title: Radiation dose from cardiac computed tomography before and after implementation of radiation dose-reduction techniques.
abstract: BACKGROUND
  Cardiac computed tomography angiography (CCTA) can accurately diagnose coronary artery disease, but radiation dose from this procedure is of concern.
  
  
  OBJECTIVE
  To determine whether a collaborative radiation dose-reduction program would be associated with reduced radiation dose in patients undergoing CCTA in a statewide registry over a 1-year period and to define its effect on image quality.
  
  
  METHODS
  A prospective, controlled, nonrandomized study conducted during a control period (July-August 2007), an intervention period (September 2007-April 2008), and a follow-up period (May-June 2008) at 15 hospital imaging centers participating in the Advanced Cardiovascular Imaging Consortium in Michigan, which included small community hospitals and large academic medical centers. A total of 4995 sequential patients undergoing CCTA for suspected coronary artery disease were enrolled; 4862 patients (97.3%) had complete radiation data for analysis.
  
  
  METHODS
  A best-practice CCTA scan model was used, which included minimized scan range, heart rate reduction, electrocardiographic-gated tube current modulation, and reduced tube voltage in suitable patients.
  
  
  METHODS
  Primary outcomes included dose-length product and effective radiation dose from all phases of the CCTA scan. Secondary outcomes were image quality assessed by a 4-point scale (1 indicated excellent; 2, good; 3, adequate; and 4, nondiagnostic) and frequency of diagnostic-quality scans.
  
  
  RESULTS
  Compared with the control period, patients' estimated median radiation dose in the follow-up period was reduced by 53.3% (dose-length product decreased from 1493 mGy x cm [interquartile range {IQR}, 855-1823 mGy x cm] to 697 mGy x cm [IQR, 407-1163 mGy x cm]; P < .001) and effective dose from 21 mSv (IQR, 12-26 mSv) to 10 mSv (IQR, 6-16 mSv) (P < .001). The greatest reduction in dose occurred at low-volume sites. There were no significant changes in median image quality assessment during the control period compared with the follow-up period (median image quality of 2 [images rated as good] vs median image quality of 2; P = .13) or frequency of diagnostic-quality scans (554/620 patients [89%] vs 769/835 patients [92%]; P = .07).
  
  
  CONCLUSIONS
  Consistent application of currently available dose-reduction techniques was associated with a marked reduction in estimated radiation doses in a statewide CCTA registry, without impairment of image quality.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT00640068.
authors.affiliation: Cardiology Division, William Beaumont Hospital, 3601 W 13 Mile Rd, Royal Oak, MI 48073, USA. GRaff@beaumont.edu
authors.forename: Gilbert L
authors.initials: GL
authors.lastname: Raff
authors.forename: Kavitha M
authors.initials: KM
authors.lastname: Chinnaiyan
authors.forename: David A
authors.initials: DA
authors.lastname: Share
authors.forename: Tauqir Y
authors.initials: TY
authors.lastname: Goraya
authors.forename: Ella A
authors.initials: EA
authors.lastname: Kazerooni
authors.forename: Mauro
authors.initials: M
authors.lastname: Moscucci
authors.forename: Ralph E
authors.initials: RE
authors.lastname: Gentry
authors.forename: Aiden
authors.initials: A
authors.lastname: Abidov
mesh_terms: D000328:Adult; D000368:Aged; D017023:Coronary Angiography / Q000592:standards; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D011446:Prospective Studies; D011829:Radiation Dosage; D012042:Registries; D014057:Tomography, X-Ray Computed / Q000592:standards