Risks associated to ionising radiation from medical imaging techniques have focused the attention of the medical society and general population. This risk is aimed to determine the probability that a tumour is induced as a result of a computed tomography (CT) examination since it makes nowadays the biggest contribution to the collective dose. Several models of cancer induction have been reported in the literature, with diametrically different implications. This article reviews those models, focusing on the ones used by the scientific community to estimate CT detriments. Current estimates of the probability that a CT examination induces cancer are reported, highlighting its low magnitude (near the background level) and large sources of uncertainty. From this objective review, it is concluded that epidemiological data with more accurate dosimetric estimates are needed. Prediction of the number of tumours that will be induced in population exposed to ionising radiation should be avoided or, if given, it should be accompanied by a realistic evaluation of its uncertainty and of the advantages of CTs. Otherwise they may have a negative impact in both the medical community and the patients. Reducing doses even more is not justified if that compromises clinical image quality in a necessary investigation.
• Predictions of radiation-induced cancer should be discussed alongside benefits of imaging.
• Estimates of induced cancers have noticeable uncertainties that should always be highlighted.
• There is controversy about the acceptance of the linear no-threshold model.
• Estimated extra risks of cancer are close to the background level.
• Patients should not be alarmed by potential cancer induction by CT examinations.
Sodickson A (2012) Strategies for reducing radiation exposure in multi-detector row CT. Radiol Clin North Am 50:1–14PubMedCrossRefGoogle Scholar
Teeuwisse W, Geleijns J, Veldkamp W (2007) An inter-hospital comparison of patient dose based on clinical indications. Eur Radiol 17:1795–1805PubMedCrossRefGoogle Scholar
United Nations Scientific Committee on the Effects of Atomic Radiation (2000) UNSCEAR 2000 Report. Sources and effects of ionizing radiation. United Nations, New YorkGoogle Scholar
National Council on Radiation Protection and Measurements (2001) NCRP Report 136. Evaluation of the linear nonthreshold dose–response model for ionizing radiation. NCRP, BethesdaGoogle Scholar
Hall EJ, Henry S (2004) Kaplan Distinguished Scientist Award 2003: the crooked shall be made straight; dose–response relationships for carcinogenesis. Int J Radiat Biol 80:327–337PubMedCrossRefGoogle Scholar
Wall BF, Kendall GM, Edwards AA, Bouffler S, Muirhead CR, Meara JR (2006) What are the risks from medical X-rays and other low dose radiation? Br J Radiol 69:285–294CrossRefGoogle Scholar
BEIR VII (2006) Health risks from exposure to low levels of ionizing radiation. BEIR VII Phase 2. The National Academies Press, WashingtonGoogle Scholar
Xu XG, Bednarz B, Paganetti H (2008) A review of dosimetry studies on external-beam radiation treatment with respect to second cancer induction. Phys Med Biol 53:R193–R241PubMedCrossRefGoogle Scholar
United Nations Scientific Committee on the Effects of Atomic Radiation (1994) UNSCEAR 1994 Report to the General Assembly. Annex B. Adaptive responses to radiation in cells and organisms. United Nations, New YorkGoogle Scholar
Pierce DA, Preston DL (2000) Radiation-related cancer risks at low doses among atomic bomb survivors. Radiat Res 154:178–186PubMedCrossRefGoogle Scholar
Pauwels EK, Bourguignon M (2011) Cancer induction caused by radiation due to computed tomography: a critical note. Acta Radiol 52:767–773PubMedCrossRefGoogle Scholar
Brenner DJ, Sachs RK (2006) Estimating radiation-induced cancer risks at very low doses: rationale for using a linear no-threshold approach. Radiat Environ Biophys 44:253–256PubMedCrossRefGoogle Scholar
Tubiana M (2005) Dose-effect relationships and estimation of the carcinogenic effects of low doses of ionizing radiation: the joint report of the Académie des Sciences (Paris) and of the Académie Nationale de Médecine. Int J Radiat Oncol Biol Phys 63:317–319PubMedCrossRefGoogle Scholar
Tubiana M, Aurengo A, Averbeck D, Masse R (2006) Recent reports on the effect of low doses of ionizing radiation and its dose-effect relationship. Radiat Environ Biophys 44:245–251PubMedCrossRefGoogle Scholar
Pierce DA, Shimizu Y, Preston DL et al (1996) Studies of the mortality of atomic bomb survivors. Report 12, part 1. Cancer: 1950–1990. Radiat Res 146:1–27PubMedCrossRefGoogle Scholar
Brenner DJ (2002) Estimating cancer risks from pediatric CT: going from the qualitative to the quantitative. Pediatr Radiol 32:228–231PubMedCrossRefGoogle Scholar
Samei E, Li X, Chen B, Reiman R (2013) The effect of dose heterogeneity on radiation risk in medical imaging. Radiat Prot Dosimetry 155:42–58PubMedCrossRefGoogle Scholar
Health Protection Agency (2011) Radiation risks from medical x-ray examinations as a function of the age and sex of the patient. HPA-CRCE-028. Health Protection Agency, DidcotGoogle Scholar
Calandrino R, Ardu V, Corletto D et al (2012) Evaluation of second cancer induction risk by CT follow-up in oncological long-surviving patients. Health Phys Soc 104:1–8CrossRefGoogle Scholar
Ivanov VK, Tsyb AF, Mettler FA, Menyaylo AN, Kashcheev VV (2012) Methodology for estimating cancer risks of diagnostic medical exposure: with an example of risks associated with computed tomography. Health Phys 103:732–739PubMedCrossRefGoogle Scholar
Ivanov VK, Kashcheev VV, Chekin SY et al (2013) Estimation of risk from medical radiation exposure based on effective and organ dose: how much difference is there? Radiat Prot Dosimetry 155:317–328PubMedCrossRefGoogle Scholar
Brenner DJ, Elliston CD, Hall EJ, Berdon WE (2001) Estimated risks of radiation-induced fatal cancer from pediatric CT. AJR Am J Roentgenol 176:289–296PubMedCrossRefGoogle Scholar
Berrington de Gonzalez A, Apostoaei AI, Veiga LH et al (2012) RadRAT: a radiation risk assessment tool for lifetime cancer risk projection. J Radiol Prot 32:205–222PubMedCrossRefGoogle Scholar
Miglioretti DL, Johnson E, Williams A et al (2013) The use of computed tomography in pediatrics and the associated radiation exposure and estimated cancer risk. JAMA Pediatr E1-E8Google Scholar
Perisinakis K, Seimenis I, Tzedakis A et al (2012) Triple-rule-out computed tomography angiography with 256-slice computed tomography scanners: patient-specific assessment of radiation burden and associated cancer risk. Invest Radiol 47:109–115PubMedCrossRefGoogle Scholar
Health Physics Society (2004) Radiation risk in perspective. Position Statement of the Health Physics Society: PS010-PS011Google Scholar
Pearce MS, Salotti JA, Little MP et al (2012) Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study. Lancet 380:499–505PubMedCentralPubMedCrossRefGoogle Scholar
Kim KP, Berrington de González A, Pearce MS et al (2012) Development of a database of organ doses for paediatric and young adult CT scans in the United Kingdom. Radiat Prot Dosimetry 150:415–426PubMedCrossRefGoogle Scholar
United Nations Scientific Committee on the Effects of Atomic Radiation (2010) UNSCEAR 2008 report to the general assembly. United Nations, New YorkGoogle Scholar
Ron E, Modan B, Boice JD Jr et al (1988) Tumors of the brain and nervous system after radiotherapy in childhood. N Engl J Med 319:1033–1039PubMedCrossRefGoogle Scholar
Preston DL, Kusumi S, Tomonaga M et al (1994) Cancer incidence in atomic bomb survivors. III. Leukemia, lymphoma and multiple myeloma. Radiat Res 137:1950–1987CrossRefGoogle Scholar
Mathews JD, Forsythe AV, Brady Z et al (2013) Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians. BMJ 346:f2360PubMedCentralPubMedCrossRefGoogle Scholar
Baysson H, Etard C, Brisse HJ, Bernier MO (2012) Diagnostic radiation exposure in children and cancer risk: current knowledge and perspectives. Arch Pediatr 19:64–73PubMedCrossRefGoogle Scholar
Krille L, Jahnen A, Mildenberger P et al (2011) Computed tomography in children: multicenter cohort study design for the evaluation of cancer risk. Eur J Epidemiol 26:249–250PubMedCrossRefGoogle Scholar
Krille L, Zeeb H, Jahnen A et al (2012) Computed tomographies and cancer risk in children: a literature overview of CT practices, risk estimations and an epidemiologic cohort study proposal. Radiat Environ Biophys 51:103–111PubMedCrossRefGoogle Scholar
Epidemiological study to quantify risks for paediatric computerized tomography and to optimise doses. Available via: epi-ct.iarc.fr. Last accessed 26 June 2013Google Scholar
Smith-Bindman R, Lipson J, Marcus R et al (2009) Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer. Arch Intern Med 169:2078–2086PubMedCrossRefGoogle Scholar
United Nations Scientific Committee on the Effects of Atomic Radiation (2012) Report of the UNSCEAR. 59th session. May 21–25. General Assembly Official Records. 67th session, Supplement No. 46. United Nations, New YorkGoogle Scholar
Brix G, Nissen-Meyer S, Lechel U et al (2009) Radiation exposures of cancer patients from medical X-rays: how relevant are they for individual patients and population exposure? Eur J Radiol 72:342–347PubMedCrossRefGoogle Scholar
Eschner W, Schmidt M, Dietlein M et al (2010) PROLARA: prognosis-based lifetime attributable risk approximation for cancer from diagnostic radiation exposure. Eur J Nucl Med Mol Imaging 37:131–135PubMedCrossRefGoogle Scholar
Eisenberg JD, Harvey HB, Moore DA et al (2012) Falling prey to the sunk cost bias: a potential harm of patient radiation dose histories. Radiology 263:626–628PubMedCrossRefGoogle Scholar
Hendee WR, O’Connor MK (2012) Radiation risks of medical imaging: separating fact from fantasy. Radiology 264:312–321PubMedCrossRefGoogle Scholar
Recchia V, Dodaro A, Braga L (2013) Event-based versus process-based informed consent to address scientific evidence and uncertainties in ionising medical imaging. Insights Imaging 4:647–653PubMedCentralPubMedCrossRefGoogle Scholar