title: Intra-patient reproducibility of myocardial SPECT imaging with 201Tl.
abstract: BACKGROUND
  To define the physical and clinical reproducibility of (201)Tl myocardial perfusion SPECT (MPS), this study assesses the variation between two repeated rest (201)Tl MPS with repositioning only, with a two-hour time interval and with phantom measurements as a reference.
  
  
  METHODS
  Three anthropomorphic thorax phantoms were filled with (201)Tl. For each phantom five repeated (201)Tl MPS were obtained. In addition, in 20 patients repeated (201)Tl rest-MPS and in 26 patients early and delayed (201)Tl rest-MPS were performed. Quantitative analysis was done using MunichHeart. Statistical methods were used to calculate variability. Visual analysis was performed by 2 independent observers.
  
  
  RESULTS
  The average variation between repeated phantom MPS was 0.5% (95% confidence interval (CI): -0.4% to 1.4%). For patient scans this was -5.0% (95% CI: -2.5% to -7.5%) and between early and delayed (201)Tl MPS -15.5% (95% CI: -11.7% to -19.3%). Visual assessment revealed no clinical significant differences between rest (201)Tl and repeated or delayed (201)Tl MPS.
  
  
  CONCLUSIONS
  Repositioning in phantom (201)Tl MPS does not cause significant variation. Repeated (201)Tl MPS in patients shows 5.0% decrease of (201)Tl in 30 minutes, which increases to 15% during a two-hour time interval without quantitative or visual regional differences. This decrease indicates a time-related washout of (201)Tl, but does not change clinical diagnosis.
authors.affiliation: Department of Nuclear Medicine, St. Antonius Hospital, Koekoekslaan 1, Postbus 2500, 3430 EM, Nieuwegein, The Netherlands. barbrabackus@hotmail.com
authors.forename: Barbra E
authors.initials: BE
authors.lastname: Backus
authors.forename: Frederik A
authors.initials: FA
authors.lastname: Verburg
authors.forename: R Leo
authors.initials: RL
authors.lastname: Romijn
authors.forename: Mark W
authors.initials: MW
authors.lastname: Konijnenberg
authors.forename: Freek J
authors.initials: FJ
authors.lastname: Beekman
authors.forename: J Fred
authors.initials: JF
authors.lastname: Verzijlbergen
mesh_terms: D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013793:Thallium; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; C027549:thallium chloride; D013793:Thallium