A feasibility study for the non-invasive treatment of superficial bladder tumours with focused ultrasound.
OBJECTIVE
To determine whether high-intensity focused ultrasound can be used to ablate bladder wall tissue using a transabdominal approach in a large animal model, and whether it can be developed as a non-invasive treatment for superficial bladder tumours.


METHODS
The bladder wall of 25 large white pigs was treated with a 1.7 MHz extracorporeal focused-bowl ultrasonic transducer. Animals were killed either 2 h, 3 days or 4 weeks after treatment and the bladder wall examined macroscopically and histologically.


RESULTS
Acute bladder wall damage was detected in 15 of 16 animals at 2 h and in all six animals examined after 3 days. Areas of healing were seen in 10 of 12 animals at 4 weeks. Histological analysis of the treated areas revealed that the urothelium was denuded within 2 h and was associated with an acute inflammatory response in the bladder wall. At 4 weeks, the urothelium had regenerated over a maturing scar.


CONCLUSIONS
Focused ultrasound can be used successfully to destroy regions of the bladder wall in a large animal model in vivo.
Watkin
N A
NA
Department of Physics, Institute of Cancer Research, Sutton, UK.
Morris
S B
SB
Rivens
I H
IH
Woodhouse
C R
CR
ter Haar
G R
GR
D000818:Animals; D003556:Cystitis / Q000209:etiology / Q000473:pathology; D013552:Swine; D014464:Ultrasonic Therapy / Q000379:methods*; D001749:Urinary Bladder Neoplasms / Q000473:pathology / Q000628:therapy*