Diagnostic CT-Based Palliative Radiotherapy Using kV Image Verification: A Prospective Feasibility Study

Patients receiving palliative radiotherapy (PRT) often experience substantial symptom burden and may face challenges attending multiple hospital visits. Planning treatment using an existing diagnostic computed tomography (dCT) scan instead of a dedicated computed tomography (CT) simulation may improve access to timely care. This prospective feasibility study evaluated a dCT-based planning workflow using kilovoltage (kV) image verification for patients with bone metastases, with potential applicability to resource-limited settings. Ten patients receiving conventional PRT (8 Gy in 1 fraction or 20 Gy in 5 fractions) with an eligible dCT acquired within 28 days were enrolled. As part of this feasibility study, all patients also underwent standard CT simulation, which served as the dosimetric comparator and fallback treatment pathway. Radiotherapy plans generated on dCT and CT simulation scans were compared for dosimetric quality, while treatment deliverability, patient satisfaction, and estimated carbon emissions were assessed. Seven of ten patients were successfully treated using the dCT workflow. The three remaining patients were transitioned to standard CT simulation treatments due to an uncorrectable dCT image rotation in the planning software (n = 1), scheduling constraints (n = 1), and a larger-than-anticipated difference in patient separation on the treatment unit (n = 1). Target coverage and organ-at-risk doses were comparable between dCT and CT simulation plans, satisfaction among dCT-treated patients was high, and potential avoidance of CT simulation was estimated to reduce carbon emissions by approximately 10 kg carbon dioxide equivalent (CO₂e) per patient. These findings demonstrate that dCT-based planning with kV image verification is feasible, provides dosimetry comparable to conventional CT simulation, and warrants further evaluation as a strategy to improve access to timely PRT while reducing healthcare resource use and environmental impact.