title: Better yield of (18)fluorodeoxyglucose-positron emission tomography in patients with metastatic differentiated thyroid carcinoma during thyrotropin stimulation.
abstract: To determine whether (18)fluorodeoxyglucose-positron emission tomography (FDG-PET) for the detection of recurrences or metastases of differentiated thyroid carcinoma should be performed during thyrotropin (TSH) suppression or TSH stimulation, eight patients were studied sequentially. After the second FDG-PET scan, a therapeutic (131)I dose was administered with posttherapy scans obtained 10 days later. Both FDG-PET scans were compared with each other and with the (131)I posttherapy whole body scans by two independent observers. Findings were verified using other imaging modalities or biopsies. Median TSH was 0.04 mU/L during TSH suppression and 64 mU/L during TSH stimulation. The FDG-PET scans during TSH suppression showed abnormalities in four patients and the FDG-PET scan during TSH stimulation in five patients. One patient was only positive during TSH stimulation. In two other patients the FDG-PET scan during TSH stimulation clearly identified more lesions, and in all positive patients lesion contrast was better during TSH stimulation. In two patients FDG-PET findings during TSH stimulation led to a change in clinical management. Thus, the performance of FDG-PET during TSH stimulation was either superior or equal to FDG-PET during TSH suppression, but never inferior. To detect metastatic or recurrent differentiated thyroid carcinoma FDG-PET should be performed during hypothyroidism, leading to TSH stimulation.
authors.affiliation: Department of Endocrinology, University Hospital Groningen, The Netherlands. K.M.van.Tol@int.azg.nl
authors.forename: Karin M
authors.initials: KM
authors.lastname: van Tol
authors.forename: Pieter L
authors.initials: PL
authors.lastname: Jager
authors.forename: D Albertus
authors.initials: DA
authors.lastname: Piers
authors.forename: Jan
authors.initials: J
authors.lastname: Pruim
authors.forename: Elisabeth G E
authors.initials: EG
authors.lastname: de Vries
authors.forename: Robin P F
authors.initials: RP
authors.lastname: Dullaart
authors.forename: Thera P
authors.initials: TP
authors.lastname: Links
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013268:Stimulation, Chemical; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D013972:Thyrotropin / Q000097:blood / Q000494:pharmacology*; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed; D014915:Whole-Body Counting
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D013972:Thyrotropin