Physician’s Brief clinical and research highlights for our colleagues in urology Ye a r- E n d 2014
Histotripsy: Non-invasive, Mechanical Tissue Ablation New U-M-developed technology begins clinical trials A revolutionary method of tissue ablation has now entered early clinical trials at the University of Michigan. This technology, called histotripsy, was conceived by scientists and clinicians at U-M, and it has the potential to treat a wide variety of disorders. Histotripsy is a form of focused ultrasound that uses a mechanical process — not heat, like other focused ultrasound modalities — to ablate tissue. The mechanical process of histotripsy creates extreme pressure changes, causing microbubbles to form in the tissue, a process called cavitation. “When you create very low pressure, dissolved gas and water vapor come out of solution,” explains William W. Roberts, M.D., associate professor of Urology and Biomedical Engineering. “These bubbles oscillate, coalesce and collapse, releasing a tremendous amount of
William Roberts, M.D., combined his expertise in urology and biomedical engineering to pioneer urologic applications of histotripsy.
energy in a very confined space, which mechanically homogenizes the tissue.”
pressure can be precisely confined, allowing non-invasive “sculpting” of tissues.
One of the main advantages to histotripsy is its precision. Most other types of ablation — other forms of ultrasound, radiofrequency and microwave — have trouble controlling the spread of heat. With histotripsy, induced
“Additionally, histotripsy can be viewed in real time during the ablative process, because the microbubbles appear bright white on ultrasound imaging,” says Roberts. “It’s easy to see exactly where the cavitation activity Continued on page 2