title: [Comparison of OS-EM reconstruction algorithms among different processors using a digital phantom dedicated for SPECT data evaluation].
abstract: OBJECTIVE
  In the OS-EM method, reconfigured images may be different among reconstruction image processors because the programs are highly arbitrary. The purpose of this study was to evaluate the difference in OS-EM algorithms among four different image processors using a digital phantom dedicated for SPECT data evaluation. The image processors used were GMS-5500A/PI (Toshiba), GENIE Xeleris (GE), e.soft (Siemens), and Odyssey FX (Shimadzu).
  
  
  METHODS
  Multiple images were reconstructed with OS-EM fluctuating the number of subsets and iterations. A region of interest (ROI) was placed on each image. The average counts, contrast, root mean square uncertainty (%RMSU), and normalized mean squared error (NMSE) of each ROI were calculated and compared with those of different image processors.
  
  
  RESULTS
  There was no significant difference in contrast among the algorithms. However, the average counts and (%RMSU were significantly different among algorithms as the number of updates increased. In addition, the minimums of NMSE were also different among algorithms.
  
  
  CONCLUSIONS
  In the OS-EM method, careful evaluation is necessary when using multiple image processors in research studies on the standardization of nuclear medicine imaging or in clinical applications.
authors.affiliation: Department of Radiology, Kurashiki Central Hospital.
authors.forename: Norikazu
authors.initials: N
authors.lastname: Matsutomo
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Furuya
authors.forename: Taichirou
authors.initials: T
authors.lastname: Yamao
authors.forename: Norimi
authors.initials: N
authors.lastname: Nishiyama
authors.forename: Takefumi
authors.initials: T
authors.lastname: Suruga
authors.forename: Shuichi
authors.initials: S
authors.lastname: Sugino
authors.forename: Shuuji
authors.initials: S
authors.lastname: Fujihara
authors.forename: Ryuji
authors.initials: R
authors.lastname: Yoshioka
mesh_terms: D000465:Algorithms; D016013:Likelihood Functions; D019047:Phantoms, Imaging; D015899:Tomography, Emission-Computed, Single-Photon