An In Silico study of a One-Day One-Machine Workflow for Definitive Radiotherapy Cases on a Novel Simulation and Treatment Platform

Abstract

The workflow in Radiotherapy (RT) has largely unchanged for the past three decades, despite increasing evidence suggesting that delayed access to RT, including the wait time between consultation, simulation, and treatment appointments, can negatively impact clinical outcomes. In this pilot study, we present preliminary results of an in silico study that demonstrate the feasibility of a novel RT platform, which integrates simulation into the treatment process and enables patients to receive immediate RT after their initial RT consultation. A prospective clinical study has been approved to assess the capabilities of a novel RT platform with a high quality CBCT system for imaging guidance as well as planning. This new platform enables a novel clinical workflow that allows clinicians to review contours and plans created on diagnostic CT images prior to the initial RT consultation and allow them to approve new plans adapted on the actual simulation dataset acquired on the first treatment fraction. Four patients receiving standard of care RT (three abdomen and one thorax) consented for this study and underwent additional experimental CBCT simulation on the new platform in addition to their standard CT simulation. The CBCT simulation was taken in two setups: with a specific mold on a flat couch and without a mold on a curved couch. To demonstrate the equivalence of the new workflow to the current standard of care, the plan created on the most recent diagnostic CT images was compared to the plans adapted on the experimental simulation images and the standard CT simulation images, using a knowledge-based model. Contours were propagated from approved datasets to the new datasets through deformable image registration. All experimental simulations were completed between 14 and 21 minutes with the assistance of two therapists. The contouring, editing, and replanning process took less than one hour in all cases, in line with our experience and peer-reviewed literature. Despite notable anatomical changes observed, the dose-volume histograms (DVH) were consistent, as shown in Table 1. The novel workflow presented herein was feasible and demonstrates that the integration of simulation with image-guided RT on one single platform may unlock the potential of accelerating the RT workflow and reducing the wait time for treatment from weeks to hours.