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Targeted Prostate Thermal Therapy with Catheter-Based Ultrasound Devices and MR Thermal Monitoring

Authors :
Will Nau
Adam M. Kinsey
Chris J. Diederich
Viola Rieke
Graham Sommer
Anthony B. Ross
Kim Butts Pauly
Source :
AIP Conference Proceedings.
Publication Year :
2006
Publisher :
AIP, 2006.

Abstract

Catheter‐based ultrasound devices have significant advantages for thermal therapy procedures, including potential for precise spatial and dynamic control of heating patterns to conform to targeted volumes. Interstitial and transurethral ultrasound applicators, with associated treatment strategies, were developed for thermal ablation of prostate combined with MR thermal monitoring. Four types of multielement transurethral applicators were devised, each with different levels of selectivity and intended therapeutic goals: sectored tubular transducer devices with fixed directional heating patterns; planar and lightly focused curvilinear devices with narrow heating patterns; and multi‐sectored tubular devices capable of dynamic angular control without applicator movement. These devices are integrated with a 4 mm delivery catheter, incorporate an inflatable cooling balloon (10 mm OD) for positioning within the prostate and capable of rotation via an MR‐compatible motor. Similarly, interstitial devices (2.4 mm OD) have been developed for percutaneous implantation with fixed directional heating patterns (e.g., 180 deg.). In vivo experiments in canine prostate (n=15) under MR temperature imaging were used to evaluate the heating technology and develop treatment strategies. MR thermal imaging in a 0.5 T interventional MRI was used to monitor temperature contours and thermal dose in multiple slices through the target volume. Sectored transurethral devices produce directional coagulation zones, extending 15–20 mm radial distance to the outer prostate capsule. The curvilinear applicator produces distinct 2–3 mm wide lesions, and with sequential rotation and modulated dwell time can precisely conform thermal ablation to selected areas or the entire prostate gland. Multi‐sectored transurethral applicators can dynamically control the angular heating profile and target large regions of the gland in short treatment times without applicator manipulation. Interstitial implants with directional devices can be used to effectively ablate the posterior peripheral zone of the gland while protecting the rectum. An implant with multi‐sectored interstitial devices can effectively control the angular heating pattern without applicator rotation. The MR derived 52 °C and lethal thermal dose contours (t43=240 min) allowed for real‐time control of the applicators and effectively defined the extent of thermal damage. Catheter‐based ultrasound devices, combined with MR thermal monitoring, can produce relatively fast and precise thermal ablation of prostate, with potential for treatment of cancer or BPH.

Details

ISSN :
0094243X
Database :
OpenAIRE
Journal :
AIP Conference Proceedings
Accession number :
edsair.doi...........1946b2ea1ae601f3b693561010588f57
Full Text :
https://doi.org/10.1063/1.2205499