Another explanation is that local radiation effects such as inflammation are not reflected in plasma concentrations of FAP, as has been shown by our group before in cardiovascular disease: Circulating FAP concentrations in patients with acute myocardial infarction or aortic stenosis were independent of localized FAP expression in the heart as analyzed by whole body nuclear imaging using positron emission tomography [10]. The gene discussed is FAP; the disease is myocardial infarction.