Room: ePoster Forums
Purpose: Patients with cervical cancer treated with CDRâ€‘CASâ€‘IMAT using conventional Linac Varian 23EX can get equivalent or superior dose distribution compared to those treated with IMRT, while which will increased lowâ€‘dose irradiated area. The purpose of this study was to investigate the feasibility of using multi-criteria dose plan optimization (MCO) for CDRâ€‘CASâ€‘IMAT MCO-based plan futher sparing of organs at risk.
Methods: Twenty patients with cervical cancer previously treated with CDRâ€‘CASâ€‘IMAT were retreated using multi-criteria optimization CDRâ€‘CASâ€‘IMAT-MCO plan on Monaco (v5.1.0) TPS. Minimum acceptable target coverage with physician-defined organsparing priorities. Maximum bowel sparing without losing target coverage (if needed at the expense of the bladder). Maximum bladder sparing without losing target coverage (if needed at the expense of the bowel).The quality of the CDRâ€‘CASâ€‘IMAT-MCO plans was compared to the quality of the non-MCO VMAT plans, and the ability of the MCO module to selectively spare OARs (bladder or bowel) with CDRâ€‘CASâ€‘IMAT-MCO was evaluated.
Results: All plans satisfies constraints for target coverage (CTV: V95%=100% and PTV: V98%â‰¥95%).Non-MCO plans had higher Conformity Index (CI) compared to CDRâ€‘CASâ€‘IMAT-MCO(0.75 Vs. 0.71). CDRâ€‘CASâ€‘IMAT-MCO plans had smaller hotspots in elective volumes, but higher dose volumes to bowel. Time spent on optimization was shorter for Non-MCO due to considerable increase in the calculation and conversion time compared to CDRâ€‘CASâ€‘IMAT-MCO (16.4 Â± 3.5 min vs. 18.6 Â± 2.2 min).
Conclusion: This study demonstrates that preference-informed dose planning with CDRâ€‘CASâ€‘IMAT-MCO is indeed feasible, selective sparing of OARs in CDRâ€‘CASâ€‘IMAT-MCO can significantly reduced options for dose redistribution. Further investigations will be undertaken to review any clinical benefit of this improved planned dosimetry.