High Intensity Focused Ultrasound (HIFU) in urology.

Introduction: Focused ultrasound is now well known to urologists in the con text of its validated application in extracorporeal lithotripsy. High Inten sity Focused Ultrasound (HIFU) represents a potential therapeutic modality for tissue destruction due to its very high energy and its capacity to prec isely reach a target with a very short emission time. The authors review th e current state of art of HIFU in urology at a time when its indication in prostate cancer is being defined. Material and Method: After a brief description of the main physical princip les of ultrasound and the main data determining focussing of high energy ul trasound, the main machines available (research and clinical) are described . The published clinical literature concerning the tissue destructive actio n in urology is reviewed. Results: HIFU has been used in urology to treat renal, vesical, prostatic ( BPH and cancer), and external genital organ lesions. Purely extracorporeal machines are gradually being replaced by intracorporeal procedures, especia lly transrectal techniques for prostatic lesions. The quality of ultrasound detection of the target still limits the use of this minimally invasive mo dality. The intervening tissues are spared with a good therapeutic efficacy on the target tissues, provided optimal firing parameters are used. Conclusion: HIFU has a demonstrated potential in the treatment of prostate cancer and studies conducted by several teams have defined the technique an d its efficacy. Other indications have been studied, but must be validated by further clinical trials. The future will probably see the design of mach ines adapted to a specific target tissue rather than a single multidiscipli nary extracorporeal machine.