Recent reports confirmed increased SSTR expression in the thyroid in some cases of Graves disease and hot nodules. It is still not known, whether SSTRs can frequently be found in other thyroid pathologies or normal thyroid glands. Therefore, we performed a systematic analysis of Ga-68-Dotatoc PET Scans for their thyroid image.
Eighty-three consecutive patients undergoing Ga-68-Dotatoc PET were analysed for their relative thyroid uptake by ROI technique for each thyroid lobe separately. Using a 1 cm thick coronal slice including highest thyroidal uptake, target-background-ratios (TBRs) were calculated. TSH, fT3, fT4 and anti-TPO were measured, the thyroid specific history was recorded and thyroid ultrasound was performed. 99mTc scintigraphy was used in cases of a TSH<0.4 mU/l or sonographically detected nodes.
Thyroid lobes without pathology (n=62) show a significantly higher uptake as compared to the same region after lobe excision (n=24) (P<0.001). Compared to normal thyroid lobes, goitrous lobes (n=22) in mean show a slightly increased uptake (P=0.025). Markedly increased uptake was found in thyroid lobes with hot nodules (n=2, TBR=9.7 and 6.4) and in disseminated autonomy.
PET scans showed a high uptake in 3 of 5 patients with active Hashimotos disease.
Results confirm a high SSTR density in hot nodules and disseminated autonomy. However, normal as well as thyroids with non-toxic nodules and goiters show a clearly detectable SSTR expression with large variability. Intense tracer uptake was found in only few cases of structurally and functionally normal thyroid lobes. Like Graves disease, some cases of active Hashimotos disease show a high SSTR density.
03 - 07 May 2008
European Society of Endocrinology