Multi-target Tracking in Prostate Radiotherapy Using MLC and KIM

This study will assess the feasibility of implementing real-time multi-leaf collimator (MLC) tracking to account for the relative motion of the moving prostate tumour target and the static pelvic nodal target for high-risk prostate cancer patients. The capability of tracking for the relative motion of multiple targets will ensure that all the treatment targets receive correct dose as prescribed by the doctor and minimising side effects to the critical organs. During radiation treatment, the prostate position will be monitored in real time using the KIM technology. The nodal target will be imaged before and after each treatment to evaluate the nodal treatment margin. The MLC tracking is implemented by recalculating the radiation beam shape fit for the moved prostate and static nodal targets and sending the adjusted MLC leaf positions to the treatment delivery system. The actually delivered dose to the patient will be calculated after the treatment and compared to the dose without MLC tracking to assess the treatment efficacy.