A Study of Online Adaptive Planning Workflow for Pancreatic Cancer Using Adapt LTE
Abstract
Purpose
This study aimed to evaluate Adapt LTE, a retrospective evaluation tool by Accuray to compare past helical treatment plans against original therapy goals.
Methods
Five pancreatic cancer patients treated on Radixact machines, all with large anatomy changes, were retrospectively studied. Using Adapt LTE, contours from planning images were deformed and propagated to the merged daily CT images (5 fractions each). The deformed pancreas and duodenum contours were compared against expert-defined ground truth manual delineations and evaluated using mean distance to agreement (MDA) and Dice similarity coefficients. Dose from the daily delivery with IGRT only, the adaptive plan with re-optimization, and the original reference plan were evaluated by comparison to planning goals (PG). The time needed at each step in Adapt LTE, including contour propagation, daily dose calculation, adaptive optimization and final dose calculation were recorded.
Results
Adapt LTE-generated deformed pancreas and duodenum contours satisfied acceptance criteria, achieving average MDA values of 1.76 mm and 1.98 mm and Dice scores of 0.80 and 0.79, respectively. Dosimetric analysis showed that none of the daily plans treated with IGRT alone met PTV acceptance criteria, with significant deviations from the PG. The duodenal D0.03cc exceeded the PG by 1.23%. In contrast, adaptive planning improved target coverage (>95% of PTV) and kept duodenal D0.03cc within tolerance. The Adapt LTE workflow required an average processing time of ~15 minutes, of which approximately 65% was attributable to adaptive optimization. The total treatment time, including patient setup, IGRT, adaptation and delivery, is expected to be completed within 30 minutes.
Conclusion
Adapt LTE provided fast and accurate contour propagation, improved target coverage, and OAR sparing with adaptive optimization. The adaptive workflow is efficient and clinically feasible. Adapt LTE can help clinicians analyze outcomes, refine decision-making and train more effectively in adaptive techniques.