Dose compensation algorithm in radiotherapy planning

Abstract

Pauses in radiotherapy treatment is a significant problem that affects overall treatment time - a predictor of tumor proliferation and definitive patient outcome and demands a decisionmaking tool for optimizing doses between healthy tissue and target volumes. During prolonged radiotherapy interruptions, linear-quadratic model showed inadequacy in predicting tumor proliferation. We have developed a radiobiology algorithm applied for dose compensating, providing multiple options for dose compensating due to prolonged pauses. Based on linear-quadratic (LQ) model providing, in specific cases, orientational values for tumors and organs at risk (OAR), we developed a radiobiology calculator that can be used in dose compensation, giving more than one option in correcting biological effective dose (BED) due to prolonged pauses. Generic OAR offers the opportunity to individualize α/β ratio for any organ at risk or tumor. Seven cancer patients who experienced radiotherapy treatment delays, for more than two weeks, are included in this research. The developed algorithm offers the radiation oncologist optimal modality choice and can be a helpful tool for overcoming long delays, except for patients whose treatment interruptions occur at the end of radiation treatment and for patients with fast proliferating tumors. During this course of treatment, none of the included patients manifested severe acute radiotherapy adverse events. The dose compensating algorithm can be a useful tool for dose calculations with optimal healthy tissue sparing, but large prospective studies are necessary to confirm the benefit.