Diagnostic Reference Levels for Computed Tomography Examinations in Iran: A Nationwide Radiation Dose Survey

Document Type : Original Paper

Authors

1 Department of Radiology Technology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran

2 Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran

Abstract

Introduction: International Commission on Radiological Protection introduced three basic principles of radiation protection, namely justification, optimization, and dose limit. Medical exposure has no dose limits, and generally, diagnostic reference levels are used as a tool for optimization of patient protection.
Material and Methods: Dosimetry was performed on 20 CT scanners located in 14 cities in 12 provinces of Iran. A calibrated pencil-shaped ionization chamber, standard head and body CT dosimetry phantoms and a radiation monitor were used to determine and calculate Computed Tomography Dose Index (CTDI) and Dose Length Product (DLP). The DLP-based estimates of effective dose were derived using effective dose conversion coefficients.
Results: The nCTDIw values for head phantoms fell within the range of 22.05-168.38 and 43.77-426.69 µGy/mAs for 5 and 10mm slice thicknesses, respectively. These values for body phantom were 4.65-146.39 and 9.43-308.92 µGy/mAs for 5 and 10mm slice thicknesses, respectively. The third quartile of CTDIvol and DLP values for head CT examinations were 49.85 mGy and 1161.00 mGy-cm, respectively. The body CT examinations had the values of 8.89 mGy and 370.97 mGy-cm, respectively. The findings of this study revealed that the above-mentioned values can be considered as national diagnostic reference levels for head and body CT examinations in Iran.
Conclusion: The results of the current study suggested that there is a need to re-assess DRLs for CT examinations at regular time intervals by the appropriate regulatory authority which can improve the continuous performance of CT scanners in Iran.

Keywords

Main Subjects

References

  1. References

     

    1. Food U, Administration D. Initiative to reduce unnecessary radiation exposure from medical imaging. Center for Devices and Radiological Health. 2010.
    2. McNitt-Gray MF. AAPM/RSNA physics tutorial for residents: topics in CT: radiation dose in CT. Radiographics. 2002;22(6):1541-53.
    3. Din NNN, Zainon R, Rahman ATA. Evaluation of radiation dose in pediatric head CT examination: a phantom study. IOP Conference Series: Materials Science and Engineering. IOP Publishing. 2018.
    4. Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med. 2007;357(22):2277-84.
    5. Brenner DJ, Elliston CD, Hall EJ, Berdon WE. Estimated risks of radiation-induced fatal cancer from pediatric CT. American journal of roentgenology. 2001;176(2):289-96.
    6. International Commission on Radiological Protection Radiological protection in medicine. ICRP Publication 105. Ann ICRP. 2007;37:1–63.
    7. 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.
    8. Mourão AP, Alonso TC, DaSilva TA, editors. Study of the CT peripheral dose variation in a head phantom. Proceedings of the International Nuclear Atlantic Conference—INAC; 2009.
    9. FDA U. Performance standards for diagnostic x-ray systems. Fed. Regist. 1984; 49(171):646-51.
    10. Hill B, Venning AJ, Baldock C. A preliminary study of the novel application of normoxic polymer gel dosimeters for the measurement of CTDI on diagnostic x‐ray CT scanners. Med Phys. 2005;321589-97.
    11. Mortazavi S, Nouri M, Haghani M, Bahador A, Hashemi-Asl A. Should we be concerned about the population dose from computed tomography scans in Shiraz, Iran? Physica Medica: European Journal of Medical Physics. 2014;30: 55.
    12. Najafi M, Deevband MR, Ahmadi M, Kardan MR. Establishment of diagnostic reference levels for common multi-detector computed tomography examinations in Iran. Australas Phys Eng Sci Med. 2015;38(4):603-9.
    13. The Yearbook of 1382 . Department of Health Statistical Indices. Deputy of Treatment Affairs. Social Security Organization. 2003.
    14. European Commission. European guidelines on quality criteria for computed tomography. Report EUR 16262. 1999.
    15.  ImPACT and Medical Physics Department. CT scanner dose survey: measurement protocol. Version 5.0;  London .1997.
    16. Shrimpton P, Hillier M, Lewis M, Dunn M. Doses from computed tomography (CT) examinations in the UK-2003 review: NRPB Chilton; 2005.
    17. United Nation Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation. Report to the general assembly with scientific annexes . 2000.               
    18. Haddadi G, Mehdizadeh S, Haddadi MB, Meshkibaf MH. Evaluation of absorbed dose of critical organ in rando phantom under head, abdomen and pelvis spiral CT scan by thermo luminescent dosimetery-TLD. Journal of Fasa University of Medical Sciences. 2011;1(3):131-5.
    19. Matsunaga Y, Kawaguchi A, Kobayashi K, Kobayashi M, Asada Y, Minami K, et al. Effective radiation doses of CT examinations in Japan: a nationwide questionnaire-based study. The British journal of radiology. 2016;89(1058):20150671.
    20. Toori AJ, Shabestani-Monfared A, Deevband M, Abdi R, Nabahati M. Dose Assessment in Computed Tomography Examination and Establishment of Local Diagnostic Reference Levels in Mazandaran, Iran. Journal of biomedical physics & engineering. 2015;5(4):177.
    21. Tsai H, Tung C, Yu C, Tyan Y. Survey of computed tomography scanners in Taiwan: dose descriptors, dose guidance levels, and effective doses. Med Phys. 2007;34(4):1234-43.
    22. Al-Kinani A, Saddam A. Radiation Doses from Computed tomography in Iraq. Arab Journal of Nuclear Science and Applications. 2014;47(1):114-24.
    23. Wambani J, Korir G, Onditi E, Korir I. A survey of computed tomography imaging techniques and patient dose in Kenya. East Afr Med J. 2010;87(10).
    24. Mettler Jr FA, Thomadsen BR, Bhargavan M, Gilley DB, Gray JE, Lipoti JA, et al. Medical radiation exposure in the US in 2006: preliminary results. Health Phys. 2008;95(5):502-7.
    25. Foley SJ, McEntee MF, Rainford LA. Establishment of CT diagnostic reference levels in Ireland. The British journal of radiology. 2012;85(1018):1390-7.
    26. Tsapaki V, Aldrich JE, Sharma R, Staniszewska MA, Krisanachinda A, Rehani M, et al. Dose reduction in CT while maintaining diagnostic confidence: diagnostic reference levels at routine head, chest, and abdominal CT—IAEA-coordinated research project. Radiology. 2006;240(3):828-34.
    27. Afzalipour R, Rabi Mahdavi S, Khosravi H, Neshasteh-Riz A, Fatemeh Hosseini A. Evaluation of diagnostic reference dose levels in CT-scan examinations of adolescence in Tehran: a brief report. Tehran University Medical Journal. 2013;71(2).
    28. Parsi M, Sohrabi M, Mianji F, Paydar R. Determination of Examination-Specific Diagnostic Reference Level in Computed Tomography by A New Quality Control-Based Dose Survey Method. Health Phys. 2018;114(3):273-81.
    29. Sohrabi m, parsi m, mianji f. determination of national diagnostic reference levels in computed tomography examinations of iran by a new quality control-based dose survey method. radiation protection dosimetry. 2017:1-10.
    30. 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. Eur Radiol. 2008;18(9):1980-6.
    31. Takei Y, Miyazaki O, Matsubara K, Shimada Y, Muramatsu Y, Akahane K, et al. Nationwide survey of radiation exposure during pediatric computed tomography examinations and proposal of age-based diagnostic reference levels for Japan. Pediatr Radiol. 2016;46(2):280-5.
    32. Vassileva J, Rehani MM, Applegate K, Ahmed NA, Al-Dhuhli H, Al-Naemi HM. IAEA survey of paediatric computed tomography practice in 40 countries in Asia, Europe, Latin America and Africa: procedures and protocols. Eur Radiol. 2013;23(3):623-31.
    33. Muhogora W, Ahmed N, Alsuwaidi J, Beganovic A, Ciraj-Bjelac O, Gershan V, et al. Paediatric CT examinations in 19 developing countries: frequency and radiation dose. Radiation protection dosimetry. 2010;140(1):49-58.
    34. European Commission. European guidelines on quality criteria for Computed Tomography, EUR 16262 EN. Brussels: EC; 1999.
    35. Tsapaki V, Kottou S, Papadimitriou D. Application of European Commission reference dose levels in CT examinations in Crete, Greece. The British journal of radiology. 2001;74(885):836-40.
    36. Breiki G, Abbas Y, El-Ashry M, Diyab H. Evaluation of Radiation Dose and Image Quality for Patients Undergoing Computed Tomography (CT) Examinations. 2008.
    37. Al-Kinani A, Saddam A. Radiation Doses from Computed tomography in Iraq. Arab Journal of Nuclear Science and Applications. 2014;47(1):114-24.
    38. Ngaile JE, Msaki PK. Estimation of patient organ doses from CT examinations in Tanzania. J Appl Clin Med Phys. 2006;7(3):80-94.
    39. Shrimpton PC, Hillier MC, Lewis MA, Dunn M. Doses from computed tomography (CT) examinations in the UK-2003 review. Chilton: NRPB; 2005.
    40. Hayton A, Wallace A, Marks P, Edmonds K, Tingey D, Johnston P. Australian diagnostic reference levels for multi detector computed tomography. Australas Phys Eng Sci Med. 2013;36(1):19-26.
    41. Saravanakumar A, Vaideki K, Govindarajan K, Jayakumar S. Establishment of diagnostic reference levels in computed tomography for select procedures in Pudhuchery, India. Journal of medical physics/Association of Medical Physicists of India. 2014;39(1):50.
    42. 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. J Radiol Prot. 2018;38(2):525.

     

     

     

     

     

     

Iranian Journal of Medical Physics
Volume 16, Issue 1 - Serial Number 1
January and February 2019
Pages 19-26

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History

  • Receive Date: 30 June 2018
  • Revise Date: 11 September 2018
  • Accept Date: 11 September 2018

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