Do you contour the renal hilum/vascular trunk and renal cortex as separate structures when doing SBRT near the kidney?  

This is an excellent question in radiotherapy dosimetry that has long been overlooked. In classical radiobiology, a typical organ-at-risk (OAR) can be considered as exhibiting either parallel or series patterns based on the spatial arrangement of its functional subunits (FSUs) (Withers HR et al. IJR...