title: The retention indices of 201Tl-SPECT in brain tumors.
abstract: OBJECTIVE
  The aim of this study was to assess the utility of 201Tl SPECT in the differential diagnosis of intracranial tumors and to determine the relationship between 201Tl uptake and histological types.
  
  
  METHODS
  Thirty-eight patients (19 males and 19 females) with thirty-eight brain tumors were evaluated with 201Tl-SPECT. The early and delayed 201Tl uptake ratio was calculated, and the retention index (RI) was applied as follows; RI = delayed uptake ratio/early uptake ratio.
  
  
  RESULTS
  The RI of malignant tumors was higher (0.72 +/- 0.18) than that of benign tumors (0.50 +/- 0.16) and the difference was statistically significant (p = 0.00045). The difference between high-grade glioma (0.80 +/- 0.15) and metastatic tumors (0.64 +/- 0.19) was statistically significant (p = 0.039).
  
  
  CONCLUSIONS
  201Tl-SPECT may add useful biochemical information and could differentiate malignant brain tumors from benign lesions, but the RI of metastatic tumors varied depending on the organs with the primary lesion and histological types.
authors.affiliation: Department of Radiology, Ehime Central Prefectural Hospital, Japan. hotsuka@clin.med.tokushima-u.ac.jp
authors.forename: Hideki
authors.initials: H
authors.lastname: Otsuka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shinbata
authors.forename: Masashi
authors.initials: M
authors.lastname: Hieda
authors.forename: Kyo
authors.initials: K
authors.lastname: Yamashita
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kitamura
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Senba
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kashihara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tagashira
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000145:classification* / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000378:metabolism; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013793:Thallium / Q000493:pharmacokinetics; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; C027549:thallium chloride; D013793:Thallium