Medical and Biological Physics(DMBP)
Physique médicale et biologique (DPMB)
Robert CLARKE
Carleton University
High Intensity Focused Ultrasound for Non-invasive Therapy
The last decade has seen significant advances in the application of high intensity focused ultrasound (HIFU) for the treatment of deep-seated localized cancer. Beams of up to several hundred watts, 1 to 3 MHz, can be focused to elliptical volumes, 0.2 cm diameter by 2 cm long, and directed to sites up to 8 cm below the skin surface, without superficial damage. The resulting intensites can completely destroy cancer tissue within a few seconds. By stepping the beam over the extended region, complete destruction can be achieved. Liver, prostate and pancreas have been the sites most often partially or wholly treated. Phse II trials of about 100 patients in the UK, more in the US and Europe, and more than 1000 in China are now complete. Treatment is essentially conformal, and depends to a great degree on the associated imaging techniques, mainly MRI and ultrasound.