Brachyview: An in-body imaging system for real-time QA in HDR prostate brachytherapy

A transrectal real-time source tracking system, BrachyView, is developed by Centre for Medical Radiation Physics at University of Wollongong for treatment quality control during the high dose rate prostate brachytherapy procedure (HDR-PBT). The probe consists of a 15 × 60 mm² pixellated silicon detector (four Timepix detectors) encased in a cylindrical seven pinhole tungsten collimator. The source position is determined by back-projecting the source projection images through the collimator pinholes. A prototype BrachyView probe consisting of a single Timepix detector (15 × 15 mm²) and a planar seven pinhole collimator is evaluated in this paper. The source position can be estimated with a maximum error of 0.2 mm on the detector plane, which translates into a maximum error of 1.42 mm within the prostate volume. This result is in good agreement with the results obtained in previously published simulation studies.