title: Positron emission tomography for the detection of metastases of differentiated thyroid carcinoma.
abstract: OBJECTIVE
  To show the value of positron emission tomography (PET) with 18-F-fluorodeoxyglucose (18-FDG) for the detection of metastases of differentiated thyroid carcinoma in selected patients.
  
  
  METHODS
  There were four patients, who had undergone total thyroidectomy for papillary (two) or follicular thyroid carcinoma (two). All patients had subsequent treatment with (131)iodine. Three patients had an increasing serum concentration of thyroglobulin, one patient had antibodies against thyroglobulin. A diagnostic (131)iodine scintigraphy was negative in two patients, and uncertain in two patients. Positron emission tomography was performed about 45 min after administration of 10 mCi 18-F-fluorodeoxyglucose. In three patients PET showed uptake in the cervical region, caused by lymph node metastases in two (confirmed by neck dissection) and recurrent tumor on the trachea in one patient (confirmed by surgery). In the fourth patient uptake of 18-FDG was seen in the neck and in both lungs. This led to discontinuation of treatment with (131)iodine because the lung metastases did not accumulate (131)iodine.
  
  
  CONCLUSIONS
  In selected patients with differentiated thyroid carcinoma with an increasing serum concentration of thyroglobulin, PET is an important diagnostic option when scintigraphy with (131)iodine is negative or uncertain. In the four presented case histories, the results of PET led to a therapeutic decision: surgery in three patients and discontinuation of (131)iodine in one patient. The development of guidelines for the use of PET in the diagnosis of recurrent thyroid cancer is discussed.
authors.affiliation: Department of Endocrinology, Academic Hospital Vrije Universiteit, P. O. Box 7057, 1007 MB Amsterdam, The Netherlands. p.lips@azvu.nl
authors.forename: P
authors.initials: P
authors.lastname: Lips
authors.forename: E F
authors.initials: EF
authors.lastname: Comans
authors.forename: O S
authors.initials: OS
authors.lastname: Hoekstra
authors.forename: E
authors.initials: E
authors.lastname: van der Poest Clement
authors.forename: J C
authors.initials: JC
authors.lastname: van Mourik
authors.forename: G J
authors.initials: GJ
authors.lastname: Teule
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000097:blood / Q000000981:diagnostic imaging* / Q000556:secondary* / Q000601:surgery; D000328:Adult; D000359:Aftercare / Q000379:methods; D000368:Aged; D002291:Carcinoma, Papillary / Q000097:blood / Q000000981:diagnostic imaging* / Q000556:secondary* / Q000601:surgery; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D017410:Practice Guidelines as Topic; D013954:Thyroglobulin / Q000097:blood; D013964:Thyroid Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000556:secondary* / Q000601:surgery; D013965:Thyroidectomy; D014055:Tomography, Emission-Computed / Q000379:methods*
chemical_list: D007457:Iodine Radioisotopes; D019788:Fluorodeoxyglucose F18; D013954:Thyroglobulin