title: Low-activity 124I-PET/low-dose CT versus 99mTc-pertechnetate planar scintigraphy or 99mTc-pertechnetate single-photon emission computed tomography of the thyroid: a pilot comparison.
abstract: OBJECTIVE
  The standard thyroid functional imaging method, 99mTc-pertechnetate (99mTc-PT) planar scintigraphy, has technical drawbacks decreasing its sensitivity in detecting nodules or anatomical pathology. 124I-PET, lacking these disadvantages and allowing simultaneous CT, may have greater sensitivity for these purposes. We performed a blinded pilot comparison of 124I-PET(/CT) versus 99mTc-PT planar scintigraphy or its cross-sectional enhancement, 99mTc-PT single-photon emission CT (SPECT), in characterizing the thyroid gland with benign disease.
  
  
  METHODS
  Twenty-one consecutive adults with goiter underwent low-activity (1 MBq/0.027 mCi) 124I-PET/low-dose (30 mAs) CT, 99mTc-PT planar scintigraphy, and 99mTc-PT-SPECT. Endpoints included the numbers of “hot spots” with/without central photopenia and “cold spots” detected, the proportion of these lesions with morphological correlates, the mean volume and diameter of visualized nodules, and the number of cases of lobus pyramidalis or retrosternal thyroid tissue identified.
  
  
  RESULTS
  124I-PET detected significantly more “hot spots” with/without central photopenia (P < 0.001), significantly more nodules (P < 0.001), and more “cold spots” than did 99mTc-PT planar scintigraphy or 99mTc-PT-SPECT, including all lesions seen on the 99mTc-PT modalities. Ultrasonographic correlates were found for all nodules visualized on all 3 modalities and 92.5% of nodules seen only on 124I-PET. Nodules discernible only on 124I-PET had significantly smaller mean volume or diameter (P < 0.001) than did those visualized on 99mTc-PT planar scintigraphy or 99mTc-PT-SPECT. 124I-PET(/CT) identified significantly more patients with a lobus pyramidalis (P < 0.001) or retrosternal thyroid tissue (P < 0.05).
  
  
  CONCLUSIONS
  124I-PET(/CT) may provide superior imaging of benign thyroid disease compared to planar or cross-sectional 99mTc-PT scintigraphy.
authors.affiliation: From the *Clinic of Nuclear Medicine, Jena University Hospital, and †BioControl Jena, Data Analysis and Process Optimization, Jena, Germany; and ‡Spencer-Fontayne Corporation, Jersey City, NJ.
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Darr
authors.forename: Thomas
authors.initials: T
authors.lastname: Opfermann
authors.forename: Tobias
authors.initials: T
authors.lastname: Niksch
authors.forename: Dominik
authors.initials: D
authors.lastname: Driesch
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Marlowe
authors.forename: Martin
authors.initials: M
authors.lastname: Freesmeyer
mesh_terms: D000328:Adult; D000368:Aged; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D013670:Sodium Pertechnetate Tc 99m; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000473:pathology; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D007457:Iodine Radioisotopes; D013670:Sodium Pertechnetate Tc 99m