Fig. 25. 10 Medullary carcinoma of the thyroid (MCT) imaged with 99mTc dimercaptosuccinic acid (DMSA-V). These images were taken four hours after intravenous injection of 99mTc DMSA-V. In (a) the head and neck have focally increased uptake in the region of the thyroid to the left of the midline. Note normal thyroid tissue is not shown. Image of the anterior abdomen (b); in the centre of the abdomen a small area of increased uptake is seen which was subsequently shown to be a metastasis of the MCT. 99mTc DMSA-V is taken up by several other tumours and by some types of amyloid. Its most consistent uptake is in MCT and it is used to demonstrate primary and recurrent disease. MCT does not take up radioiodine or 99mTc pertechnetate and appears as a ΓÇÿcoldΓÇÖ area on a conventional thyroid scan.
