Radiation therapy is extensively used to treat a wide range of cancers. Due to the increasing complexities of delivery mechanisms, and the improved imaging devices that allow more accurate determination of cancer location, determination of high quality treatment plans via trial-and-error methods is impractical and computer optimization approaches to planning are becoming more critical and more difficult.We outline three examples of the types of treatment planning problem that can arise in practice and strive to understand the commonalities and differences in these problems. We highlight optimization approaches to the problems, and particularly consider approaches based on mixed integer programming. Details of the mathematical formulations and algorithmic approaches are developed and pointers are given to supporting literature that shows the efficacy of the approaches in practical situations.