Internal target volume uncertainty in adrenal stereotactic body radiotherapy: implications of respiratory motion and the value of combined 3DCT–4DCT delineation

Background

Respiratory-induced motion introduces geometric uncertainty in adrenal stereotactic body radiotherapy (SBRT), but its magnitude and impact on internal target volume (ITV) delineation remain poorly characterized. This study quantified adrenal tumor motion, evaluated ITV delineation strategies, and assessed combined approaches to minimize uncertainty.