Evaluation of Effective Dose Using the k-Factor of Optimal Scan Range for CT Examination


The American College of Radiology opened the computed tomography (CT) dose index registry (DIR) for general participation by all facilities in 2011. For each CT examination, data on volume CT dose index (CTDIvol), dose-length product (DLP), and, for body examinations, size-specific dose estimate (SSDE) were collected. However, effective dose is not estimated in DIR. The primary objective of this study was to estimate k-factor profile in detail at various scan positions with modified the ImPACT CT patient dosimetry. A tool that easily estimates the k-factor of suitable scan areas is essential for practical dose estimation in the DIR. We evaluated k-factor (effective dose/ DLP) profiles between a medical international radiation dose-five (MIRD-5) phantom positions using aImPACT software. As a result of this study, practicality of the k-factor profile method in clinical use was clarified. We speculate that a flexible k-factor improves the appropriateness of the E in hospital settings.

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Kobayashi, M. , Asada, Y. , Matsubara, K. , Haba, T. , Matsunaga, Y. , Kawaguchi, A. , Katada, K. , Toyama, H. , Koshida, K. , Kato, R. and Suzuki, S. (2015) Evaluation of Effective Dose Using the k-Factor of Optimal Scan Range for CT Examination. Open Journal of Radiology, 5, 172-148. doi: 10.4236/ojrad.2015.53021.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Chatfield, M.B. and Morin, R.L. (2013) The ACR Computed Tomography Dose Index Registry: The 5 Million Examination Update.
[2] AAPM Report No 204 (2011) Size-Specific Dose Estimates (SSDE) in Pediatric and Adult Body CT Examinations.
[3] DICOMsplement 127 (2007) CT Radiation Dose Reporting. DICOM Standards Committee.
[4] ICRP Publication 102 (2007) Managing Patient Dose in Multi-Detector Computed Tomography (MDCT).
[5] United Nations Scientific Committee on the Effects of Atomic Radiation (2010) UNSCEAR 2008 Report to the General Assembly with Scientific Annexes. Volume I.
[6] Shrimpton, P.C. and Wall, B.F. (2009) Effective Dose and Dose-Length Product in CT. Radiology, 250, 604.
[7] Kobayashi, M., Asada, Y., Matsubara, K., et al. (2014) Evaluation of Organ Doses and Effective Dose According to the ICRP Publication 110 Reference Male/Female Phantom and the Modified ImPACT CT Patient Dosimetry. Journal of Applied Clinical Medical Physics, 15, 1-10.
[8] Impactscan. “Impactscan.org.” (2015)
[9] Jones, D.G. and Shrimpton, P.C. (1993) Normalized Organ Doses for X-Ray Computed Tomography Calculated Using Monte Carlo Techniques NRPB Report SR250. National Radiological Protection Board, Didcot.
[10] ICRP Publication 103 (2009) The 2007 Recommendations of the International Commission on Radiological Protection.
[11] Zhang, Y., Li, X., Segars, W.P. and Samei, E. (2012) Organ Doses, Effective Doses, and Risk Indices in Adult CT: Comparison of Four Types of Reference Phantoms across Different Examination Protocols. Medical Physics, 39, 3404-3423.
[12] Einstein, A.J., Elliston, C.D., Arai, A.E., Chen, M.Y., Mather, R., Pearson, G.D., et al. (2010) Radiation Dose from Single-Heartbeat Coronary CT Angiography Performed with a 320-Detector Row Volume. Radiology, 254, 698-706.

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