title: Pediatric 64-MDCT coronary angiography with ECG-modulated tube current: radiation dose and cancer risk.
abstract: OBJECTIVE
  The purpose of our study was to measure the radiation dose from ECG-gated CT coronary angiography in children and to estimate the cancer risk associated with the radiation dose.
  
  
  METHODS
  Organ doses were measured with a 5-year-old pediatric phantom and thermoluminescent dosimeters on a 64-MDCT scanner. Four retrospectively ECG-gated CT coronary angiography protocols with four simulated heart rates and the corresponding pitches were studied. The lifetime attributable risk of cancer incidence was estimated for children in the United States and Hong Kong according to the National Academies Biologic Effects of Ionizing Radiation VII report.
  
  
  RESULTS
  The effective doses were 16.45, 12.17, 11.97, and 11.81 mSv for the four protocols, respectively. The corresponding lifetime attributable risks estimated for 5-year-old U.S. boys and girls were 0.14%-0.20% and 0.43%-0.60%, respectively, and for 5-year-old Hong Kong boys and girls were 0.22%-0.33% and 0.61%-0.85%. In relation to the total cancer incidence (baseline cancer incidence plus lifetime attributable risk), lifetime attributable risk from radiation exposure contributed up to 0.99% and 3.51% for Hong Kong boys and girls and up to 0.46% and 1.57% for U.S. boys and girls.
  
  
  CONCLUSIONS
  Our results suggest that radiation dose and cancer risk of CT coronary angiography to pediatric patients are not negligible, more so in Hong Kong children than in U.S. children. Therefore, these examinations should be well justified clinically.
authors.affiliation: Department of Diagnostic Radiology, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Rd., Hong Kong.
authors.forename: Bingsheng
authors.initials: B
authors.lastname: Huang
authors.forename: Martin Wai-Ming
authors.initials: MW
authors.lastname: Law
authors.forename: Henry Ka-Fung
authors.initials: HK
authors.lastname: Mak
authors.forename: Stephen Ping-Fai
authors.initials: SP
authors.lastname: Kwok
authors.forename: Pek-Lan
authors.initials: PL
authors.lastname: Khong
mesh_terms: D001822:Body Burden; D002648:Child; D002675:Child, Preschool; D017023:Coronary Angiography / Q000379:methods* / Q000706:statistics & numerical data*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008955:Models, Cardiovascular; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D012189:Retrospective Studies; D018570:Risk Assessment; D014481:United States / Q000453:epidemiology