1 Both heart dose and baseline cardiac risk have been associated with cardiac events after high-dose thoracic RT, and studies are now evaluating the impact of radiation dose on sensitive structures, such as the base of the heart.2-4 However, despite advances in our understanding of these issues, cardiac risk assessment during treatment planning for lung cancer has remained largely simplistic, often focusing on dosimetric values (eg, mean heart dose), which are of limited predictive value in...