title: Effective radiation dose in CT colonography: is there a downward trend?
abstract: OBJECTIVE
  Radiation dose is an important drawback of computed tomography (CT) colonography, especially for its use as a screening tool for colorectal cancer. It is therefore important to know the present radiation dose. Our objective is to assess the effective radiation doses used for CT colonography and its trend over time.
  
  
  METHODS
  Institutions performing CT colonography research were asked to provide their CT colonography protocols. Median effective doses were calculated and compared with a 2007 inventory. Separate analyses were performed for protocols using intravenous contrast medium and for academic versus nonacademic institutions. Differences in effective dose were tested for significance, using Wilcoxon rank-sum or Wilcoxon signed-rank test.
  
  
  RESULTS
  Sixty-two of 109 (57%) institutions responded, providing protocols for 58 institutions. Median effective dose for daily practice protocols was 7.6 mSv (4.3 mSv and 2.0 mSv for supine and prone, respectively) and for screening 4.4 mSv (2.6 mSv and 2.0 mSv, respectively; P = .01). For daily practice with and without contrast medium, the median effective doses were 10.5 mSv and 4.0 mSv (P < .001), respectively. Academic and nonacademic institutions used similar doses (all comparisons P > .05). For institutions also participating in the 2007 inventory, effective dose for both daily practice and screening protocols were similar (P > .05).
  
  
  CONCLUSIONS
  In 2011 the median effective radiation dose for daily practice protocols was 7.6 mSv and for screening 4.4 mSv. Median effective doses have not decreased as compared to 2007. Academic and nonacademic institutions use similar radiation dose.
authors: Department of Radiology, Academic Medical Center, University of Amsterdam, the Netherlands. t.n.boellaard@amc.uva.nl
authors: Thierry N
authors: TN
authors: Boellaard
authors: Henk W
authors: HW
authors: Venema
authors: Geert J
authors: GJ
authors: Streekstra
authors: Jaap
authors: J
authors: Stoker
mesh_terms: D002985:Clinical Protocols; D023881:Colonography, Computed Tomographic / Q000639:trends*; D003287:Contrast Media; D006801:Humans; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011829:Radiation Dosage; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires
chemical_list: D003287:Contrast Media