title: Image registration accuracy of an in-house developed patient transport system for PET/CT+MR and SPECT+CT imaging.
abstract: OBJECTIVE
  The aim of this study was to investigate the registration accuracy of a newly developed patient shuttle system that can integrate different scanners by patient transfer without repositioning for 'hardware'-based image fusion. We aimed to assess the registration accuracy of image fusion in two different settings: a trimodality PET/CT+MR system and a SPECT+CT system.
  
  
  METHODS
  In this prospective study, 43 patients underwent either sequential PET/CT and MR (n=31) or sequential SPECT and diagnostic CT (D-CT) (n=12). A side-loading patient shuttle system was used for patient transport. For PET/CT+MR, hardware-only coregistration was performed and then validated with anatomical landmarks on CT and MR. SPECT+D-CT image fusion was performed with external cobalt-57 markers and manual fusion. Registration accuracy was analysed by anatomical landmarks on the attenuation correction CT and the D-CT.
  
  
  RESULTS
  For the PET/CT+MR system, the mean offset between original CT and MR images in all 31 patients was 8.1±5.7 mm in the X-axis, 5±4 mm in the Y-axis and 4.9±5.6 mm in the Z-axis. The validation of the cobalt-57 marker-assisted SPECT+D-CT fusion yielded offsets of 0.7±1.7 mm in the X-axis, 2.1±1.7 mm in the Y-axis and 0.8±1.8 mm in the Z-axis.
  
  
  CONCLUSIONS
  Sequential PET/CT+MR and SPECT+D-CT imaging using a dedicated patient shuttle system is feasible, resulting in mean offsets between data sets of 10.7 mm using the gantry laser system and 2.4 mm with fiducial markers.
authors.affiliation: aDepartment of Nuclear Medicine, University Hospital of Zurich, Zurich bInnovation Design Center, Thalwil, Switzerland.
authors.forename: Andrei
authors.initials: A
authors.lastname: Samarin
authors.forename: Felix P
authors.initials: FP
authors.lastname: Kuhn
authors.forename: Fredrik
authors.initials: F
authors.lastname: Brandsberg
authors.forename: Gustav
authors.initials: G
authors.lastname: von Schulthess
authors.forename: Irene A
authors.initials: IA
authors.lastname: Burger
mesh_terms: D000368:Aged; D003952:Diagnostic Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010360:Patient Transfer / Q000379:methods*; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D018511:Systems Integration; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed