3D conformal MRI-guided transurethral ultrasound therapy: Results of gel phantom experiments

W. A. N'Djin, M. Burtnyk, S. McCormick, M. Bronskill, R. Chopra

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

MRI-guided transurethral ultrasound therapy shows promise for minimally invasive treatment of localized prostate cancer. Previous in-vivo studies demonstrated the feasibility of performing conservative treatments using real-time temperature feedback to control accurately the establishment of coagulative lesions within circumscribed prostate regions. This in-vitro study tested device configuration and control options for achieving full prostate treatments. A multi-channel MRI compatible ultrasound therapy system was evaluated in gel phantoms using 3 canine prostate models. Prostate profiles were 5mm-step-segmented from T2-weighted MR images performed during previous in-vivo experiments. During ultrasound exposures, each ultrasound element was controlled independently by the 3D controller. Decisions on acoustic power, frequency, and device rotation rate were made in real time based on MR thermometry feedback and prostate radii. Low and high power treatment approaches using maximum acoustic powers of 10 or 20 W.cm-2 were tested as well as single and dual-frequency strategies (4.05/13.10 MHz). The dual-frequency strategy used either the fundamental frequency or the 3rd harmonic component, depending on the prostate radius. The 20 W.cm-2 dual frequency approach was the most efficient configuration in achieving full prostate treatments. Treatment times were about half the duration of those performed with 10 W.cm-2 configurations. Full prostate coagulations were performed in 16.3 ± 6.1 min at a rate of 1.8 ± 0.2 cm3.min-1, and resulted in very little undertreated tissue (< 3%). Surrounding organs positioned beyond a safety distance of 1.4 ± 1.0 mm from prostate boundaries were not damaged, particularly rectal wall tissues. In this study, a 3D, MR-thermometry-guided transurethral ultrasound therapy was validated in vitro in a tissue-mimicking phantom for performing full prostate treatment. A dualfrequency configuration with 20 W.cm-2 ultrasound intensity exposure showed good results with direct application to full human prostate treatments.

Original languageEnglish (US)
Title of host publication10th International Symposium on Therapeutic Ultrasound, ISTU 2010
Pages132-137
Number of pages6
DOIs
StatePublished - Oct 13 2011
Event10th International Symposium on Therapeutic Ultrasound, ISTU 2010 - Tokyo, Japan
Duration: Jun 9 2010Jun 12 2010

Publication series

NameAIP Conference Proceedings
Volume1359
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

Other10th International Symposium on Therapeutic Ultrasound, ISTU 2010
CountryJapan
CityTokyo
Period6/9/106/12/10

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Keywords

  • 3D temperature feedback controller
  • Cancer
  • Canine prostate
  • Mini-invasive
  • Thermal therapy
  • Transurethral
  • Ultrasound

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

N'Djin, W. A., Burtnyk, M., McCormick, S., Bronskill, M., & Chopra, R. (2011). 3D conformal MRI-guided transurethral ultrasound therapy: Results of gel phantom experiments. In 10th International Symposium on Therapeutic Ultrasound, ISTU 2010 (pp. 132-137). (AIP Conference Proceedings; Vol. 1359). https://doi.org/10.1063/1.3607894