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Image-guided radiotherapy using 2D and 3D ultrasound combined with Monte Carlo dose calculations in prostate treatments

Two ultrasound systems were studied to investigate the effects of positional and volumetric prostate variations on dosimetry over the course of external radiation therapy. A 2D system, currently used at the Montreal General Hospital for patient repositioning, was compared to a 3D system invented recently. Prostate variations were quantified from ultrasound images acquired daily during a 2003 clinical study. A method was devised to introduce ultrasound information in a Monte Carlo Treatment Planning System previously developed at McGill. Patient repositioning was evaluated for both systems using dose-volume histograms of Voxel Monte Carlo dose calculation. Repositioning with the 3D system, neglecting volume changes, was found to bring the target dose to within 1 % of the planned dose, rather than the 12 % of the clinical 2D system. However, when considering the varying 3D volumes, the dose could only be corrected to within 7 %. These results indicate that the 3D system provides not only a more accurate assessment of prostate displacements, but also volumetric information that significantly affects the dosimetry.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.98761
Date January 2005
CreatorsMark, Clarisse Ildikó.
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageMaster of Science (Department of Medical Radiation Physics.)
Rights© Clarisse Ildikó Mark, 2005
Relationalephsysno: 002332458, proquestno: AAIMR24733, Theses scanned by UMI/ProQuest.

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