TITLE: Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography in Thyroid Cancer: Results of a Multicentre Study.

REF: Grunwald F, Kalicke T, et al: Eur J Nucl Med 1999; 26 (December): 1547-1552 http://www.ncbi.nlm.nih.gov:80/entr...5&dopt=Abstract

STUDY TYPE: Retrospective review of 222 patients with differentiated thyroid carcinoma.

FINDINGS: FDG PET findings were compared with I-131, Tc-99m MIBI, and Thallium-201 scintigraphy. PET scans were performed after thyroidectomy and I-131 treatment. The FDG PET scans were performed both under thyroid hormone therapy (46/222 pts) or after hormone withdrawal (141/222). In 35 cases, TSH values at time of PET were not available. In all cases, I-131 whole body scintigraphy was performed after thyroid hormone withdrawal. Sensitivity of PET was 75% overall, and 85% for the group with a negative I-131 scan. Specificity of PET was 90%. Sensitivity of the I-131 scan was 50% with a specificity of 99%. Sensitivity and specificity of MIBI / Thallium was 53% and 92% respectively. When FDG PET was combined with I-131, tumor tissue was missed in only 7%.

CONCLUSION: FDG PET is more sensitive than I-131 in detecting suspected recurrence and / or metastases. It is especially useful in those with elevated thyroglobulin values and a negative or equivocal I-131 whole body scan.