Extracorporeal application of high-intensity focused ultrasound for prostatic tissue ablation.
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.
Häcker
Axel
A
Department of Urology, University Hospital Mannheim, Faculty of Clinical Medicine Mannheim, Ruprecht-Karls-University of Heidelberg, Germany. axel.haecker@chir.ma.uni-heidelberg.de
Köhrmann
Kai Uwe
KU
Back
Walter
W
Kraut
Oliver
O
Marlinghaus
Ernst
E
Alken
Peter
P
Michel
Maurice Stephan
MS
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*