Main Session
Sep
28
PQA 03 - Digital Health Innovation and Informatics, Patient Safety & Quality, and Radiation and Cancer Biology
2619 - Same-Day Simulation-Free Radiotherapy Using Diagnostic CT: Feasibility and Dosimetric Validation in a Low-Resource Radiation Oncology Setting
Presenter(s)
Baozhou Sun, PhD, MBA - Baylor College of Medicine, Houston, Tx
B. Sun1, O. Awad1, V. Ugarte1, B. Zhou2, Y. Han1, A. S. Mohamed1, Z. A. Siddiqui1,3, D. A. Hamstra1, and A. N. Hanania4; 1Department of Radiation Oncology, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, 2Radiation Oncology, Baylor College of Medicine, Houston, TX, 3Baylor College of Medicine, Houston, TX, 4Department of Radiation Oncology, Dan. L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX
Purpose/Objective(s):
In low-resource settings, access to radiation therapy (RT) is frequently hindered by limited equipment and staff, high patient volumes, and significant transportation expenses. The traditional RT workflow, requiring a dedicated CT simulation session, often creates a bottleneck that delays palliative care. This study evaluates the feasibility and value of a "simulation-free" (sim-free) workflow -- utilizing diagnostic (dCT) scans for treatment planning. Our hypothesis is that using a sim-free workflow will significantly reduce patient wait time without compromising treatment quality in a low-source setting.Materials/Methods:
We compared a cohort of 12 patients treated via a sim-free workflow for palliative indications against a control group of 30 patients (14 inpatients, 16 outpatients) treated using a conventional simulation workflow over a 3-month period. For the sim-free arm, treatment plans were generated directly from dCTs within the Treatment Planning System (TPS). Geometric and dosimetric validity was verified on the first fraction using cone-beam CT (CBCT), which was converted to a synthetic CT (sCT) in the TPS for deformable registration, dose recalculation, and comparison. Key metrics included time-from-consultation to treatment (T2T), delivery time, and dosimetric concordance between dCT and sCT plans.Results:
The sim-free workflow significantly reduced the median T2T. For outpatients, the median T2T dropped from 537.8 hours (range: 289.7–1516.2) in the conventional arm to just 1.66 hours in the same-day sim-free arm (p < 0.001). For inpatients, the conventional median T2T was 23.9 hours (range: 1.67–143.8). By bypassing the CT simulation suite, the department saved an average of 45 minutes of simulation machine time per patient. Total treatment delivery time for the first fraction remained comparable between the two workflows (26.7 min vs. 30.9 min). Dosimetric analysis showed a mean deviation of 0.13% ± 2.3% in mean dose and 0.30% ± 0.56% in D95 in the PTV coverage between dCT-based plans and sCT verifications, confirming the safety of this approach. Notably, 92% of sim-free patients completed consultation and their first fraction on the same day, reducing costly ambulance transfers between the main hospital and the radiation clinic.Conclusion:
A simulation-free workflow provides substantial value in resource-limited settings by optimizing existing diagnostic imaging for treatment planning. By enabling a "one-stop" model, this workflow significantly reduces treatment delays and mitigates the financial and logistical barriers (e.g., ambulance transport and travel, and limited simulation time slots) that often prevent patients in low-resource environments from receiving timely palliative care.