title: Evaluation of varying physical acquisition parameters in gamma camera gated cardiac SPECT.
abstract: BACKGROUND
  There are various physical factors that limit the quality of the Single Photon Emission Computed Tomography (SPECT) images such as number of frames per projection, number of projections per scan and time per projection in gated myocardial SPECT scan.
  
  
  OBJECTIVE
  The aim of the present work was to evaluate physical acquisition parameters affecting the cardiac imaging to optimize the patient's examination time and image quality that are acquired with the gamma camera and workers radiation protection (through reducing time of radiation exposure) in cardiac SPECT facility. Cardiac functional parameters like ejection fraction (EF), end diastole volume (EDV), end systole volume (ESV) and total perfusion defect (TPD) were evaluated.
  
  
  METHODS
  Thirty patients were divided into three groups as follows: 1- Group (1): contains two sub-groups, one scanned with 8 frames per projection, the other with 16 frames per projection. 2- Group (2): contains two sub-groups, one scanned with 32 projections per scan, the other with 16 projections per scan. 3- Group (3): contains two sub-groups, one scanned at a time per projection of 20 s and the other scanned at 10 s per projection. Parameters such as the Ejection Fraction (EF), End Diastole Volume (EDV), End Systole Volume (ESV) and Total Perfusion Defect (TPD) in SPECT were compared for each group.
  
  
  RESULTS
  There was insignificant difference in the EF, EDV, ESV and TPD between the different groups concerning the number of frames per projection, number of projections per scan and time per projection.
  
  
  CONCLUSIONS
  The reduction of scan time to half or the number of projections per scan to half or increasing the number of frames per scan from 8 to 16 at the same duration has insignificant effect in the cardiac functional parameters used with gated SPECT scan.
authors.affiliation: Department of Biophysics, Faculty of science, Cairo University, Cairo, Giza, Egypt.
authors.forename: Reem H
authors.initials: RH
authors.lastname: Elgebaly
authors.affiliation: Department of Biophysics, Faculty of science, Cairo University, Cairo, Giza, Egypt.
authors.forename: Monira M
authors.initials: MM
authors.lastname: Rageh
authors.affiliation: Department of Critical care medicine, Faculty of Medicine, Cairo University, Cairo, Giza, Egypt.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Adel
mesh_terms: D005260:Female; D015902:Gamma Cameras; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012984:Software; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
keywords: Gated SPECT; filtered back projections (FBP); gamma camera; physical acquisition parameters