title: External radioactive reference markers in SPECT imaging of the dopamine system.
abstract: OBJECTIVE
  External radioactive reference markers have been used to localize the canthomeatal (CM) line and correct for head rotation in perfusion brain SPECT. This ensures that regardless of the subject's head position or rotation under the SPECT camera, reconstructed transaxial slices are reoriented parallel to the CM line. This study was undertaken to demonstrate the value of external radioactive reference markers in dopamine SPECT imaging.
  
  
  METHODS
  We compared visual and marker methods of reorienting the transaxial slices between dopamine and perfusion brain SPECT studies, respectively. These consisted of imaging normal controls and patients with Alzheimer's or Parkinson's disease using a triple-head camera. Intra- and interoperator variability of the visual and marker methods of reorientation was determined for both perfusion and dopamine studies.
  
  
  RESULTS
  In both intra- and interoperator studies, the variability of image reorientation was significantly reduced (P = 0.0066 and 0.014, respectively) by using the marker method on dopamine images. The variability of reorientation using the marker method for a single operator with dopamine images was 3.0% coefficient of variation (CV), and for the interoperator study (5 different operators) this was 7.0% CV.
  
  
  CONCLUSIONS
  This study demonstrated that SPECT imaging of the dopamine system with external radioactive reference markers significantly reduced the variability of determining the angle of reorientation. This resulted in a standardized and consistent method of reorienting transaxial slices, allowing comparison within and between subjects of pre- and postsynaptic dopamine SPECT studies.
authors.affiliation: Department of Nuclear Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: D C
authors.initials: DC
authors.lastname: Vines
authors.forename: B D
authors.initials: BD
authors.lastname: Ivo
authors.forename: J R
authors.initials: JR
authors.lastname: Ballinger
authors.forename: M
authors.initials: M
authors.lastname: Ichise
mesh_terms: D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D002352:Carrier Proteins / Q000032:analysis*; D016022:Case-Control Studies; D003042:Cocaine / Q000031:analogs & derivatives; D003545:Cysteine / Q000031:analogs & derivatives; D050483:Dopamine Plasma Membrane Transport Proteins; D006801:Humans; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D015609:Organotechnetium Compounds; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals; D011954:Receptors, Dopamine / Q000032:analysis*; D015203:Reproducibility of Results; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D011954:Receptors, Dopamine; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; C059659:technetium Tc 99m bicisate; D003042:Cocaine; D003545:Cysteine