Presenter(s)
T. Lowe1, K. Grimberg1, R. Hartley1, S. Wong1, S. Roderick1, J. W. Atyeo1, B. Porter1, S. Bergamin1,2, T. N. Eade1,2, and A. Kejda1; 1Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, NSW, Australia, 2Sydney Medical School, University of Sydney, Sydney, NSW, Australia
Purpose/Objective(s):
Simulation-Free Radiation Therapy (SFRT) uses diagnostic computed tomography (dCT) images for treatment planning in palliative radiation therapy, eliminating the need for a dedicated simulation scan. The patient position in a dCT may be inadequate for radiotherapy treatment, which can impact setup reproducibility. Minor positional discrepancies may be corrected by rotating the diagnostic dataset to improve patient alignment prior to planning. This study evaluates whether realigning diagnostic CT datasets using image processing software improves patient position reproducibility and workflow efficiency in a SFRT program. Materials/Methods:
The dCT realignment workflow was applied to 50 prospective SFRT patients prior to treatment and compared with a retrospective cohort of 50 patients treated using standard SFRT protocols. A total of 81 treatment fractions were examined in the prospective cohort and 77 fractions in the retrospective cohort. Image processing software was used to correct dCT datasets by rotating them about the cranio-caudal, anterior-posterior, and left-right axes to ensure appropriate patient positioning prior to treatment planning. Patient position reproducibility was assessed by comparing the magnitude of online rotational couch shifts, while efficiency was evaluated by comparing cone beam CT (CBCT) review time, total treatment time, repeat imaging frequency, and Radiation Oncologist (RO) attendance during image matching between the two cohorts. Statistical significance was assessed using Wilcoxon rank sum tests. Results: Prospective use of realigned diagnostic CT datasets significantly reduced median CBCT review time (4.9 vs 8.7 minutes, p = 0.018) and total treatment time (17 vs 23 minutes, p = 0.006) when compared to the retrospective cohort. Median online rotational couch corrections were significantly lower for roll (0.9° vs 2.5°, p < 0.001), rotation (0.4° vs 1.4°, p < 0.001) and pitch (1.3° vs 1.8°, p < 0.043). Repeat imaging decreased from a median of 1.5 to 1.03 per patient and RO attendance during image matching decreased from six to two instances.
Conclusion: The dCT realignment workflow improved setup reproducibility and reduced treatment time, repeat imaging. These results suggest that routine correction of diagnostic CT datasets prior to treatment planning can be effectively integrated into the SFRT workflow for all patients, conserving valuable time on the treatment couch. This streamlined approach enhances the efficiency and accessibility of simulation-free palliative radiation therapy and supports its broader clinical implementation.
