National indication-based diagnostic reference level values in computed tomography: Preliminary results from Ghana

  • Benard Ohene Botwe
    Corresponding author at: Radiography Department, School of Biomedical and Allied Health Sciences, College of Health Sciences, University of Ghana, Korle-Bu Campus, Accra, Ghana.
    Radiography Department, School of Biomedical and Allied Health Sciences, College of Health Sciences, University of Ghana, Korle-Bu Campus, Accra, Ghana

    Department of Nuclear Safety and Security, School of Nuclear and Allied Sciences, University of Ghana, Atomic Campus, Accra, Legon, Ghana
    Search for articles by this author
  • Cyril Schandorf
    Department of Nuclear Safety and Security, School of Nuclear and Allied Sciences, University of Ghana, Atomic Campus, Accra, Legon, Ghana
    Search for articles by this author
  • Stephen Inkoom
    Medical Physics Department, School of Nuclear and Allied Sciences, University of Ghana, Atomic Campus, Accra, Ghana

    Radiation Protection Institute (RPI), Ghana Atomic Energy Commission, Accra, Ghana
    Search for articles by this author
  • Augustine Faanu
    Radiological and Non-ionizing Radiation Directorate, Nuclear Regulatory Authority, Accra, Ghana
    Search for articles by this author
  • Linn Rolstadaas
    Clinic of Radiology and Nuclear Medicine, St. Olavs University Hospital, Trondheim, Norway
    Search for articles by this author
  • Pål Erik Goa
    Clinic of Radiology and Nuclear Medicine, St. Olavs University Hospital, Trondheim, Norway

    Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway
    Search for articles by this author
Published:March 25, 2021DOI:


      • In Ghana there are no established national indication-based diagnostic reference levels.
      • First national indication-based diagnostic reference levels have been developed.
      • The developed diagnostic reference levels are recommended to be used to manage dose in Ghana.



      This study was conducted to develop national indication-based DRL values for common indications of adult computed tomography (CT) examinations for clinical application in Ghana.

      Materials and methods

      The methodological approach recommended by the International Commission on Radiological Protection (ICRP), Publication 135, for the development of DRLs, was employed. Studies on CT infrastructure, common indications and quality control tests were first undertaken. A sample of 20 CT dose descriptor/quantity data sets were collected from each centre for each indication. Overall, 3960 data sets were collected for all identified common indications from 71.4% of the total CT scanners in Ghana (25/35). The data were collected from image folders reported and accepted by radiologists. The objective image quality was assessed through a signal to noise ratio (SNR) analysis prior to using the data and extracting DRL values.


      Clinical indications and their respective DRL values in terms of volume weighted CT dose index (CTDIvol) and dose length product (DLP) were cerebrovascular accident (CVA)/stroke (77 mGy; 1313, head trauma/injury (76 mGy; 1596, brain tumour/space occupying lesion (SOL) (77 mGy; 2696, lung tumour/cancer (12 mGy; 828 and chest lesion with chronic kidney disease (CKD) (13 mGy; 467 Others were abdominopelvic lesion (17 mGy; 1299, kidney stones (15 mGy; 731, urothelial malignancy/CT-intravenous urogram (CT-IVU) (11 mGy; 1449 and pulmonary embolism (PE) (14 mGy; 942


      National Indication-based DRL values developed in this study are recommended to be used to manage CT radiation dose in Ghana.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Physica Medica: European Journal of Medical Physics
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Gao Y.
        • Quinn B.
        • Mahmood U.
        • Long D.
        • Erdi Y.
        • St. Germain J.
        • et al.
        A comparison of pediatric and adult CT organ dose estimation methods.
        BMC Med Imaging. 2017; 17: 2-17
        • Liang C.R.
        • Chen P.X.H.
        • Kapur J.
        • Ong M.K.L.
        • Quek S.T.
        • Kapur S.C.
        Establishment of institutional diagnostic reference level for computed tomography with automated dose-tracking software.
        J Med Radiat Sci. 2017; 64: 82-89
        • Kanal K.M.
        • Butler P.F.
        • Sengupta D.
        • Bhargavan-Chatfield M.
        • Coombs L.P.
        • Morin R.L.U.S.
        diagnostic reference levels and achievable Doses for 10 adult CT examinations.
        Radiology. 2017; 284: 120-133
      1. UNSCEAR. UNSCEAR 2008 Report. Sources and effects of ionizing radiation. Volume I: Sources Report to the General Assembly, Scientific Annexes A and B. UNSCEAR 2008 Report. United Nations Scientific Committee on the Effects of Atomic Radiation. New York: United Nations; 2010.

        • Yeh D.M.
        • Tsai H.Y.
        • Tyan Y.S.
        • Chang Y.C.
        • Pan L.K.
        • Chen T.R.
        The population effective dose of medical computed tomography examinations in Taiwan for 2013.
        PLoS ONE. 2016; 11e0165526
      2. IAEA. Diagnostic Reference Levels (DRLs) in Medical Imaging, [Accessed 20 October 2017].

        • ICRP
        The 2007 recommendations of the international commission on radiological protection. ICRP publication 103.
        Ann ICRP. 2007; 37: 1-332
        • ICRP Publication
        105. Radiation protection in medicine.
        Ann ICRP. 2007; 37: 1-63
      3. Lajunen, A. Indication-based diagnostic reference levels for adult CT-examinations in Finland. Radiat Protect Dosimetry 2015;165(1-4): 95-97.

        • Vassileva J.
        • Rehani M.
        Diagnostic reference levels.
        Am J Roentgenol. 2015; 204: W1-W3
        • ICRP
        Diagnostic reference levels in medical imaging. ICRP Publication 135.
        Ann. ICRP. 2017; 46
        • ICRP
        Radiological Protection and Safety in Medicine (Report 73).
        Ann ICRP. 1996; 26: 1-31
      4. IAEA GSR Part 3. Radiation protection and Safety of radiation sources: International basic Safety standards. Vienna: IAEA; 2014.

      5. European Society of Radiology. EuroSafe Imaging Call for Action 2018, [Accessed 14 November 2018].

        • Paulo G.
        • Damilakis J.
        • Tsapaki V.
        • Schegerer A.A.
        • Repussard J.
        • Jaschke W.
        • et al.
        European Society of Radiology. Diagnostic Reference Levels based on clinical indications in computed tomography: a literature review. Insights into.
        Imaging. 2020; 11: 96
      6. Damilakis J, Frija G, Hierath M, Jaschke W, Mayerhofer-Sebera U, Paulo G, et al. European study on clinical diagnostic reference levels for x-ray medical imaging most studies conducted in CT DRLs have been anatomic DRLs, DRLs_final_published-on-website.pdfICRP, 2017 [Accessed 12 November 2019].

      7. Vock P, Frija G. Diagnostic reference levels based on clinical indications. Poster presentation. EuroSafe Imaging Congress 2016; No ESI-0034. DOI: 10.1594/esi2016/ESI-0034.

      8. European Society of Radiology. Diagnostic reference levels, . [Accessed 19 February 2018].

      9. European Association of Nuclear Medicine, (EANM), European Federation of Organisations for Medical Physics (EFOMP), European Federation of Radiographer Societies (EFRS), European Society of Radiology (ESR) and European Society for Radiotherapy and Oncology (ESTRO). Common strategic research agenda for radiation protection in medicine. Insights into Imaging 2017;8(1):183–197.

        • Botwe B.
        • Schandorf C.
        • Inkoom S.
        • Faanu A.
        An investigation into the infrastructure and management of Computerized Tomography units in Ghana.
        J Med Imaging Radiat Sci. 2020; 51: 165-172
        • Botwe B.
        • Schandorf C.
        • Inkoom S.
        • Faanu A.
        Status of quality management systems in computed tomography facilities in Ghana.
        Radiol Technol. 2020; 91: 324-332
        • Bushberg J.T.
        • Seibert J.A.
        • Leidholt M.E.
        • Boone J.M.
        The essential physics of medical imaging.
        2nd ed. Lippincott Williams and Wilkins, London2011
        • Shirazu I.
        • Mensah Y.B.
        • Schandorf C.
        • Mensah S.Y.
        Determination of standard reference body indices for clinical application in Ghana.
        Int J Sci Technol Res. 2017; 6: 225-231
        • Pedersen C.C.E.
        • Hardy M.
        • Blankholm A.D.
        An evaluation of image acquisition techniques, radiographic practice, and technical quality in neonatal chest radiography.
        J Med Imaging Radiat Sci. 2018; 49: 257-264
        • NRPB
        Guidelines on Patient Dose to Promote the Optimisation of Protection for Diagnostic Medical Exposures: Documents of the NRPB 10(1).
        Chilton: National Radiological Protection Board. 1999; : 17-18
        • Wachabauer D.
        • Röthlin F.
        • Moshammer H.M.
        • Homolka P.
        Diagnostic Reference Levels for computed tomography in Austria: a 2018 nationwide survey on adult patients.
        Eur J Radiol. 2020; 125108863
      10. Javor A, Ferrari J, Posekany A, Asenbaum-Nan S. Stroke risk factors and treatment variables in rural and urban Austria: An analysis of the Austrian stroke unit registry. PLoS One 2019 10;14(4):e0214980. 10.1371/journal.pone.0214980.

      11. Sanuade OA, Dodoo FN, Koram K, de-Graft Aikins A. Prevalence and correlates of stroke among older adults in Ghana: Evidence from the Study on Global AGEing and adult health (SAGE). PLoS One 2019 13;14(3):e0212623. 10.1371/journal.pone.0212623.

        • Geryes B.H.
        • Hornbeck A.
        • Jarrige V.
        • Pierrat N.
        • Ducou Le Pointe H.
        • Dreuil S.
        Patient dose evaluation in computed tomography: a French national study based on clinical indications.
        Phys Med. 2019; 61
      12. Public Health England. National Diagnostic Reference Levels (NDRLs) Vol. 11, [Accessed 21 November 2016].

      13. Widmark A. Representative doses in Norway – 2017. Results from reporting and auditing and the establishment of new ones national reference values. Radiation Protection Report 2018: 3, Østerås: The Norwegian Radiation Protection Agency, Østerås; 2018.

        • Radiation and Nuclear Safety Authority
        Reference levels for patient radiation exposure in computed tomography examinations of adults.
        Radiation and Nuclear Safety Authority, Helsinki2013
        • Lee K.L.
        • Beveridge T.
        • Sanagou M.
        • Thomas P.
        Updated Australian diagnostic reference levels for adult CT.
        J Med Radiat Sci. 2020; 67: 5-15
        • Danish Health Authority
        CT Reference doser.
        Danish Health Authority, Copenhagen2015
        • Patschan D.
        • Buschmann I.
        • Ritter O.
        Contrast-induced nephropathy: update on the use of crystalloids and pharmacological measures.
        Int J Nephrol. 2018; 1: 1-8
        • Aberle C.
        • Ryckx N.
        • Treier R.
        • Schindera S.
        Update of national diagnostic reference levels for adult CT in Switzerland and assessment of radiation dose reduction since 2010.
        Eur Radiol. 2020; 30: 1690-1700
        • van der Molen A.J.
        • Schilham A.
        • Stoop P.
        • Prokop M.
        • Geleijns J.
        A national survey on radiation dose in CT in The Netherlands.
        Insights into Imaging. 2013; 4: 383-390
        • Weisenthal K.
        • Karthik P.
        • Shaw M.
        • Sengupta D.
        • Bhargavan-Chatfield M.
        • Burleson J.
        • et al.
        Evaluation of kidney stones with reduced-radiation dose CT: progress from 2011–2012 to 2015–2016-Not There Yet.
        Radiology. 2018; 286: 581-589
        • Schegerer A.A.
        • Nagel H.D.
        • Stamm G.
        • Adam G.
        • Brix G.
        Current CT practice in Germany: results and implications of a nationwide survey.
        Eur J Radiol. 2017; 90: 114-128
        • Foley S.J.
        • McEntee M.F.
        • Rainford L.A.
        Establishment of CT diagnostic reference levels in Ireland.
        Br J Radiol. 2012; 85: 1390-1397
        • Leithner R.
        • Homolka P.
        A quantitative comparison of data evaluation methods to derive diagnostic reference levels for CT from a dosimetric survey: correlation analysis compared to simple evaluation strategies.
        Phys Med. 2013; 29: 470-477
        • Salama D.H.
        • Vassileva J.
        • Mahdaly G.
        • Shawki M.
        • Salama A.
        • Gilley D.
        • et al.
        Establishing national diagnostic reference levels (DRLs) for computed tomography in Egypt.
        Phys Med. 2017; 39: 16-24
        • Gao Y.
        • Quinn B.
        • Pandit-Taskar N.
        • Behr G.
        • Mahmood U.
        • Long D.
        • et al.
        Patient-specific organ and effective dose estimates in pediatric oncology computed tomography.
        Phys Med. 2018; 45: 146-155
      14. Anim-Sampong S, Antwi WK, Botwe BO. Boateng SR. Comparison of 640-slice Aquilon ONE CT scanner’s measured dosimetric parameters with ICRP dose reference levels for head, chest and abdominal CT examinations. Saf Health 2, 7 (2016).