Research Article

Effects of ROI Placement on PET-Based Assessment of Tumor Response to Therapy

Figure 1

Change in the distribution of FDG uptake during treatment. The PET/CT images of Pre-Tx (a) and Intra-Tx (b) are of a patient with a base of tongue primary tumour. Two circular ROIs of 15 mm diameter are centered at the maximum uptake points on both Pre-Tx (green) and Intra-Tx (red) images denoted by “M.” An additional 15 mm diameter circular ROI is placed on the Intra-TX image (blue) in a position judged to correspond to the same anatomical location as the ROI as in the Pre-Tx. The FDG uptake profiles along the black lines connecting the two Intra-Tx ROIs are shown in Figure 2.