An Enhanced Iterated Greedy Metaheuristic for the Particle Therapy Patient Scheduling Problem1

The Particle Therapy Patient Scheduling Problem (PTPSP) arises in modern cancer treatment facilities that provide particle therapy and consists of scheduling a set of therapies within a planning horizon of several months. A particularity of PTPSP compared to classical radiotherapy scheduling is that therapies need not only be assigned to days but also scheduled within each day to account for the more complicated operational scenario. In an earlier work we introduced this novel problem setting and provided first algorithms including an Iterated Greedy (IG) metaheuristic. In this work we build upon this IG and exchange two main components: the construction phase and the local search algorithm. The resulting metaheuristic enhances the existing approach and yields in most of the considered benchmark instances substantially better results.