Real-time source tracking for quality assurance in HDR prostate brachytherapy

High dose rate (HDR) brachytherapy is the preferred treatment option for clinically localised prostate cancer. The underlying principle is simple: temporarily inserting a highly radioactive source inside the target volume and moving it through a sequence of predefined positions for pre-calculated dwell times. HDR brachytherapy is capable of achieving a highly conformal dose distribution which cannot be matched by external beam radiation therapy.