title: Estimating Effective Dose of Radiation From Pediatric Cardiac CT Angiography Using a 64-MDCT Scanner: New Conversion Factors Relating Dose-Length Product to Effective Dose.
abstract: OBJECTIVE
  The purpose of this study is to determine the conversion factors that enable accurate estimation of the effective dose (ED) used for cardiac 64-MDCT angiography performed for children.
  
  
  METHODS
  Anthropomorphic phantoms representative of 1- and 10-year-old children, with 50 metal oxide semiconductor field-effect transistor dosimeters placed in organs, underwent scanning performed using a 64-MDCT scanner with different routine clinical cardiac scan modes and x-ray tube potentials. Organ doses were used to calculate the ED on the basis of weighting factors published in 1991 in International Commission on Radiological Protection (ICRP) publication 60 and in 2007 in ICRP publication 103. The EDs and the scanner-reported dose-length products were used to determine conversion factors for each scan mode. The effect of infant heart rate on the ED and the conversion factors was also assessed.
  
  
  RESULTS
  The mean conversion factors calculated using the current definition of ED that appeared in ICRP publication 103 were as follows: 0.099 mSv · mGy-1· cm-1, for the 1-year-old phantom, and 0.049 mSv · mGy-1· cm-1, for the 10-year-old phantom. These conversion factors were a mean of 37% higher than the corresponding conversion factors calculated using the older definition of ED that appeared in ICRP publication 60. Varying the heart rate did not influence the ED or the conversion factors.
  
  
  CONCLUSIONS
  Conversion factors determined using the definition of ED in ICRP publication 103 and cardiac, rather than chest, scan coverage suggest that the radiation doses that children receive from cardiac CT performed using a contemporary 64-MDCT scanner are higher than the radiation doses previously reported when older chest conversion factors were used. Additional up-to-date pediatric cardiac CT conversion factors are required for use with other contemporary CT scanners and patients of different age ranges.
authors.affiliation: 1 Department of Medicine, Cardiology Division, Columbia University Medical Center, New York, NY.
authors.forename: Sigal
authors.initials: S
authors.lastname: Trattner
authors.affiliation: 2 Department of Pediatrics, Pediatric Cardiology Division, New York-Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, New York, NY.
authors.forename: Anjali
authors.initials: A
authors.lastname: Chelliah
authors.affiliation: 3 Philips Healthcare Research, Eindhoven, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: Prinsen
authors.affiliation: 4 Department of Radiology, Columbia University Medical Center, New York, NY.
authors.forename: Carrie B
authors.initials: CB
authors.lastname: Ruzal-Shapiro
authors.affiliation: 5 Radiological Research Accelerator Facility, Center for Radiological Research, Columbia University, Irvington, NY.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Xu
authors.affiliation: 4 Department of Radiology, Columbia University Medical Center, New York, NY.
authors.forename: Sachin
authors.initials: S
authors.lastname: Jambawalikar
authors.affiliation: 6 Radiation Safety Office, Columbia University Medical Center, New York, NY.
authors.forename: Maxwell
authors.initials: M
authors.lastname: Amurao
authors.affiliation: 7 Department of Medicine, Cardiology Division and Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, 622 W 168th St, PH 10-203A, New York, NY 10032.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Einstein
mesh_terms: D000465:Algorithms; D002648:Child; D000072226:Computed Tomography Angiography / Q000295:instrumentation* / Q000379:methods; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008954:Models, Biological; D061330:Multidetector Computed Tomography / Q000295:instrumentation* / Q000379:methods; D019047:Phantoms, Imaging; D000069079:Radiation Exposure / Q000032:analysis*; D011834:Radiation Monitoring / Q000379:methods*; D012062:Relative Biological Effectiveness; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: conversion factor; dose-length product; effective dose; pediatric cardiac CT; radiation