Monte Carlo dosimetry of high dose rate gynecologic interstitial brachytherapy

Maxime Desbiens, Michel D'Amours, Hossein Afsharpour, Frank Verhaegen, Marie-Claude Lavallee, Isabelle Thibault, Eric Vigneault, Luc Beaulieu*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

9 Citations (Web of Science)


Purpose: To assess the dosimetric effects of the presence of the applicator, air pockets in clinical target volume (CTV) and OARs along with tissue heterogeneities using the Monte Carlo (MC) method in high dose rate (HDR) gynecologic interstitial brachytherapy with a Syed-Neblett template. Methods and materials: The CT based dosimetry has been achieved with the Geant4 MC toolkit version 9.2. DICOM-RT files of 38 patients were imported into our own platform for MC simulations. The dose distributions were then compared to those obtained with a conventional TG-43 calculation. Results: Taking account of heterogeneities has effects of the order of 1% on the HDR gynecological dose distributions. However, the exclusion of air pockets and applicator from the DVH calculation can lower the CTV D-90 and V-100 by as much as 8.7% and 5.0% in comparison with TG-43. Rectum dosimetric indices can also be lowered by approximately 3% compared with TG-43 for most cases. Differences for urethra and bladder are for most cases below 1%. Conclusions: Exclusion of non-biological material such as air pockets and applicator volume from the CTV is important for both TG-43 and MC calculations. It could be easily implemented and automated in treatment planning systems without affecting computation times.
Original languageEnglish
Pages (from-to)425-429
JournalRadiotherapy and Oncology
Issue number3
Publication statusPublished - Dec 2013


  • HDR
  • Monte Carlo
  • Brachytherapy
  • Dosimetry
  • Gynecologic

Cite this