high-intensity focused ultrasound(HIFU) for ablating canine model of benign prostate hyperplasia and to assess the therapeutic results. MATERIALS AND METHODS: Using the developed transrectal type HIFU transducer, exposure time-temperature curves were obtained. In-vitro experiments were performed on calf muscle tissues and characteristics of coagulative lesions were observed. In-vivo experiments were performed on canine prostate, which were evaluated grossly, histologically, and ultrasonographically. Complications and side effects were assessed by blood chemistry and urinalysis. RESULTS: The peak temperature reached to 93.0+/-3.0degrees C within initial 11 seconds at the focused area. The mean thermal elevation was 56.0+/-3.0degrees C. In in-vitro HIFU experiments, the coagulative lesions were observed at the focused areas of muscle tissues. The lesions were ellipsoidal shaped, 5.0+/-2.0mm diameter, well delinated. In animal experiments, the affected canine prostates were shown definite lesions of coagulative necrosis which were confirmed grossly and histologically. Significant side effects or complications were not assessed. CONCLUSIONS: Transrectal HIFU treatment may be considered as safe, effective technique on prostate. It is neccessary to perform long-term animal experiments and clinical trials.