title: 99mTc-depreotide scintigraphy versus 18F-FDG-PET in the diagnosis of radioiodine-negative thyroid cancer.
abstract: BACKGROUND
  Papillary and follicular thyroid cancer were found recently to express somatostatin receptors (SSTRs). (99m)Tc-depreotide binds with high affinity to SSTRs 2, 3, and 5.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the feasibility of applying (99m)Tc-depreotide scintigraphy to search for radioiodine-negative thyroid cancer; comparison is made to a standard approach using (18)F-fluorodeoxyglucose-positron emission tomography ((18)F-FDG-PET).
  
  
  METHODS
  Ten radioiodine-negative patients with suspicion of recurrent or metastatic thyroid cancer were investigated with (99m)Tc-depreotide scintigraphy and (18)F-FDG-PET, performed with a time interval that ranged from 1-8 wk. Locoregional recurrence and metastases were confirmed by ultrasonography and/or computed tomography, together with cytology or histological examination in selected cases.
  
  
  RESULTS
  True-positive results were obtained in nine patients (90%) with (99m)Tc-depreotide scintigraphy and in seven patients (70%) with (18)F-FDG-PET. (99m)Tc-depreotide scintigraphy gave better results in terms of detection of recurrent or metastatic disease compared with (18)F-FDG-PET in three patients, whereas (18)F-FDG-PET identified metastatic disease that was not seen with (99m)Tc-depreotide in only one patient. (99m)Tc-depreotide scintigraphy portrayed lesions in three patients with negative morphological imaging.
  
  
  CONCLUSIONS
  Results indicate a potential value of (99m)Tc-depreotide scintigraphy for the diagnosis of thyroid cancer in the setting of detectable thyroglobulin and negative radioiodine scan. Furthermore, (99m)Tc-depreotide adds complementary information regarding the SSTR status of lesions, which may be helpful for individual therapy planning in this group of patients, which is hard to manage clinically.
authors.affiliation: University Clinic for Nuclear Medicine, Anichstrasse 35, A-6020 Innsbruck, Austria. rodriguesradischat@hotmail.com
authors.forename: Margarida
authors.initials: M
authors.lastname: Rodrigues
authors.forename: Shuren
authors.initials: S
authors.lastname: Li
authors.forename: Michael
authors.initials: M
authors.lastname: Gabriel
authors.forename: Dirk
authors.initials: D
authors.lastname: Heute
authors.forename: Michaela
authors.initials: M
authors.lastname: Greifeneder
authors.forename: Irene
authors.initials: I
authors.lastname: Virgolini
mesh_terms: D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes / Q000032:analysis; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D049268:Positron-Emission Tomography; D013004:Somatostatin / Q000031:analogs & derivatives*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*
chemical_list: D007457:Iodine Radioisotopes; D015609:Organotechnetium Compounds; D019788:Fluorodeoxyglucose F18; D013004:Somatostatin; C444119:technetium Tc 99m depreotide