[Localization diagnosis of enlarged parathyroid glands: 201Tl-99mTc-subtraction scintigraphy compared with 5-MHz-sonography]

Endocrinological applications in nuclear medicine

Diagnosis and treatment of thyroid diseases have played a major role in Central European Nuclear Medicine. Since 1950, endocrinological nuclear medicine has been one of the strengths of this medical discipline. Not only diagnosis but also conservative treatment with thyroid depressants or hormones is performed by the nuclear medicine specialists. Nuclear medicine also takes part in the diagnosis of other endocrine diseases. The respective procedures include imaging of the adrenal gland (cortex and medulla) as well as of the parathyroid glands. Especially in the latter diseases, imaging was improved through Tc-99m sestamibi scintigraphy. Beyond that, the measurement of bone mineral content contributes to the full spectrum of endocrinological nuclear medicine. The development of In-111 octreotide now plays a limited role in the diagnosis of diseases of the pituitary gland.

Parathyroid imaging by Tc/Tl scintigraphy

Between 1983 and 1988, a total of 224 99mTc/201Tl subtraction parathyroid scintigraphy studies were performed in 214 patients (136 women, 78 men, average age 50, +/- 15 years) with clinical and biochemical signs of hyperparathyroidism. Of the 214 patients, 113 underwent surgical exploration, and 127 benign parathyroid lesions were found, 48 of which were correctly localized by scintigraphy (sensitivity 38%). We detected 30 of 71 adenomas (42%) and 18 of 56 hyperplastic glands (32%). Additionally, the scans localized 2 of 6 parathyroid carcinomas in 5 patients. Overall, 83 parathyroid lesions were missed. There was no significant difference in size between detected and missed lesions. Previous neck surgery (65 of 113 patients) was not a significant detriment to scan sensitivity; but correct detection did depend upon the anatomic site of the lesion: 39% (n = 109) were detected in the typical site, 44% (n = 9) intrathyroidal, and 11% (n = 9) in the anterior and/or superior mediastinum. In conclusion, these results show only limited value for this 99mTc/201Tl subtraction scintigraphy protocol as the initial procedure for localization of abnormal parathyroid tissue prior to surgical exploration.