Transurethral high intensity focused ultrasound: catheter based prototypes and experimental results

Transurethral catheters containing multiple high-intensity focused ultrasound (HIFU) transducers at their tip have been designed, built and tested for the treatment of prostate tissue. These catheters address a need in the medical community for simple, fast, and effective treatments using low-cost, disposable, and application-specific devices for disease control through tissue ablation. The HIFU transducers used in the transurethral catheter prototypes have a focal length of 10 mm, operate at 5 MHz, and are able to generate total acoustic power levels exceeding 8 Watts. Experimental in vitro and in vivo results show that the catheters can ablate cylindrical tissue volumes >5 cm/sup 3/ around the urethra in less than 15 minutes through simple catheter rotation. These results indicate that catheter-based HIFU transducers can be used to provide a viable alternative to current minimally-invasive therapies for prostate diseases, such as BPH. The technologies also show promise for the treatment of other diseases that would benefit from using small, minimally invasive HIFU transducers (such as esophageal, thoracic, and ear/nose/throat and OB/Gyn applications). Catheter prototypes are described, and in vitro, in vivo, and histology data are presented.