Local Diagnostic Reference Levels for Common Computed Tomography Procedures at a Tertiary Hospital in South Africa

Document Type : Original Paper

Authors

Department of Medical Physics, Faculty of Health Sciences, Sefako Makgatho Health Sciences University, Ga-Rankuwa, South Africa

Abstract

Introduction: An operational computed tomography (CT) scanner is a major source of human exposure to ionizing radiation. Exposure increases the risk of cancer and aplastic anaemia. All radiation exposures should be justified and optimized to meet the clinical objective. In order to avoid the administration of excessive radiation dose to patients, diagnostic reference levels (DRLs) were proposed. The DRLs identify unusually high radiation doses during CT procedures, which are not commensurate with the clinical objective. They have been successfully implemented in Europe, United States, some developed countries, and a few developing countries. In this regard, the present study aimed at establishing DRLs for the head, chest, and abdomen/pelvis CT procedures at a tertiary hospital in South Africa.
Material and Methods: A retrospective analysis of volume CT dose index (CTDIvol) and dose length product (DLP) was performed on 100 randomly selected adult patients for each of the head, chest, and abdomen/pelvis CT procedures. The mean values of the DLP and CTDIvol dose parameters were calculated using SPSS, version 24.  
Results: The established DRLs for CTDIvol were 32; 7, and 32 mGy for the head, abdomen/pelvis, and chest, respectively, while the DLPs for the respective protocols were 767, 386, and 593 mGy.cm.
Conclusion: The implementation of DRLs facilitates identifying CT doses that are not commensurate with the clinical objective, thereby lowering patients’ doses significantly. 

Keywords

Main Subjects


  1.  

    1. Liang CR, Chen PX, Kapur J, Ong MK, Quek ST, Kapur SC. Establishment of institutional diagnostic reference levels for computed tomography with automated dose-tracking software. J Med Radiat Sci. 2017; 64:82-9.
    2. Saravanakumar A, Vaideki K, Govindarajan KN, Jaykumar S. Establishment of diagnostic reference levels in computed tomography for select procedures in Pudhuchery, India. J Med Phys. 2014; 39(1):50-6.
    3. Brenner DJ, Hall EJ. Computed Tomography – An increasing source of Radiation Exposure. N Engl J Med. 2007; 357:2277-84.
    4. Golding SJ, Shrimpton PC, Radiation dose in CT: are we meeting the challenge? The Bri J Radiol. 2002;75(889):1-4. DOI: 101259/bjr.75889.750001.                                                                                                                                                                     
    5. Huda W, Mettler F. Volume CT Dose Index and Dose-Length Product Displayed during CT. What Good Are They? Radiology. 2011; 258(1):236-42.
    6. Bahreyni Toossi MT, Bahrami M. Assessment of Patient Dose from CT Examinations in Khorasan, Iran. Iran J Med Phys. 2012; 9(4):233-8.
    7. Kanal KM, Butler PF, Sengupta D, Bhargavan-Chatfield M, Coombs LP, Morin RL. U.S. Diagnostic Reference Levels and Achievable Doses f or 10 Adult CT Examination. Radiology. 2017; 284:120-33.
    8. Meyer S, Groenewald WA, Pitcher RD. Diagnostic reference levels in low- and middle-income countries: early ‘‘ALARAm’’ bells? Acta Radiologica. 2017; 58(4):442-8.
    9. Esen Nsikan U, Obed, R. Assessment of Patients’ Entrance Skin Dose from Diagnostic X-ray Examinations at Public Hospitals of Akwa Ibom State, Nigeria. Iranian Journal of Medical Physics. 2015; 12(2):93-100.
    10. Nyathi M. Quantitative evaluation of parotid and submandibular salivary glands function post radiation therapy of head and neck tumours. PhD thesis. Sefako Makgatho Health Sciences University. Ga-Rankuwa. South Africa. 2016.
    11. Zarghani H, Bahreyni Toossi MT. Evaluation of Organ and Effective Doses to Patients Arising from Some Common X-Ray Examinations by PCXMC Program in Sabzevar. Iran J Med Phys. 2015; 12(4): 284-91.
    12. Zarghani H, Bahreyni Toossi MT. Local Diagnostic Reference Levels for Some Common Diagnostic X-Ray Examinations In Sabzevar County of Iran. Iran J Med Phys. 2018; 15:62-5.
    13. ICRP.1990 Recommendations of the International Commission of Radiological Protection. ICRP Publication 60.Ann ICRP. 1991; 21(1-3).
    14. Radiological protection and safety in medicine. A report of the International Commission on Radiological Protection. Ann ICRP. 1996; 26(2):1-47 [Corrected version: Ann ICRP 1997; 27(2):61].
    15. Oresegu M, Rehani MM. Optimization of the radiological protection of patients undergoing radiography, fluoroscopy and computed tomography. IAEA-TECDOC-1423. Vienna. 2004.
    16.  McCollough C, Branham T, Herlihy V, Zeman R. Diagnostic Reference Levels From the ACR CT Accreditation Program. JACR. 2011; 8(11): 795-803.
    17. ICRP, Radiological Protection and Safety in Medicine. ICRP Publication 73. Ann. ICRP 26 (2) .1996.                                                                                                                                                                                
    18. American College of Radiology. ACR practice guideline for diagnostic reference levels in medical x-ray imaging. In: American College of Radiology. Practice guidelines and technical standards. Reston, Va: American College of Radiology; 2002:1– 6.                                                                                                                                                                                                                  
    19. American College of Radiology. Practice and guideline for diagnostic reference levels in Medical X-ray Imaging. Available from: http://www.ncradiation.net/Xray/documents/acrreflevelsfluoro.pdf                                                                                                                                                                                   
    20. Kanal KM, Butler PF, Sengupta D, Bhargavan-Chatfield M, Coombs LP, Morin RL. U.S. Diagnostic Reference Levels and Achievable Doses f or 10 Adult CT Examination. Radiology. 2017; 284:120-33.
    21. McCollough C, Branham T, Herlihy V, Bhargavan M, Robbins L, Bush K , et al. Diagnostic Reference Levels from the ACR CT Accreditation Program. J Am Coll Radiol. 2011; 8: 793-5.
    22. Saravanakumar A, Vaideki K, Govindarajan KN, Jayakumar S. Establishment of diagnostic reference levels in computed tomography for select procedures in Pudhuchery, India. J Med Phys. 2014. 39(1):50-5.
    23. Foley JS, Mcentee MF, Rainford LA. Establishment of CT diagnostic reference levels in Ireland. Brit J Radiol. 2012; 85:1390-97.
    24. Salama DH, Vassileva J, Mahdaly , Shawki M, Salama A, Gilley D, et al. Establishment of national diagnostic reference level for computed tomography in Egypt. Physica medica. 2017; 39: 16-24.
    25. Palorini F, Origgi D, Granata C , Matranga D, Salerno S. Adult exposure from MDCT including multiphase studies: first Italian nationwide survey. Eur Radiol. 2013; 24(2):469-83. DOI: 10.1007/s00330-013-3031-7.
    26. Radiological protection and safety in medicine. A report of the International Commission on Radiological Protection. Ann ICRP. 1996; 26(2):1-47. [Corrected version: Ann ICRP. 1997; 27(2):61].
    27. Shrimpton PC, Hillier MC, Meeson S, Golding SJ. Doses from Computed Tomography (CT) Examinations in the UK – 2011 Review. Oxfordshire. England.  2014.
    28. ICRP. Application of the Commission's Recommendations for the Protection of People in Emergency Exposure Situations. ICRP Publication 109. Ann. ICRP 39. 2009.
    29. Ekpo EU, Adejoh T, Akwo JD, Emeka OC, Modu AA, Abba M, et al. Diagnostic reference levels for common computed tomography (CT) examinations. J. Radiol Prot. 2018. 38: 525-35.
    30.  
    31. Nei P, Li H, Duan Y, Wang X, Ji X, Cheng Z, Wang A, et al. Impact of sonogram affirmed iterative reconstruction (SAFIRE) algorithm on image quality with 70 kVp-Tube voltage dual-source CT angiography in children with congenital heart disease. Plos ONE. 2014; 9: e91123.
    32. Han BK, Grant KL, Sedlmair M, Lindeberg J, Lesser JR. Assessment of an iterative reconstruction algorithm (SAFIRE) on image quality in paediatric cardiac CT datasets. 2012. J Cardiovascular Computed Tomography. 2012; 6: 200-4.
    33. Sahknini L. CT radiation dose optimization and reduction for routine head, chest and abdominal CT examination. Radiol.   Diagn Imaging. 2017; 2(1): 1-4.
    34. Ngaile JE, Msaki P, Kazema R. Towards establishment of the national dose reference levels from computed from computed tomography examinations in Tanzania. J. Radiol. Prot. 2006; 26: 213-25.
    35. Ekpo EU, Adejoh T, Akwo JD, et al. Diagnostic reference levels for common computed tomography (CT) examinations. J. Radiol Prot. 2018. 38: 525-35.
    36. Tavakoli MB, Heydari K, Jafari S. Evaluation of Diagnostic Reference Levels for CT scan in Isfahan. Global Journal of Medicine Researches and Studies. 2014; 1(4): 130-4.