title: Radiation dose exposure of computed tomography coronary angiography: comparison of dual-source, 16-slice and 64-slice CT.
abstract: BACKGROUND
  Dual-source CT (DSCT) promises a significant reduction of radiation dose exposure for coronary CT angiography (CTA). Large studies on radiation dose estimates are rare.
  
  
  OBJECTIVE
  To compare radiation dose estimates of DSCT with 16- and 64-slice multidetector CT (MDCT) for non-invasive coronary angiography.
  
  
  METHODS
  Retrospective data analysis was performed on 292 patients: 56 patients were examined with 16-slice MDCT, 38 patients with 64-slice MDCT and 202 patients using DSCT. The effective dose (ED) estimates were calculated for all patients from the dose-length product and the conversion factor k (0.017 mSv/mGy/cm), as recommended by current guidelines.
  
  
  RESULTS
  The mean (SD) ED for patients examined by 16-slice MDCT was 9.8 (1.8) mSv, for 64-slice MDCT 8.6 (2.8) mSv and for DSCT 11.4 (7.2) mSv. With a protocol of 100 kV tube voltage and 110 ms ECG pulsing window the mean (SD) ED was 3.8 (1.7) mSv for DSCT scanning. When DSCT with a tube voltage of 100 kV was used, a significant inverse correlation between heart rate and radiation dose exposure was found.
  
  
  CONCLUSIONS
  When standard protocols for coronary CTA with 16-, 64-slice MDCT and DSCT scanners are used, the radiation dose is still high. However, using optimised and individually adjusted protocols low estimated radiation doses can be achieved.
authors.affiliation: Department of Cardiology, Kerckhoff Heart Centre, Bad Nauheim, Germany. j.rixe@kerckhoff-klinik.de
authors.forename: J
authors.initials: J
authors.lastname: Rixe
authors.forename: G
authors.initials: G
authors.lastname: Conradi
authors.forename: A
authors.initials: A
authors.lastname: Rolf
authors.forename: A
authors.initials: A
authors.lastname: Schmermund
authors.forename: A
authors.initials: A
authors.lastname: Magedanz
authors.forename: D
authors.initials: D
authors.lastname: Erkapic
authors.forename: A
authors.initials: A
authors.lastname: Deetjen
authors.forename: C W
authors.initials: CW
authors.lastname: Hamm
authors.forename: T
authors.initials: T
authors.lastname: Dill
mesh_terms: D000368:Aged; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006339:Heart Rate / Q000528:radiation effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*