A Radiation Therapy Contouring Atlas for Cardiac Conduction Node Delineation.

Abstract

The heart is a complex organ at risk. Currently, radiation therapy cardiac delineation atlases do not include conduction system substructures, which exposure may clinically translate into arrhythmia and conduction disorders. We present a method to reproducibly delineate conduction nodes on noncontrast simulation computed tomography scans. Localization and dimensioning of the sinoatrial and atrioventricular nodes volumes on noncontrast simulation computed tomography scans were proposed based on radio-anatomic and histologic considerations and agreed upon by a multidisciplinary staff. The proposed atlas enables the dosimetric evaluation of the sinoatrial and atrioventricular nodes exposure, and both contours correspond to 2-cm diameter spheres. This delineation atlas should facilitate the delineation of cardiac conduction nodes in clinical research and daily practice.