Fig. 25.22
 Images in a patient with acromegaly using 123I tyr-3-octreotide (somatostatin analogue).
 The planar images are taken at 10–20 minutes after injection: (a) anterior view; (b) left lateral view; (c) right lateral image of the head. There is intense focally increased uptake  in the pituitary region due to the presence of somatostatin receptors on the cells of the tumour, which are labelled. Such patients respond to octreotide, therapeutically, with reduction in circulating growth hormone. Indium (111In) labelled octreotide analogue may also be used for imaging.