title: Radiation dose for body CT protocols: variability of scanners at one institution.
abstract: OBJECTIVE
  The objective of our study was to determine, using an anthropomorphic phantom, whether patients are subject to variable radiation doses based on scanner assignment for common body CT studies.
  
  
  METHODS
  Twenty metal oxide semiconductor field effect transistor dosimeters were placed in a medium-sized anthropomorphic phantom of a man. Pulmonary embolism and chest, abdomen, and pelvis protocols were used to scan the phantom three times with GE Healthcare scanners in four configurations and one 64-MDCT Siemens Healthcare scanner. Organ doses were averaged, and effective doses were calculated with weighting factors.
  
  
  RESULTS
  The mean effective doses for the pulmonary embolism protocol ranged from 9.9 to 18.5 mSv and for the chest, abdomen, and pelvis protocol from 6.7 to 18.5 mSv. For the pulmonary embolism protocol, the mean effective dose from the Siemens Healthcare 64-MDCT scanner was significantly lower than that from the 16- and 64-MDCT GE Healthcare scanners (p < 0.001). The mean effective dose from the GE 4-MDCT scanner was significantly lower than that for the GE 16-MDCT scanner (p < 0.001) but not the GE 64-MDCT scanner (p = 0.02). For the chest, abdomen, and pelvis protocol, all mean effective doses from the GE scanners were significantly different from one another (p < 0.001), the lowest mean effective dose being found with use of a single-detector CT scanner and the highest with a 4-MDCT scanner. For the chest, abdomen, and pelvis protocols, the difference between the mean effective doses from the GE Healthcare and Siemens Healthcare 64-MDCT scanners was not statistically significant (p = 0.89).
  
  
  CONCLUSIONS
  According to phantom data, patients are subject to different radiation exposures for similar body CT protocols depending on scanner assignment. In general, doses are lowest with use of 64-MDCT scanners.
authors.affiliation: Department of Radiology, Duke University Medical Center, Erwin Rd., Box 3808, Durham, NC 27710, USA. jaffe002@mc.duke.edu
authors.forename: Tracy A
authors.initials: TA
authors.lastname: Jaffe
authors.forename: Terry T
authors.initials: TT
authors.lastname: Yoshizumi
authors.forename: Greta
authors.initials: G
authors.lastname: Toncheva
authors.forename: Colin
authors.initials: C
authors.lastname: Anderson-Evans
authors.forename: Carolyn
authors.initials: C
authors.lastname: Lowry
authors.forename: Chad M
authors.initials: CM
authors.lastname: Miller
authors.forename: Rendon C
authors.initials: RC
authors.lastname: Nelson
authors.forename: Carl E
authors.initials: CE
authors.lastname: Ravin
mesh_terms: D000328:Adult; D001822:Body Burden; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008297:Male; D019047:Phantoms, Imaging; D012062:Relative Biological Effectiveness; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*; D014915:Whole-Body Counting / Q000379:methods*