ESTRO 2025 - Abstract Book

S4033

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2025

Conclusion: Overall there was a noticeable reduction in the number of unsuccessful CT scans with the introduction of the pre habilitation constipation assessment. Therefore the introduction of this intervention can result in a significant reduction in lost capacity due to unsuccessful planning CT scans.

Keywords: Constipation, Pre-hab, Laxatives

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Digital Poster Effect of Patient’s Arm Sparing on the Dosimetry of Cyberknife Spine Cases with Arms-Down Position Wing Sze Wong, Tin Lok Chiu, Siu Ki Yu Medical Physics Department, Hong Kong Sanatorium & Hospital, Hong Kong, Hong Kong Purpose/Objective: CyberKnife is increasingly applied in radiotherapy for spinal tumors. To improve the patient stability and optimize the safety zone area around the patient, patients are immobilized in an arms-down, supine position. To minimize the arm dose, the entrance beams to the arms can be restricted by setting the beam intersection as exit only. However, more beams pass through other critical organs superior to the patient’s body, especially in spine cases where the lesions are located in the posterior-midline regions. Limited studies have been done to determine whether a restriction on the beam entrance for the patient’s arms has significant dosimetric implications for Cyberknife spine treatments. In this study, the plan quality metrics, dose falloff metrics, and dose-volume constraints were compared for Cyberknife SBRT spine cases with and without beams entering through the arms. Material/Methods: Twenty clinical spine cases were computed by setting the beam intersection of the patient’s arms as exit only ( Plan without_arm ). Another plan was then generated using the same cost functions but allowing beam intersection for the arms ( Plan with_arm ). The dosimetric difference was investigated.