2680 - Clinical Feasibility and Prospective Developments of Fan Beam CT-Guided All-in-One Emergency Radiotherapy

Purpose/Objective(s): Conventional radiotherapy workflows, with segmented steps and prolonged waiting times, are particularly suboptimal for managing oncologic emergencies. This prospective study assesses the efficiency of an all-in-one (AIO) emergency radiotherapy platform in reducing time to treatment initiation while maintaining therapeutic quality.

Materials/Methods: Ten patients with metastatic spinal cord compression (MSCC), primarily originating from breast and lung cancer, underwent AIO emergency radiotherapy at a single institution between April 17 and December 25, 2024. MSCC patients who met the criteria for emergency radiotherapy and provided informed consent were treated using an integrated system with Fan Beam CT (FBCT) and artificial intelligence (AI) - driven contouring and planning platforms (Radiotherapy equipment: uRT-linac506c with uTPS). The workflow required collaboration among radiation oncologists, medical physicists, and radiation therapists. It encompassed patient immobilization, CT simulation, and AI-assisted delineation of organ-at-risk (OAR) and target volumes. Target volumes were defined as follows: Gross Tumor Volume (GTV) included all CT/MRI-visible tumors. Clinical Target Volume (CTV) was contoured by expanding the GTV with an appropriate margin, encompassing the radiographically involved vertebral body and adjacent osseous structures. Planning Gross Tumor Volume (PGTV) and Planning Target Volume (PTV) were generated using 5 mm isotropic expansions from the GTV and CTV respectively, with manual contour modifications to maintain spinal cord dose constraints. The AI-assisted Volumetric Modulated Arc Therapy with Simultaneous Integrated Boost (VMAT-SIB) plan was generated (Prescribed dose: PTV: 30 Gy/10fx; PGTV: 48 Gy/12fx). The VMAT-SIB plan aimed to improve local control of MSCC while maintaining spinal cord dose constraints (Dmax = 45 Gy). The plan was manually evaluated, verified with final FBCT, and delivered. All procedures were performed on an integrated platform, with treatment duration documented.

Results: All 10 patients successfully completed the entire treatment in a single, streamlined workflow. The mean time from patient immobilization to treatment completion was 45.14 min (34.41 - 52.25 min), with no significant post-treatment discomfort. One-month post-radiotherapy, 70% (7/10) of patients reported pain relief according to the NRS, and 60% (6/10) showed at least one grade improvement on the Frankel scale. Compared to conventional radiotherapy with a one-week wait, AIO shortened treatment delays and relieved pain of patients efficiently.

Conclusion: The FBCT-guided AIO emergency radiotherapy model showed high clinical feasibility and broad application potential. Future studies should expand the sample size and validate this model in diverse oncologic emergencies, promoting precision medicine and patient-centered care while redefining oncology emergency management. ClinicalTrials.gov: NCT06608108.