New radiation dose saving technologies for 256-slice cardiac computed tomography angiography
- 205 Downloads
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.
Keywords256-Slice MDCT Prospective triggering Retrospective gating Radiation exposure Radiation reduction Coronary CT angiography Step-and-shoot Low dose Dose efficiency
Conflict of interest
Matthew J. Walker and Mark E. Olszewski are employees of Philips Healthcare (Cleveland, OH, USA) and led the data simulation and statistical analysis. All authors reviewed and confirmed the results, and Scott D. Flamm takes scientific responsibility for data integrity.
- 1.Budoff MJ, Dowe D, Jollis JG et al (2008) Diagnostic performance of 64-multidetector row coronary computed tomographic angiography for evaluation of coronary artery stenosis in individuals without known coronary artery disease: results from the prospective multicenter ACCURACY (Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography) trial. J Am Coll Cardiol 52:1724–1732. doi: 10.1016/j.jacc.2008.07.031 PubMedCrossRefGoogle Scholar
- 6.Phurrough SE, Salive ME, Baldwin J et al. (2008) Decision memo for computed tomographic angiography (CAG-00385 N). In: Medicare National Coverage Determinations Manual. Sect. 220.1F. CMS publication 100-03. Centers for Medicare & Medicaid Services, Baltimore, MD, USA. http://www.cms.hhs.gov/mcd/viewdecisionmemo.asp?id=206. Accessed December 7, 2008
- 8.Budoff MJ, Achenbach S, Blumenthal RS et al (2006) Assessment of coronary artery disease by cardiac computed tomography: a scientific statement from the American Heart Association Committee on Cardiovascular Imaging and Intervention, Council on Cardiovascular Radiology and Intervention, and Committee on Cardiac Imaging, Council on Clinical Cardiology. Circulation 114:1761–1791. doi: 10.1161/CIRCULATIONAHA.106.178458 PubMedCrossRefGoogle Scholar
- 33.Toth TL, Cesmeli E, Ikhlef A et al. (2005) Image quality and dose optimization using novel x-ray source filters tailored to patient size. In: Flynn MJ (ed) Proceedings of the SPIE. Medical Imaging 2005: Physics of Medical Imaging, vol 5745. SPIE Press, Bellingham, WA, USA, pp 283–291Google Scholar
- 34.Kalender W (2008) Cardiac and thoracic CT should be carried out at low voltages. In: Glazer GM, Rubin GD (eds) Proceedings of the 10th Annual International Symposium on Multidetector-row CT. Available online at http://radiologycme.stanford.edu/2008mdct/handouts/
- 37.Goodman-Mumma C (2006) CT dose optimization. Med Imaging http://www.medicalimagingmag.com/issues/articles/2006-06_01.asp. Accessed 12 Dec 2008
- 43.Hausleiter J, Meyer T, Hermann F et al (2008) International prospective multicenter study on radiation dose estimates of coronary CT angiography in daily practice—the PROTECTION I study. J Am Coll Cardiol 51(suppl A):A137 (abstract)Google Scholar
- 45.Hausleiter J, Meyer T, Hadamitzky M et al (2007) Non-invasive coronary computed tomographic angiography for patients with suspected coronary artery disease: the coronary angiography by computed tomography with the use of a submillimeter resolution (CACTUS) trial. Eur Heart J 28:3034–3041. doi: 10.1093/eurheartj/ehm150 PubMedCrossRefGoogle Scholar
- 51.McCollough C, Cody D, Edyvean S et al. (2008) The measurement, reporting, and management of radiation dose in CT. Tech. Rep. 96 American Association of Physicists in Medicine, College Park, MD, USAGoogle Scholar
- 52.Shrimpton PC (2004) Assessment of patient dose in CT. Tech. Rep. NRPB-PE/1/2004 National Radiological Protection Board, Health Protection Agency, London, UKGoogle Scholar