Real-Time Visual Tracking of the HDR Source during Skin Therapy Enabled by Scintillation Markers

Abstract

The most frequent cause of high dose rate (HDR) brachytherapy medical events is incorrect measurement and/or entering of catheter length in the treatment planning system. Another common cause of medical events is the incorrect connection of catheters, transfer tubes and afterloader channels at the treatment. These errors displace the HDR source from its planned position up to a distance of 30 cm away from the treatment target [1], Resulting in dosimetric errors that under-dose, or completely miss, the treatment target and increase dose to healthy tissue. For the treatment of complex superficial skin lesions, the probability of these errors is increased due to the complex shape of the surface applicator and numerous catheters required for these treatments. Current quality assurance methods aim to prevent these errors from occurring prior to treatment by relying on manual checks and verbal verification between physicians, therapists and physicists. Despite these efforts, there remain a lack of methods to verify the HDR source position during treatment to ensure that radiation is being delivered correctly and prevent misadministration. Here, we developed a method for visual real-time tracking of the source to overcome the inadequacies of the present QA processes.