Using CBCT to Monitor Treatment Dose Delivery Accuracy in Head and Neck Proton Radiotherapy

Abstract

In comparison with photon radiotherapy, intensity modulated proton therapy (IMPT) has higher sensitivities to anatomical and geometrical changes. In IMPT, variations in tumor size, patient geometry and setup can compromise target coverage or augment dose to nearby organs at risk (OAR). As a result, weekly quality assurance CT scans (QACTs) are commonly used to monitor treatment accuracy and provide indicators for adaptive radiotherapy (ART). This study presents the validation of a tool that applies deformable image registration and image processing techniques to generate accurate noise-free CBCT-based virtual CTs used for proton dose calculation to monitor treatment accuracy in head and neck (HN) patients.