Journal of Nuclear Medicine Technology, Vol 27, Issue 2 112-116, Copyright © 1999 by Society of Nuclear Medicine
External radioactive reference markers in SPECT imaging of the dopamine system
DC Vines, BD Ivo, JR Ballinger and M Ichise
Department of Nuclear Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada.
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. CONCLUSION:
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.
