An Institutional Experience With Motion Management And Proposed Decision-Making Pathways For Igrt

IGRT and motion management techniques of DIBH, respiratory gating, and abdominal compression have been widely used to reduce respiratory motion, decrease target volumes, and reduce dose to organs at risk. Utilization of multiple motion management techniques at time of CT simulation allows for selection of a technique that achieves ideal motion management, but can result in increased number of scans, prolonged simulation times, and patient discomfort. The purpose of this study is to assess a single institution’s experience with motion management and to propose pre-specified decision making pathways to increase efficiency at time of CT simulation. At our institution we introduced pneumatic abdominal compression belt (AC) in 2018. DIBH and respiratory gating technology were already available. At time of introduction, we performed multiple motion management techniques at time of simulation. This allowed for physician and physicist review, comparison, and selection of the technique that provided ideal motion management and OAR displacement. Such simulations included 4d CT, AC, DIBH, and IV contrast scans with real time motion assessments. This approach resulted in increased scan numbers, prolonged CT simulation times (∼2hrs), patient discomfort, and prolonged physician and physicist engagement. Using literature review and institutional experience, we propose that a pre-specified decision making pathway can be developed to increase efficiency while achieving optimal motion management. We stratify decision making by 5 common disease sites that require motion management: upper thoracic, lower thoracic, liver, post-operative peripancreatic, and intact pancreas. For each site we developed a decision making pathway with the primary goal of achieving optimal motion management and secondary goals of reducing number of scans and simulation length and improving quality assurance (Figures 1-5). For all cases where AC is considered, we first perform a 10 minute trial of AC to assess patient tolerance. Standardized descriptive nomenclature for each scan has also been introduced to improve quality assurance and scan selection at time of motion assessment, contouring, and planning. At our institution we have implement pre-specified decision making pathways for motion management at each pertinent disease site. This process has facilitated a more efficient CT simulation process with decreased number of scans, short simulation time (1 hr), and improved patient comfort.