Optimizing Workflow for Cone Beam Computed Tomography-Based Online Adaptive Radiation Therapy Toward Reduced Physician Involvement.

PURPOSE: To evaluate the impact of an optimized online adaptive radiation therapy workflow on physician involvement.

METHODS AND MATERIALS: Data from a prospective phase 2 trial involving 34 prostate cancer patients treated with cone beam computed tomography (CBCT)-based online adaptive radiation therapy (62 Gy in 20 fractions) were analyzed. Manual interventions were required for 2 steps in the workflow: radiation therapy technologist review and adjustment of automatically segmented organs, guiding target segmentation, so-called "influencer," while physicians reviewed and refined the targets. Three different workflows were compared: 2-influencer (rectum and bladder), 3-influencer (+prostate), and 5-influencer (+seminal vesicles and bowel). Time for workflow steps, extent of manual corrections, and target volume changes were compared.

RESULTS

A total of 613 fractions were analyzed. The 5-influencer workflow reduced manual target corrections to 11% of fractions compared with 51% for the 3-influencer workflow and 61% for the 2-influencer workflow (P < .001). Median session duration across workflows was 24.0 minutes (IQR, 22.0-28.0). Median target review times were shortest with the 5-influencer workflow at 2.5 minutes compared with 5.0 minutes for the 3-influencer workflow (P < .001) and 5.6 minutes for the 2-influencer workflow (P = .002). Most patients (84%) found the treatment time well tolerable.

CONCLUSIONS

This study of prostate cancer patients suggests that optimized workflow reduces the need for physician involvement in online CBCT guided adaptive radiation therapy. Optimized workflows may facilitate a more radiation therapy technologist-driven approach similar to standard image guided radiation therapy. Further studies in other cancers, also focusing on clinical endpoints, are needed to further improve CBCT guided online adaptive radiation therapy.