Effects of image cropping on DSC. Box plots of DSC obtained using rigid and non-rigid registration strategies and various levels of image cropping. DSC values were obtained using (a) PET, (b) CT or (c) both (CTPET). Reference shows the largest overlap in volume that could be achieved for VOI delineated on both scans separately. The mean is illustrated by a square, outliers by dots, and minimum and maximum values by crosses.