New radiation dose saving technologies for 256-slice cardiac computed tomography angiography

Matthew J. Walker, Mark E. Olszewski, Milind Y. Desai, Sandra S. Halliburton, Scott D. Flamm

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Purpose: This paper aims to evaluate the dose reductions conferred by spiral dynamic z-collimation and axial adaptive z-collimation for retrospectively and prospectively ECG-referenced cardiac CTA, respectively, on a wide coverage, 256-slice CT scanner. Methods: Using typical data presented in the literature, a distribution of cardiac CT scan lengths was synthesized. To isolate the effect of z-overscan on effective radiation dose, 1,000 simulated patient scan lengths were then randomly sampled from this distribution and used for subsequent analysis. Results: Retrospectively ECG-gated spiral scans with dynamic z-collimation resulted in a mean relative effective dose reduction of 11.7 and 24.3% for MDCT with 40 and 80 mm z-axis detector coverage, respectively. Mean relative dose reduction of prospectively ECG-triggered axial scans with adaptive z-collimation on an 80 mm coverage scanner was 10.0%. Conclusion: Dynamic z-collimation for retrospectively ECG-gated spiral scanning and adaptive z-collimation for prospectively ECG-triggered axial scanning are both associated with a significant dose reduction on a wide coverage, 256-slice CT scanner.

Original languageEnglish (US)
Pages (from-to)189-199
Number of pages11
JournalInternational Journal of Cardiovascular Imaging
Issue numberSUPPL. 2
StatePublished - 2009
Externally publishedYes


  • 256-Slice MDCT
  • Coronary CT angiography
  • Dose efficiency
  • Low dose
  • Prospective triggering
  • Radiation exposure
  • Radiation reduction
  • Retrospective gating
  • Step-and-shoot

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine


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