Evaluation of Local Diagnostic Reference Levels for Paediatric and Adult Patients Undergoing Head Computed Tomography Examination in Amhara Regional States, Ethiopia

Document Type : Original Paper


1 Addis Ababa University, Tikur Anbessa Hospital Department of Radiology

2 Physics, College of natural Computational Sciences, Woldia University, woldia, Ethiopia


Introduction: During computed tomography examinations variation of dose for pediatric and adults has been increasing widely, even when automated exposure control is used. Hence, the objective of this study was to assess the computed tomography head local diagnostic reference levels in the Amhara region.
Material and Methods: Active computed tomography scanners in the Amhara region were identified and then both retrospective and prospective technique was used to collect data for pediatric and adult head examinations. Scan parameters, patient profiles, and CT dose indicators were collected from 334 patients.  Pediatric patients were grouped into three age (years) groups of (1-5, 5-10, and 10-15). The local diagnostic reference levels were established from third quartile values of computed tomography dose index and dose length product. SPSS software version 26 and Microsoft Excel 2016 were used for the entire data analysis.
Results: The calculated 3rd quartile values  of computed tomography dose index and dose length product, for adult head examinations, were 49 mGy and 1806 mGy.cm respectively. Similarly, for pediatric head CT scan, computed tomography dose index (mGy) and dose length product (mGy.cm) values for age (years) groups (1-5, 5-10, and 10-15) were (30, 2015); (35, 1221); and (43, 2051) respectively.The investigated 3rd quartile values of computed tomography dose index and dose length product were higher than other national and international reported values.
Conclusion: For all pediatric and adult patients , there are differences in the local diagnostic reference levels between the CT centers and the same scanners, indicating the need for dose optimization.


Main Subjects

  1. Ngaram SM, Mohammed IB. Study of radiation doses in adult and paediatric patients undergoing computed tomography examination in Nigeria. Advances in Computed Tomography. 2019 Sep 30;8(03):37.
  2. Dixon AK, Dendy P. Spiral CT: how much does radiation dose matter?. The Lancet. 1998 Oct 3;352(9134):1082-3.
  3. Pages J, Buls N, Osteaux M. CT doses in children: a multicentre study. The British Journal of Radiology. 2003 Nov;76(911):803-11.
  4. Martin CJ, Sookpeng S. Setting up computed tomography automatic tube current modulation systems. Journal of Radiological Protection. 2016 Aug 3;36(3):R74.
  5. Hatziioannou K, Papanastassiou E, Delichas M, Bousbouras P. A contribution to the establishment of diagnostic reference levels in CT. The British journal of radiology. 2003 Aug;76(908):541-5.
  6. Lessick J, Abadi S, Agmon Y, Keidar Z, Carasso S, Aronson D, et al. Multidetector computed tomography predictors of late ventricular remodeling and function after acute myocardial infarction. European journal of radiology. 2012 Oct 1;81(10):2648-57.
  7. Marin JR, Sengupta D, Bhargavan‐Chatfield M, Kanal KM, Mills AM, et al. Variation in pediatric cervical spine computed tomography radiation dose index. Academic Emergency Medicine. 2015 Dec;22(12):1499-505.
  8. Rehani MM. ICRP and IAEA actions on radiation protection in computed tomography. Annals of the ICRP. 2012 Oct;41(3-4):154-60.
  9. Guena MN, Nguemeleu DN, Ndah TN, Moifo B. An assessment of both patients and medical staff awareness of the risks of ionizing radiation from CT scan in Cameroon. Open Journal of Radiology. 2017 Aug 23;7(3):199-208.
  10. Dellie ST, Admassie D, Ewnetu Y. An assessment of final-year medical students and interns awareness of radiation exposure to common diagnostic imaging procedures. Advances in Radiology. 2014 Jul 24;2014.
  11. Zewdu M, Kadir E, Berhane M. Assessment of pediatrics radiation dose from routine x-ray examination at Jimma University Hospital, Southwest Ethiopia. Ethiopian Journal of Health Sciences. 2017 Aug 22;27(5):481-90.
  12. Gower-Thomas K, Lewis MH, Shiralkar S, Snow M, Galland RB, Rennie A. Doctors' knowledge of radiation exposures is deficient. Bmj. 2002 Apr 13;324(7342):919.
  13. Vañó E, Miller DL, Martin CJ, Rehani MM, Kang K, Rosenstein M, et al. ICRP publication 135: diagnostic reference levels in medical imaging. Annals of the ICRP. 2017 Oct;46(1):1-44.
  14. Shrimpton PC, Hillier MC, Lewis MA, Dunn M. National survey of doses from CT in the UK: 2003. The British journal of radiology. 2006 Dec;79(948):968-80.
  15. Ali ST, Hamad MM, Ayad CE, Abdalla EA, Ahmed AS. Evaluation of the technical specifications of computerized tomography scanners in Jazan. Sudan Medical Monitor. 2013 Jul 1;8(3):159.
  16. Tsapaki V, Damilakis J, Paulo G, Schegerer AA, Repussard J, Jaschke W, et al. CT diagnostic reference levels based on clinical indications: results of a large-scale European survey. European Radiology. 2021 Jul;31:4459-69.
  17. Sakhnini A. CT radiation dose optimization and reduction for routine head, chest and abdominal CT examinations. Radiol Diagn Imaging. 2017;2(1):1-4.
  18. Ekpo EU, Adejoh T, Akwo JD, Emeka OC, Modu AA, Abba M, et al. Diagnostic reference levels for common computed tomography (CT) examinations: results from the first Nigerian nationwide dose survey. Journal of radiological protection. 2018 Mar 13;38(2):525.
  19. Salama DH, Vassileva J, Mahdaly G, Shawki M, Salama A, Gilley D, et al. Establishing national diagnostic reference levels (DRLs) for computed tomography in Egypt. Physica medica. 2017 Jul 1;39:16-24.
  20. Nyathi M, Shivambu GI. Local Diagnostic Reference Levels for Common Computed Tomography Procedures at a Tertiary Hospital in South Africa. Iranian Journal of Medical Physics/Majallah-I Fīzīk-I Pizishkī-i Īrān. 2019 Sep 1;16(5).
  21. Korir GK, Wambani JS, Korir IK, Tries MA, Boen PK. National diagnostic reference level initiative for computed tomography examinations in Kenya. Radiation protection dosimetry. 2016 Feb 1;168(2):242-52.
  22. Kharuzhyk SA, Matskevich SA, Filjustin AE, Bogushevich EV, Ugolkova SA. Survey of computed tomography doses and establishment of national diagnostic reference levels in the Republic of Belarus. Radiation protection dosimetry. 2010 Apr 1;139(1-3):367-70.
  23. Verdun FR, Gutierrez D, Vader JP, Aroua A, Alamo-Maestre LT, Bochud F, et al. CT radiation dose in children: a survey to establish age-based diagnostic reference levels in Switzerland. European radiology. 2008 Sep;18:1980-6.
  24. Ataç GK, Parmaksız A, İnal T, Bulur E, Bulgurlu F, Öncü T, et al. Patient doses from CT examinations in Turkey. Diagnostic and Interventional Radiology. 2015 Sep;21(5):428.
  25. Järvinen H, Seuri R, Kortesniemi M, Lajunen A, Hallinen E, Savikurki-Heikkilä P, et al. Indication-based national diagnostic reference levels for paediatric CT: a new approach with proposed values. Radiation protection dosimetry. 2015 Jul 1;165(1-4):86-90.
  26. Kritsaneepaiboon S, Trinavarat P, Visrutaratna P. Survey of pediatric MDCT radiation dose from university hospitals in Thailand: a preliminary for national dose survey. Acta Radiologica. 2012 Sep;53(7):820-6.
  27. Safety Standards for protecting people and the environment General Safety Guide No. GSG-7 Occupational Radiation Protection Jointly sponsored by. Gen Saf Guid Int At Energy Agency [Internet]. 2018;360. Available from: http://www-ns.iaea.org/standards/
  28. European Society of Radiology. European Guidelines on DRLs for Paediatric Imaging. PiDRL. 2015Sep;1–






Volume 20, Issue 5
September and October 2023
Pages 252-256
  • Receive Date: 16 May 2022
  • Revise Date: 16 August 2022
  • Accept Date: 11 September 2022