Dose accumulation after online adaptive MR-guided RT compared to CT-based IGRT in prostate cancer
Date:
Image-guided radiation therapy (IGRT) is standard of care has been used for many years to perform precise irradiation of the target volume and to spare healthy tissue in prostate cancer (PC). The patient position is validated and corrected on the basis of cone-beam computed tomography (CBCT) images acquired on the treatment machine, followed by a rigid registration to the reference anatomy derived from the planning CT. However, this method cannot account for inter-fraction deformations and volume changes, which may be crucial for healthy tissue sparing. Consequently, online adaptive RT techniques, such as magnetic resonance guided radiotherapy (MRgRT) may enable better organ at risk sparing while ensuring high dose coverage of the tumor. The aim of this study was to compare classical IGRT dose delivery using daily imaging to register a reference plan based on pre-treatment planning CT, to online adaptive MRgRT (oa-MRgRT) using deformable dose accumulation techniques in PC. Therefore, a dosimetric comparison of IGRT versus oa-MRgRT was performed.