Document Type : Original Article(s)


1 Department of Radiology Technology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran

2 Department of Nuclear Physics, Bu-Ali Sina University, Hamadan, Iran



Background: The breast, being a highly radiosensitive organ, is exposed to scattered radiation during brain computed tomography (CT) scans. This study aims to estimate the lifetime attributable risk (LAR) of female breast cancer resulting from brain CT scans.
Method: 90 women participated in this cross-sectional study. The LAR of breast cancer incidence was estimated based on health risks associated with exposure to low levels of ionizing radiation, as per the BEIR VII Phase 2 guidelines. The absorbed dose to the breasts was measured using thermoluminescence dosimeters, and the effective dose was calculated from the dose length product. All brain CT scans were conducted using a 16-slice scanner (SOMATOM EMOTION). Statistical analysis involved the Mann-Whitney test to compare the means of breast dose, effective dose, and LAR at a significance level of 0.05.
Results: The mean age of the participants was 40 ± 22 years, with an age range of 10 to 83 years. The average dose to the breasts without and with shielding was 0.26 ± 0.19 mGy and 0.096 ± 0.13 mGy, respectively (P < 0.05). The effective dose was 0.85 ± 0.35 mSv without shielding and 0.79 ± 0.32 mSv with shielding (P = 0.539). The maximum LAR was 5.41 cases per 100,000 persons aged 10-15 years without shielding. The average LARs were 1.16 and 0.41 breast cancer incidences per 100,000 persons with and without shielding, respectively (P < 0.05).
Conclusion: The LAR of breast cancer in brain CT scans is significant and should not be overlooked. The use of breast shielding can substantially reduce this risk. Therefore, it is recommended to employ radioprotective shields to cover the breasts during this type of scan.


Salman Jafari (Google Scholar)


Main Subjects

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination, and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.30476/mejc.2023.98809.1919

  1. Omidvari S, Eskandari Z, Nasrollahi H, Ahmadloo N, Ansari M, Hamedi SH, et al. The investigation of prophylactic effect of StrataXRT gel on radiation-induced dermatitis in breast cancer patients: a randomized clinical trial. Middle East J Cancer. 2022;13(2):293-8. doi: 10.30476/mejc.2021.86775.1372.
  2. World Health Organization International Agency for Research on Cancer (IARC). [Internet] GLOBOCAN 2020: Islamic Republic of Iran; 2021 [cited at: 2021 March]. Available from:
  3. Carmichael A, Sami A, Dixon J. Breast cancer risk among the survivors of atomic bomb and patients exposed to therapeutic ionising radiation. Eur J Surg Oncol. 2003;29(5):475-9. doi: 10.1016/S0748-7983(03)00010-6.
  4. Yilmaz MH, Albayram S, Yasar D, Özer H, Adaletli I, Selçuk D, et al. Female breast radiation exposure during thorax multidetector computed tomograph.y and the effectiveness of bismuth breast shield to reduce breast radiation dose. J Comput Assist Tomogr. 2007;31(1):138-42. doi: 10.1097/01.rct.0000235070.50055.e6.
  5. Elshami W, Tekin HO, Issa SA, Abuzaid MM, Zakaly HM, Issa B, et al. Impact of eye and breast shielding on organ doses during cervical spine radiography: design and validation of MIRD computational phantom. Front Public Health. 2021;9:751577. doi: 10.3389/fpubh.2021.751577.
  6. Tahmasebzadeh A, Paydar R, Kaeidi H. Lifetime attributable breast cancer risk related to lung CT scan in women with Covid19. Front Biomed Technol. 2023;11(2): in press.
  7. Kwan AC, Pourmorteza A, Stutman D, Bluemke DA, Lima JA. Next-generation hardware advances in CT: cardiac applications. Radiology. 2021;298:3-17. doi: 10.1148/radiol.2020192791.
  8. Colang JE, Killion JB, Vano E. Patient dose from CT: a literature review. Radiol Technol. 2007;79(1):17-26.
  9. Wiest PW, Locken JA, Heintz PH, Mettler FA Jr. CT scanning: a major source of radiation exposure. Semin Ultrasound CT MR. 2002;23(5):402-10. doi: 10.1016/s0887-2171(02)90011-9.
  10. Tavakoli MB, Jabbari K, Jafari S, Hashemi SM, Akbari M. Evaluating the absorbed dose of skin, thyroid and eye in coronary angiography ct imaging and its comparison with conventional angiography. [In Persian] J Isfahan Med Sch. 2011;29(159):1703-12.
  11. Tavakoli H M, Jabari K, Salman J. SU-E-I-51: Investigation of absorbed dose to the skin, eyes and thyroid of patients during CT angiography and comparison with conventional angiography. Med Phys. 2012;39(6Part4):3636. doi: 10.1118/1.4734767.
  12. Tavakoli MB, Faraji R, Sajjadieh A, Jafari S. Determination of the weighted computed tomography dose index in coronary multidetector computed tomography angiography. [In Persian] J Isfahan Med Sch. 2016;34(398):1060-5.
  13. Kular S, Martin A. A primer in interpretation of head CT scans. Br J Hosp Med (Lond). 2019;80(11):C156-C161.doi: 10.12968/hmed.2019.80.11.C156.
  14. Vilela P, Rowley HA. Brain ischemia: CT and MRI techniques in acute ischemic stroke. Eur J Radiol. 2017:96:162-72.doi: 10.1016/j.ejrad.2017.08.014.
  15. Hsieh J. Computed tomography: principles, design, artifacts, and recent advances. 3rd ed. Washington: SPIE Press Book; 2022.786p.
  16. Hamberg LM, Rhea JT, Hunter GJ, Thrall JH. Multi–detector row CT: radiation dose characteristics. Radiology. 2003;226(3):762-72.doi: 10.1148/radiol.2263020205.
  17. Thornton FJ, Paulson EK, Yoshizumi TT, Frush DP, Nelson RC. Single versus multi–detector row CT: comparison of radiation doses and dose profiles. Acad Radiol. 2003;10(4):379-85.doi: 10.1016/s1076-6332(03)80026-0.
  18. Wedegärtner U, Thurmann H, Schmidt R, Adam G. Radiation exposure of the head, midface and pelvis in multi-slice CT (MSCT): comparison with single-slice CT (SSCT). Rofo. 2003;175(2):234-8.doi: 10.1055/s-2003-37242.
  19. Jaffe TA, Hoang JK, Yoshizumi TT, Toncheva G, Lowry C, Ravin C. Radiation dose for routine clinical adult brain CT: variability on different scanners at one institution. AJR Am J Roentgenol. 2010;195(2):433-8.doi: 10.2214/AJR.09.3957.
  20. Manglona PB, Cadeliña LG, Baclig A, Johnson S, Mercado S. [P122] Assessment of scattered radiation in computed tomography (CT) facilities with multi-slice ct machines. Phys Med. 2018;52:135. doi: 10.1016/j.ejmp.2018.06.435.
  21. Brnić Z, Vekić B, Hebrang A, Anić P. Efficacy of breast shielding during CT of the head. Eur Radiol. 2003;13(11):2436-40.doi: 10.1007/s00330-003-1945-1.
  22. Mazonakis M, Tzedakis A, Damilakis J, Gourtsoyiannis N. Thyroid dose from common head and neck CT examinations in children: is there an excess risk for thyroid cancer induction? Eur Radiol. 2007;17(5):1352-7.doi: 10.1007/s00330-006-0417-9.
  23. Zalokar N, Mekis N. Efficacy of breast shielding during head computed tomography examination. Radiol Oncol. 2021;55:116-20. doi: 10.2478/raon-2020-0044.
  24. Jansen-van der Weide MC, Greuter MJ, Jansen L, Oosterwijk JC, Pijnappel RM, de Bock GH. Exposure to low-dose radiation and the risk of breast cancer among women with a familial or genetic predisposition: a meta-analysis. Eur Radiol. 2010;20(11):2547-56.doi: 10.1007/s00330-010-1839-y.
  25. Frane N, Bitterman A. Radiation Safety and Protection. 2023 May 22. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 32491431.
  26. Lara A, Osorio M, Olvera B, Villafañez Y, García R, Rivera T. Importance of patient radiation protection in computed tomography procedures. J Phys.: Conference Series 2019;1221: 012065. doi: 10.1088/1742-6596/1221/1/012065.
  27. Fordham LA, Brown ED, Washburn D, Clark RL. Efficacy and feasibility of breast shielding during abdominal fluoroscopic examinations. Acad Radiol. 1997;4(9):639-43. doi: 10.1016/s1076-6332(05)80269-7.
  28. Sadeghi M, Sina S, Faghihi R. Investigation of Lif, mg and Ti (TLD-100) reproducibility. J Biomed Phys Eng. 2015;5(4):217-22.
  29. Attix FH. Introduction to radiological physics and radiation dosimetry. 2nd ed. Weinheim: Wiley-VCH; 2004. 607p.
  30. National Research Council. 2006. Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. Washington, DC: The National Academies Press.
  31. Jamshidi MH, Karami A, Ordoni J, Bijari S. Estimation of lifetime attributable risk (LAR) of cancer associated with chest computed tomography procedures in children. Front Biomed Technol. 2023;10(4):441-8. doi:10.18502/fbt.v10i4.13726.
  32. Afzalipour R, Abdollahi H, Hajializadeh M, Jafari S, Mahdavi SR. Estimation of diagnostic reference levels for children computed tomography: A study in Tehran, Iran. Int J Radiat. 2019;17:407-13. doi: 10.18869/acadpub.ijrr.17.3.15.
  33. Jafari S, Ghazikhanlu Sani K, Karimi M, Khosravi H, Goodarzi R, Pourkaveh M. Establishment of diagnostic reference levels for computed tomography scanning in Hamadan. J Biomed Phys Eng. 2020;10(6):792-800. doi: 10.31661/jbpe.v0i0.2004-1099.
  34. Yang CC. Evaluation of impact of factors affecting CT radiation dose for optimizing patient dose levels. Diagnostics (Basel). 2020;10(10):787. doi: 10.3390/diagnostics10100787.
  35. Mahesh M. The essential physics of medical imaging. Med Phys. 2013;40(7).doi: 10.1118/1.4811156.
  36. Mahesh M. MDCT physics: the basics: technology, image quality and radiation dose. In Shaw R, editor. 1st ed. Philadelphia : Lippincott Williams & Wilkins; 2009.196p.
  37. Söderberg M. Overview, practical tips and potential pitfalls of using automatic exposure control in CT: Siemens CARE Dose 4D. Radiat Prot Dosimetry. 2016;169(1-4):84-91.doi: 10.1093/rpd/ncv459.
  38. Beaconsfield T, Nicholson R, Thornton A, Al-Kutoubi A. Would thyroid and breast shielding be beneficial in CT of the head? Eur Radiol. 1998;8(4):664-7.doi: 10.1007/s003300050456.
  39. Vafaei A, Khosravi N, Shojaei Barjouei N, Gholizadeh Sendani N, Oloumi Sadeghi A, Shams Akhtari A. Radiation organ dose measurement and cancer risk estimation in CT examination on trauma patients. Middle East J Cancer. 2019;10(3):206-13. doi: 10.30476/mejc.2019.82391.1086.