title: Monte Carlo simulation of the basic features of the GE Millennium MG single photon emission computed tomography gamma camera.
abstract: OBJECTIVE
  To describe and validate the simulation of the basic features of GE Millennium MG gamma camera using the GATE Monte Carlo platform.
  
  
  METHODS
  Crystal size and thickness, parallel-hole collimation and a realistic energy acquisition window were simulated in the GATE platform. GATE results were compared to experimental data in the following imaging conditions: a point source of (99m)Tc at different positions during static imaging and tomographic acquisitions using two different energy windows. The accuracy between the events expected and detected by simulation was obtained with the Mann-Whitney-Wilcoxon test. Comparisons were made regarding the measurement of sensitivity and spatial resolution, static and tomographic. Simulated and experimental spatial resolutions for tomographic data were compared with the Kruskal-Wallis test to assess simulation accuracy for this parameter.
  
  
  RESULTS
  There was good agreement between simulated and experimental data. The number of decays expected when compared with the number of decays registered, showed small deviation (≤ 0.007%). The sensitivity comparisons between static acquisitions for different distances from source to collimator (1, 5, 10, 20, 30 cm) with energy windows of 126-154 keV and 130-158 keV showed differences of 4.4%, 5.5%, 4.2%, 5.5%, 4.5% and 5.4%, 6.3%, 6.3%, 5.8%, 5.3%, respectively. For the tomographic acquisitions, the mean differences were 7.5% and 9.8% for the energy window 126-154 keV and 130-158 keV. Comparison of simulated and experimental spatial resolutions for tomographic data showed no statistically significant differences with 95% confidence interval.
  
  
  CONCLUSIONS
  Adequate simulation of the system basic features using GATE Monte Carlo simulation platform was achieved and validated.
authors.affiliation: Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal; Área Científica de Medicina Nuclear, Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Lisboa, Portugal. Electronic address: vieira.lina@sapo.pt.
authors.forename: L
authors.initials: L
authors.lastname: Vieira
authors.affiliation: Área Científica de Medicina Nuclear, Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Lisboa, Portugal.
authors.forename: T F
authors.initials: TF
authors.lastname: Vaz
authors.affiliation: HPP Medicina Molecular, SA, Porto, Portugal.
authors.forename: D C
authors.initials: DC
authors.lastname: Costa
authors.affiliation: Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Almeida
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D015902:Gamma Cameras; D008962:Models, Theoretical; D009010:Monte Carlo Method; D012984:Software; D018709:Statistics, Nonparametric; D013667:Technetium; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation*
chemical_list: D013667:Technetium
keywords: Cámara gamma; GATE; Gamma camera; Imágenes estáticas; Monte Carlo simulation; SPECT; Simulación de Monte Carlo; Static images