Ultrasound energy can be focused with exquisite precision to produce temperatures hotter than 65 degrees within a few seconds. The focus is so sharp that areas outside it—even those a fraction of an inch away—are not heated or damaged. The ultrasound works like a scalpel (and in this precision, HIFU has a key advantage over microwave therapy). The HIFU selectively blasts BPH tissue; like the hottest TUMT therapy, it can form cavities in the prostate. Over time, this tissue liquefies and is reabsorbed by the body or flushed out during urination. With such high temperatures, some form of anesthesia (spinal or local) is needed during the procedure.

There have been very few side effects to this procedure, the main one being temporary urinary retention in most men. Early studies of HIFU in animals and men have been promising. One highly sophisticated HIFU unit currently being tested (called Sonablate) comes equipped with a rectal probe that uses ultrasound to map out the prostatic urethra.

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