Increased Gallium-68 DOTATOC Uptake in Normal Thyroid Glands

Abstract

Increased Ga-68 DOTATOC uptake for normal and goitrous and/or nodular thyroids has previously been reported for a small number of patients. The aim of this study was to reevaluate these preliminary findings with larger patient numbers and to determine possible variables, which might influence the quantification of Ga-68 DOTATOC uptake in normal and pathologic thyroid tissues. Ga-68 DOTATOC PET scans of 165 patients classified for various thyroid pathologies were analyzed by the so-called region of interest technique for Ga-68 DOTATOC uptake and the patient's history, thyroid ultrasound, TSH, and anti-TPO antibodies. Thyroid glands without any pathology showed a clearly detectable uptake of Ga-68 DOTATOC with a large variability and significantly higher target to background ratios for men as compared to women. In 8 cases of normal thyroids with an increased uptake, follow-up examinations after 6-14 months did not show any thyroid pathology. An increased DOTATOC uptake (target to background ratio >3.4) was found in hot nodules, disseminated thyroid autonomy, and in most cases (5 of 8) of active Hashimoto's disease. In Ga-68 DOTATOC PET, normal thyroid glands show a clearly detectable radiotracer uptake with a large variability and significantly higher target to background ratios in male patients. All patients with thyroid autonomy and most patients with active Hashimoto's disease have an increased thyroid DOTATOC uptake.