Upright Proton Therapy Compared to Supine Positioning: A Systematic Review on Applications and Dosimetric Plan Quality

Background: Recent advancements in radiotherapy have led to renewed interest in upright patient positioning, particularly in particle therapy and photon-based external beam radiotherapy. Historically, upright treatments were used in specialized therapies, such as boron neutron capture therapy and proton therapy, but were largely abandoned due to the standardization of supine imaging and treatment workflows. However, technological improvements, such as upright CT and MRI imaging, alongside enhanced immobilization techniques, are facilitating a reassessment of upright treatments. This study aims to provide a review of upright proton therapy (UPT) compared to traditional treatments in the supine position. Materials and Methods: A comprehensive search of PubMed, Science Direct, Web of Science, and Google Scholar databases up to January ۲۰۲۵ was conducted. Various combinations of keywords including "cancer", "upright radiotherapy technique", "proton therapy", "dosimetric plan quality", and "treatment quality" were utilized. Finally, ۱۰ articles most recent and relevant records were included in the study. Results: Studies highlight the efficacy of UPT for head and neck, thoracic, and skull-base tumors, demonstrating improved accessibility, cost-effectiveness, and reduced toxicity. UPT enhances set-up reproducibility and stability, particularly in thoracic treatments, where internal organ shifts impact dose distribution. Furthermore, compact, gantry-less designs contribute to cost reduction, making proton therapy more accessible. Despite these advantages, challenges remain, including the need for optimized immobilization techniques and workflow adaptation. Conclusion: Comparative analysis with traditional supine radiation therapy underscores the potential of UPT for superior tumor targeting and dosimetric benefits, though further clinical validation is required.

Keywords:

Upright Proton Therapy , Plan Quality , Patient Positioning , Cancer