Radiation therapy simulation and optimization using kinetic polygon modeling

Intensity modulated radiotherapy (IMRT) is a treatment for various cancers that involves applying a beam of radiation to diseased tumor cells. Although effective at destroying cancerous tissue, physicians must take care to avoid healthy tissues during the treatment plan as these may also be damaged. To improve treatment, computational methods are often employed to allow treatment planners to track the target tumor and apply radiation when it is less obstructed by healthy organs and tissues and thus more exposed to the beam, maximizing the damage to the diseased cells while minimizing the harm to healthy cells. Internal organs and tissues are rarely static, so this optimal time frame can be challenging to pinpoint. In this paper we develop a novel algorithm and accompanying data structure to determine the point in time at which the tumor target is most exposed. By modeling the organs and tumor as a set of moving polygons in the beam´s eye view and using a kinetic data structure to track the level of exposure of the tumor as organs in the treatment area move, healthy tissue can be protected and the tumor can be targeted with greater effectiveness and precision, thus improving the overall quality of treatment.