Constructive and GRASP Approaches to Radiotherapy Treatment Scheduling

With the increase in the number of cancer cases and new government regulations for cancer treatment, radiotherapy scheduling has gained a lot of importance recently. In this paper, four constructive approaches to radiotherapy scheduling are introduced, which investigates effects of changing the following parameters on the schedule performance: (1) changing the day to serve as startup point in the search for the scheduling of the patient´s sessions, (2) changing the threshold on machine capacity for patients of different category, (3) changing the frequency of scheduling and (4) changing the time distance from the waiting time targets of patients of different categories to the day when a schedule can be created. In addition, a GRASP based algorithm is developed for improving the solution obtained by the constructive approaches. These algorithms are investigated on real-world data obtained from the Nottingham University Hospitals NHS Trust, UK.