Comparison of split-beam transducer geometries and excitation configurations for transrectal prostate HIFU treatments

Six split-beam transducer configurations have been examined using computer simulations and in-vitro experiments. The goal of this study was to identify a simple split-beam transducer configuration capable of reducing transrectal high intensity focused ultrasound (HIFU) prostate cancer treatment time without sacrificing treatment safety and efficacy. Lesion volume, lesion and rectal wall temperatures, sonication ON/OFF time, and total acoustic power parameters were used as comparison criteria. The most promising split-beam configuration generates necrosed tissue volumes 5 times larger than the single-element transducer with the same sonication time, while keeping maximum focal zone temperatures below 90°C. These parameters yield approximate overall treatment time reductions by a factor of 1.85 as compared to single-element transrectal HIFU PC treatments, mainly due to longer tissue cooling time required to maintain current safety levels