ALARA.

We’ve seen several studies identifying several substructures in the heart that are associated with worse survival or more cardiac events when they receive a higher dose. This study used data from the prospective PET-Plan trial to perform a voxel-wise image based analysis of cardiac dose in patients receiving definitive radiation for NSCLC. The voxel-wise analysis doesn’t require contouring specific substructures, so it localizes risk across the entire heart volume. The cardiac region where differences in dose had the greatest association with survival was focused in the base of the heart near the origin of the LAD and the AV node. Median dose to this area was 33.5Gy, and survival was significantly higher among those with a lower dose. An anatomic sidenote is that these authors also hypothesize that radiation to the cardiac conduction system (such as the nearby SA node identified in another recent study) may contribute to mortality risk. | Craddock, J Thorac Oncol 2022