What is a standardized uptake value (SUV)?
An SUV is a quantitative measure of PET radiotracer uptake in a tissue of interest and is a unitless value. It is calculated as the ratio of tissue radiotracer activity concentration (i.e., accumulated radiotracer dose in a tissue of interest/volume of the tissue of interest) compared to whole body radiotracer activity concentration (i.e., injected radiotracer dose/body weight [where one assumes that 1 g of body weight = 1 ml volume]). If the distribution of an injected radiotracer were uniform throughout the body, then the SUV would be measured as 1 everywhere. Maximum SUV (SUVmax) is the SUV of the hottest voxel within a lesion. Mean SUV (SUVmean) is the average of the SUVs of all voxels within a lesion. Peak SUV (SUVpeak) is the average of the SUVs of a subset of voxels centered about the hottest voxel within a lesion.