Investigation of parameters affecting treatment time in MRI-guided transurethral ultrasound therapy

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

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

1 Scopus citations

Abstract

MRI-guided transurethral ultrasound therapy shows promise for minimally invasive treatment of localized prostate cancer. Real-time MR temperature feedback enables the 3D control of thermal therapy to define an accurate region within the prostate. Previous in-vivo canine studies showed the feasibility of this method using transurethral planar transducers. The aim of this simulation study was to reduce the procedure time, while maintaining treatment accuracy by investigating new combinations of treatment parameters. A numerical model was used to simulate a multi-element heating applicator rotating inside the urethra in 10 human prostates. Acoustic power and rotation rate were varied based on the feedback of the temperature in the prostate. Several parameters were investigated for improving the treatment time. Maximum acoustic power and rotation rate were optimized interdependently as a function of prostate radius and transducer operating frequency, while avoiding temperatures >90°C in the prostate. Other trials were performed on each parameter separately, with the other parameter fixed. The concept of using dual-frequency transducers was studied, using the fundamental frequency or the 3rd harmonic component depending on the prostate radius. The maximum acoustic power which could be used decreased as a function of the prostate radius and the frequency. Decreasing the frequency (9.7-3.0 MHz) or increasing the power (10-20 W.cm-2) led to treatment times shorter by up to 50% under appropriate conditions. Dual-frequency configurations, while helpful, tended to have less impact on treatment times. Treatment accuracy was maintained and critical adjacent tissues like the rectal wall remained protected. The interdependence between power and frequency may require integrating multi-parametric functions inside the controller for future optimizations. As a first approach, however, even slight modifications of key parameters can be sufficient to reduce treatment time.

Original languageEnglish (US)
Title of host publication9th International Symposium on Therapeutic Ultrasound - ISTU 2009
Pages323-326
Number of pages4
DOIs
StatePublished - Mar 30 2010
Event9th International Symposium on Therapeutic Ultrasound, ISTU 2009 - Aix-en-Provence, France
Duration: Sep 24 2009Sep 26 2009

Publication series

NameAIP Conference Proceedings
Volume1215
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

Other9th International Symposium on Therapeutic Ultrasound, ISTU 2009
CountryFrance
CityAix-en-Provence
Period9/24/099/26/09

Keywords

  • Mini-invasive
  • Prostate
  • Temperature feedback controller
  • Thermal therapy
  • Transurethral
  • Ultrasound

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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  • Cite this

    N'Djin, W. A., Burtnyk, M., Chopra, R., & Bronskill, M. J. (2010). Investigation of parameters affecting treatment time in MRI-guided transurethral ultrasound therapy. In 9th International Symposium on Therapeutic Ultrasound - ISTU 2009 (pp. 323-326). (AIP Conference Proceedings; Vol. 1215). https://doi.org/10.1063/1.3367172