title: Radiation dose values for various coronary calcium scoring protocols in dual-source CT.
abstract: OBJECTIVE
  The purpose of this study was to assess the radiation dose and associated image noise of previously suggested calcium scoring protocols using dual-source CT.
  
  
  METHODS
  One hundred consecutive patients underwent coronary calcium scoring using dual-source CT. Patients were randomly assigned to five different protocols: retrospective ECG-gating and tube current reduction to 4% outside the pulsing window at 120 (protocol A) and 100 kV (B), prospective ECG-triggering at 120 (C) and 100 kV (D), and prospective ECG-triggering at 100 kV with attenuation-based tube current modulation (E). Radiation dose parameters and image noise were determined and compared.
  
  
  RESULTS
  Protocol A resulted in an effective dose of 1.3 +/- 0.2 mSv, protocol B in 0.8 +/- 0.2 mSv, protocol C in 1.0 +/- 0.2 mSv, protocol D in 0.6 +/- 0.1 mSv, and protocol E in 0.7 +/- 0.1 mSv. Effective doses were significantly lower (P < 0.001) with 100 kV when compared to 120 kV protocols, and were significantly lower (P < 0.001) for prospective versus retrospective ECG-gating. No significant difference was found between protocol D and E. Significant negative correlations were found between the CTDI(vol) and heart rate for both retrospective ECG-gating protocols (protocol A: r = -0.98, P < 0.001; protocol B: r = -0.83, P < 0.001). The mean image noise was 29.0 +/- 6.7 HU, with no significant differences between the five protocols. The image noise was significantly correlated with the body weight (r = 0.21, P < 0.05) and BMI (r = 0.31, P < 0.01).
  
  
  CONCLUSIONS
  Effective dose of calcium scoring using dual-source CT ranges from 0.6 to 1.3 mSv. Prospective triggering and lower tube voltage significantly reduces the radiation but yield similar image noise.
authors.affiliation: University Hospital Zurich, Zurich, Switzerland.
authors.forename: Paul
authors.initials: P
authors.lastname: Stolzmann
authors.forename: Sebastian
authors.initials: S
authors.lastname: Leschka
authors.forename: Thomas
authors.initials: T
authors.lastname: Betschart
authors.forename: Lotus
authors.initials: L
authors.lastname: Desbiolles
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Flohr
authors.forename: Borut
authors.initials: B
authors.lastname: Marincek
authors.forename: Hatem
authors.initials: H
authors.lastname: Alkadhi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002114:Calcinosis / Q000000981:diagnostic imaging*; D016009:Chi-Square Distribution; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*