title: Effect of dual-source cardiac computed tomography on patient radiation dose in a clinical setting: comparison to single-source imaging.
abstract: BACKGROUND
  Dual-source computed tomography (DSCT) was introduced with significant hardware and software changes compared with single-source CT (SSCT), resulting in improved temporal resolution (83 ms) and the potential for improved image quality. The effect of these changes on radiation dose requirements for coronary CT angiography in clinical practice has not been investigated.
  
  
  OBJECTIVE
  We evaluated patient radiation dose and image quality of electrocardiogram (ECG)-gated helical techniques, using DSCT compared with SSCT for clinical imaging of the coronary arteries.
  
  
  METHODS
  DSCT data from 160 patients were evaluated; 82 patients (DSCT group 1) were imaged with early software, and 78 patients (DSCT group 2) were imaged with a later software version. Patients imaged with SSCT (n = 124) were the control group. Effective radiation dose values were estimated for all patients. Image noise was measured, and image quality was evaluated on a 5-point scale.
  
  
  RESULTS
  Effective dose values for DSCT group 2 (11.7 +/- 4.0 mSv) were not different from those for SSCT group (10.9 +/- 2.9 mSv); the highest doses, 13.2 +/- 3.2 mSv, were recorded for DSCT group 1 (P < 0.001). A decrease in image noise was observed for DSCT compared with SSCT (P <or= 0.001) as was an increase in image quality (P < 0.01). With optimized DSCT imaging, lower dose values were associated with (1) shorter scan range, (2) lower maximum tube current, and (3) lower fraction of R-R interval receiving maximum tube current.
  
  
  CONCLUSIONS
  ECG-gated helical DSCT can provide images of the coronary arteries with improved image quality and decreased noise without an increase in radiation dose compared with SSCT in clinical patient groups.
authors.affiliation: Cardiovascular Imaging Laboratory, Imaging Institute, Cleveland Clinic, Cleveland, OH 44195, USA. hallibs@ccf.org
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Halliburton
authors.forename: Srikanth
authors.initials: S
authors.lastname: Sola
authors.forename: Stacie A
authors.initials: SA
authors.lastname: Kuzmiak
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Obuchowski
authors.forename: Milind
authors.initials: M
authors.lastname: Desai
authors.forename: Scott D
authors.initials: SD
authors.lastname: Flamm
authors.forename: Paul
authors.initials: P
authors.lastname: Schoenhagen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001822:Body Burden; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011829:Radiation Dosage; D012062:Relative Biological Effectiveness; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult