Advancing Prostate Cancer Treatment: A Review of CT and MR-Guided Online Adaptive Radiotherapy Techniques

Radiotherapy remains a cornerstone in the management of prostate cancer (PCa) with continuous technological advancements significantly improving precision and reducing treatment-related toxicity. Among these innovations, adaptive radiotherapy (ART) is revolutionizing the field by enhancing treatment precision through advanced imaging, real-time motion tracking, and on-table adaptive planning. ART carries the potential to optimize therapeutic outcomes by adjusting radiation dose in response to anatomical changes that previously could not be accounted for, thus minimizing damage to healthy tissue and increasing the delivery of dose to therapeutic targets. Magnetic resonance (MR) and computed tomography (CT) imaging have played pivotal roles in ART by providing detailed anatomical and functional insights for treatment planning and realtime guidance. This review explores the technical principles, clinical applications, and recent technological developments of ART in the management of PCa. It describes both offline and online ART workflows and compares CT-guided and MR-guided approaches, outlining how each modality enhances the precision of radiation delivery through improved visualization, auto-segmentation, and plan adaptation capabilities. As ART technologies continue to evolve, these imaging-guided modalities are poised to refine prostate RT by enabling safer dose escalation, minimized toxicity, and ultimately, improved patient outcomes.