Positron emission tomography (PET) in endocrine tumours

Abstract

Positron emission tomography (PET) has many clinical applications in oncology, neurology and cardiology.
PET is widely available in developed countries, and has also become available in a number of middle-income
countries, including South Africa. Commonly used PET radionuclides include fluorine-18, carbon-11, nitrogen-
13 and oxygen-15, which are commonly found in organic chemistry and biochemistry. Undoubtedly the
most important radiopharmaceutical used in PET scanning at present is [F-18]-FDG, which accumulates in
many tumour cells. FDG PET imaging has some specific uses in the evaluation of patients with endocrine
tumours. These include the detection of recurrent differentiated thyroid carcinoma in patients with a rising
thyroglobulin level and negative iodine scan, and cases of recurrent medullary thyroid carcinoma with
rising calcitonin levels. In parathyroid adenoma, FDG PET appears useful in cases where conventional
nuclear medicine imaging is negative. For adrenal masses, FDG PET appears to be a highly accurate tool
to distinguish benign from malignant lesions. The role of FDG PET in phaeochromocytomas, carcinoids and
endocrine pancreatic tumours is probably limited to those that are less well differentiated and metabolically
active. However, a future role for PET imaging in the detection of endocrine tumours, using more specific
substrates, appears very promising.

Journal of Endocrinology, Metabolism and Diabetes of South Africa Vol. 12 (1) 2007: pp. 18-23