Purpose: To investigate the dose to Cardiac Implantable Electronic Devices (CIEDs) for patients receivingproton beam therapy (PBT). We also characterized major factors contributing to delivered dose to the CIEDin PBT.
Methods: 118 adult patients with the CIED who received PBT- either pencil beam scanning or doublescattering- for brain, Head&Neck, thorax, abdomen, pelvis had their treatment plans and deliveryinformation retrospectively analyzed. Eclipse treatment planning system (TPS) was utilized for protonplanning in this study. Patients without the CIED included in their simulation computed tomography scanwere excluded from studies investigating the distance of the CIED from 50% and 5% isodose lines.
Results: Patient information including age, gender, anatomical site treated, OSLD dose, TPS estimateddose to the CIED, proton beam delivery technique, and fractionation scheme information is tabulated. Outdata show that the CIEDs receive negligible to no dose when the device is at medium/significant distancefrom the treatment area, with its relative location to the treatment volume being the most influential factor for evaluating the dose (both estimated and measured).
Conclusion: For PBT, OSLD and TPS assessed dose to the CIEDs does not have a level of accuracy to draw any significant conclusions. It is generally seen that planning an appropriate treatment with effortstaken to avoid the CIEDs will result in doses that do not exceed or approach the 2 Gy limit. Thus, it is our proposal that patients with a CIED receiving proton therapy be managed in proportion to their dependence on their cardiac device and in line with recommendations from TG-203.