Partial metabolic response to CRT. 2A: Pre-CRT study - Intense rectal FDG uptake. 2B: Pre-CRT study - axial PET-CT images showing hypermetabolic rectal mass. 2C: Post-CRT study - Tumour volume is reduced but considerable tumour uptake is still present. 2D: Axial PET-CT images showing rectal mass in CT images with FDG uptake in PET images.