title: Extracorporeal application of high-intensity focused ultrasound for prostatic tissue ablation.
abstract: OBJECTIVE
  To investigate the efficacy and safety of extracorporeal prostatic tissue ablation using high-intensity focused ultrasound (HIFU) in vivo in animals, and in a clinical feasibility study in men, as this is an investigational minimally invasive treatment alternative for locally confined prostatic carcinoma, but may have significant side-effects.
  
  
  METHODS
  Ultrasound (1.04 MHz excitation frequency) was generated by an extracorporeal cylindrical piezo-ceramic element and focused by a paraboloidal reflector to a focal size of 32 x 4 mm. The focal distance and aperture diameter were both 100 mm. HIFU was applied extracorporeally at different intensities and pulse duration (up to 6 s) to 11 dog prostates in vivo (median intensity 1192 W/cm2) and eight patients (median intensity 3278 W/cm2, range 2384-3576) under general anaesthesia. The lesions were assessed macroscopically and histologically after HIFU and any side-effects evaluated.
  
  
  RESULTS
  Thermoablation was feasible in vivo and in all patients. Macroscopic analysis and histology showed sharply demarcated coagulative necrosis. Side-effects, including skin and rectal burns, occurred only after transvesical application in the in vivo study. There were no side-effects in patients after perineal application.
  
  
  CONCLUSIONS
  Extracorporeal HIFU is technically feasible and induces sharply demarcated tissue damage in the prostate. From the early results of this phase 1 study, the perineal approach seems to be safe.
authors.affiliation: Department of Urology, University Hospital Mannheim, Faculty of Clinical Medicine Mannheim, Ruprecht-Karls-University of Heidelberg, Germany. axel.haecker@chir.ma.uni-heidelberg.de
authors.forename: Axel
authors.initials: A
authors.lastname: Häcker
authors.forename: Kai Uwe
authors.initials: KU
authors.lastname: Köhrmann
authors.forename: Walter
authors.initials: W
authors.lastname: Back
authors.forename: Oliver
authors.initials: O
authors.lastname: Kraut
authors.forename: Ernst
authors.initials: E
authors.lastname: Marlinghaus
authors.forename: Peter
authors.initials: P
authors.lastname: Alken
authors.forename: Maurice Stephan
authors.initials: MS
authors.lastname: Michel
mesh_terms: D000818:Animals; D004285:Dogs; D004867:Equipment Design; D005240:Feasibility Studies; D006801:Humans; D008297:Male; D009336:Necrosis; D011468:Prostatectomy / Q000295:instrumentation / Q000379:methods*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000628:therapy*; D014464:Ultrasonic Therapy / Q000295:instrumentation / Q000379:methods*