Optimizing Planning and Delivery of High-Precision Robotic Radiotherapy and Intensity-Modulated Proton Therapy

Abstract

High-precision robotic radiotherapy and intensity-modulated proton therapy (IMPT) are two relatively new radiotherapy techniques that particularly aim at a highly localized delivery of a curative dose to the tumor, while achieving excellent sparing of the surrounding healthy tissues and critical organs. However, the use of hundreds (in high-precision robotic radiotherapy) or thousands (in IMPT) of small radiation beams to achieve a highly localized dose delivery is also associated with a number of issues regarding the efficiency and accuracy of treatment planning and delivery. These issues currently obstruct a more widespread use of high-precision robotic radiotherapy and IMPT. In this thesis, we have aimed at improving treatment planning and treatment delivery for both treatment modalities in order to overcome these obstacles. We have developed and evaluated several methods to reduce the treatment delivery time and the treatment planning time. This resulted in average delivery time reductions of 16%–38% and optimization times to be shortened by a factor of 2.8–5.6 on average. Next to that, we have investigated for both treatment modalities the sensitivity to treatment uncertainties and the effectiveness of techniques to reduce treatment errors or their impact on the delivered dose. This allowed us to establish favorable treatment strategies to achieve adequate dose delivery in the presence of intrafraction tumor motion and uncertainties in patient position, patient anatomy and proton range (for IMPT). These efforts will contribute to a more efficient, effective and safe delivery of a highly localized dose to the tumor using the CyberKnife and IMPT.