The magnitude of radiation dose imparted to
patients who underwent Head Computed Tomography examination in a large tertiary
hospital inSouth-Southern Nigeria has been estimated. CT-ExPO dosimetry
software was used to determine the effective and organ doses to the head region
of 40 adult patients. Scanning parameters were retrieved from the CT monitor
for both contrast-enhanced and non-contrast head CT examinations. The tube
potential ranged from 100 kVp to 120 kVp, while the mAs ranged from 127 mAs to
202 mAs. The mean values of the volume Computed Tomography Dose Index (CTDIvol) and Dose Length Product (DLP) for the
contrast-enhanced Head CT examination were 166.4 ± 39.6 mGy and 3568.6 ± 756.1
mGy·cm, respectively, while for the non-contrast
examination they were 86.6 ± 30.4 mGy and 2102.3 ± 870.3 mGy·cm, respectively. The effective doses were higher for the
contrast-enhanced study than for the non-contrast study by a factor of 1.6. Results
were compared with the European Union reference doses and other published data
and were found to be higher. Doses to the organs which compriseof brain, red bone marrow, thyroid and eye lens were
also estimated. The high variation in the doses in this study may be due to
differences in imaging protocols such as large range of mAs and scan lengths
and also the algorithm of the scanner.
References
[1]
National Council on Radiation Protection and Measurements (2009) Ionizing Radiation Exposure of the United States. National Council on Radiation Protection Report No. 160, National Council on Radiation Protection and Measurement, Bethesda, MD.
[2]
George, T., Rayan Babu, K.N. and Thomas, P.T. (2016) Reliability of Ultrasonography in the Diagnosis of Acute Appendicitis. International Surgery Journal, 3, 59-61. https://doi.org/10.18203/2349-2902.isj20151509
[3]
Rehani, M.M. and Berry, M. (2000) Radiation Doses in Computed Tomography. BMJ, 320, 593-594. https://doi.org/10.1136/bmj.320.7235.593
[4]
Berrington de Gonzalez, A. and Darby, S. (2004) Risk of Cancer from Diagnostic X-Rays: Estimates for the UK and 14 Other Countries. Lancet, 363, 345-351. https://doi.org/10.1016/S0140-6736(04)15433-0
[5]
Dehn, T.G. (2007) Ionizing Radiation Exposure from Radiologic Imaging: The Issue of What We Can Do. https://hmsa.com/portal/provider/Radiation_Safety_Provider_Edu_4pgs.pdf
[6]
International Commission on Radiological Protection (ICRP) Publication (2007) The 2007 Recommendations of the International Commission on Radiological Protection. Annals of the ICRP, 37, 1-332.
[7]
International Commission on Radiological Protection (ICRP) Publication (2007) Managing Patient Dose in Multi-Detector Computed Tomography (MDCT). Annals of the ICRP, 37, 1-63.
[8]
Pierce, D.A. and Preston, D.L. (2000) Radiation-Related Cancer Risks at Low Doses among Atomic Bomb Survivors. Radiation Research, 154, 178-186. https://doi.org/10.1667/0033-7587(2000)154[0178:RRCRAL]2.0.CO;2
[9]
Preston, D.L., Pierce, D.A., Shimizu, Y., Ron, E. and Mabuchi, K. (2003) Dose Response and Temporal Patterns of Radiation-Associated Solid Cancer Risks. Health Physics, 85, 43-46. https://doi.org/10.1097/00004032-200307000-00010
[10]
Sodickson, A., Baeyens, P.F., Andriole, K.P., Prevedello, L.M., Nawfel, R.D., Hanson, R. and Khorasani, R. (2009) Recurrent CT, Cumulative Radiation Exposure, and Associated Radiation—Induced Cancer Risks from CT of Adults. Radiology, 251, 175-184. https://doi.org/10.1148/radiol.2511081296
[11]
Smith-Bindman, R., Lipson, J., Marcus, R. Kim, K., Mahesh, M., Gould, R., Berrington de Gonzalez, A. and Miglioretti, D.L. (2009) Radiation Dose Associated with Common Computed Tomography Examinations and the Associated Lifetime Attributable Risk of Cancer. Archives of Internal Medicine, 169, 2078-2086. https://doi.org/10.1001/archinternmed.2009.427
[12]
Garba, I., Engel-Hills, P., Davidson, F. and Tabari, A.M. (2015) Computed Tomography Dose Index for Head CT in Northern Nigeria. Radiation Protection Dosimetry, 165, 98-101.
[13]
Ogbole, G.I. and Obed, R.I. (2014) Radiation Doses in Computed Tomography: Need for Optimization and Application of Dose Reference Levels in Nigeria. West African Journal of Radiology, 21, 1-6.
[14]
Abdulkadir, M.K., Schandorf, C. and Hasford, F. (2016) Determination of Computed Tomography Diagnostic Reference Levels of North-Central Nigeria. The Pacific Journal of Science and Technology, 17, 341-349.
[15]
European Commission (1999) Radiation Protection 109. Guidance on Diagnostic Reference Levels (DRLs) for Medical Exposures. Office for Official Publications of the European Communities, Luxembourg.
[16]
Adejoh, T., Christian, N.C., Nkubil, F.B. and Dlama, J.Z. (2015) Effective Dose Levels from Computed Tomography of the Head during Contrast Studies in Nigeria. Health, 7, 915-919.
[17]
Osei, E.K. and Darko, J. (2013) A Survey of Organ Equivalent and Effective Doses from Diagnostic Radiology Procedures. ISRN Radiology, 2013, 9.
[18]
Akpochafor, M.O., Omojola, A.D., Habeebu, M.Y., Ezike, J.C., Adeneye, S.O., Ekpo, M.E., Aweda, M.A., Opadele, A.E. and Orotoye, T.A. (2018) Computed Tomography Organ Dose Determination Using Impact Simulation Software: Our Findings in South-West Nigeria. Eurasian Journal of Medicine and Oncology, 2, 165-172.
