A variety of knowledge based planning (KBP) tools have been developed in the literature for treatment plan optimisation and evaluation. These tools assume that current patients can be related to geometrically similar historical patients and can achieve the same dosimetric aims. Current KBP implementations typically consider a single dosimetric predictor such as the geometric relationship between an organ and the PTV. Whilst these implementations may consider multiple organs, the relationship between each individual organ and the PTV is considered in isolation. However, an optimal plan is likely to depend on the complex geometric relationship between multiple organs and the PTV. For example, the level of parotid sparing achievable in a H&N plan may depend to some extent on the proximity of the spinal cord, oral cavity, mandible or any other organ to the PTV rather than just the geometric relationship between the parotid and the PTV.
The aim of this research is to investigate the use of multiple organ KBP tool in which the trade-offs between knowledge based dosimetric predicted doses for multiple organs and targets can be simultaneously considered and used to inform plan optimisation and evaluation.