Picano et al. BMC Cancer 2012, 12:157 http://www.biomedcentral.com/1471-2407/12/157 damage is now considered proven with epidemiological evidences for doses > 500 mSv. The head doses involved in radiotherapy are high, usually above 2 Sv, whereas the low-dose range of professional exposure typically involves lifetime cumulative whole-body exposure in the low-dose range of < 200 mSv, but with head exposure which may (in absence of protection) arrive at a head equivalent dose of 1 to 3 Sv after a professional lifetime (corresponding to a brain equivalent dose around 500 mSv). At this point, a systematic assessment of brain (cancer and non-cancer) effects of chronic low-dose radi- ation exposure in interventional cardiologists and staff is needed. Abbreviations CNS: Central nervous system; DG: Dentate gyrus; ICRP: International Commission of Radiological Protection; LDR: Low dose radiation; SGZ: Sub-granular zone; UNSCEAR: United Nations Scientific Committee on the Effects of Atomic Radiation. Competing interests The authors declare that they have no competing interests. Acknowledgements This work received financial support from the Italian Ministry of Health (Strategic Project 2010, Istituto Superiore di Sanità: Health and Safety in the Workplace). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Authors’ contributions EP is a clinical cardiologist and drafted the manuscript; all authors critically revised it and gave a critical intellectual contribution. In particular, EV is a medical physicist, who reviewed and contributed to writing the radiation exposure section; LD is a neurobiologist, who reviewed and contributed to writing the part on cognitive effects; MB is a statistician and epidemiologist, who reviewed and contributed to writing the part on brain cancer; ITC is a radiation physicist, who reviewed and contributed to writing the parts on radiation exposure and cancer. All authors read and approved the final version for submission. Author details 1Institute Clinical Physiology of the National Research Council CNR, 56124 Pisa, Italy. 2San Carlos University Hospital, Complutense University, Medical Physics Service, Madrid, Spain. 3Neuroscience Institute of the National Research Council, CNR, Pisa, and Scienze e Tecnologie Biomediche Department, L'Aquila University, Pisa, Italy. 4Institute of Environmental Medicine, Karolinska Institutet, Karolinska, Sweden. 5Environment and Radiation, International Agency for Research on Cancer, Lyon, France. Received: 2 January 2012 Accepted: 27 April 2012 Published: 27 April 2012 References 1. UNSCEAR: Sources and effects of ionizing radiation. In United Nations Scientific Committee on the Effects of Atomic Radiation, 2008. 2. BEIR VII Phase 2: Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation; Nuclear and Radiation Studies Board, Division on Earth and Life Studies, National Research Council of the National Academies. Health Risks From Exposure to Low Levels of Ionizing Radiation. Washington: The National Academies Press; 2006. 3. Annals of the ICRP: Early and late effects of radiation in normal tissues and organs: threshold doses for tissue reactions and other non-cancer effects of radiation in a radiation protection context.: public draft; 2012. published at ICRP website: www.icrp.org. 4. Vañó E, González L, Guibelalde E, Fernández JM, Ten JI: Radiation exposure to medical staff in interventional and cardiac radiology. Br J Radiol 1998, 71:954–960. Page 11 of 13 5. Lie , Paulsen GU, Wøhni T: Assessment of effective dose and dose to the lens of the eye for the interventional cardiologist. Radiat Prot Dosimetry 2008, 132:313–318. 6. Kuon E: Radiation exposure in invasive cardiology. Heart 2008, 94:667–674. 7. ICRP’s: Recommendations on Radiological Protection Issue n. 136, 2007. http://www.icrp.org. 8. Darby SC, Cutter DJ, Boerma M, Constine LS, Fajardo LF, Kodama K, Mabuchi K, Marks LB, Mettler FA, Pierce LJ, Trott KR, Yeh ET, Shore RE: Radiation-related heart disease: current knowledge and future prospects. Int J Radiat Oncol Biol Phys 2010, 76:656–665. 9. ICRP Statement on Tissue Reactions: Approved by the Commission on April 21, 2011; 2011. www.icrp.org/docs/ICRP%20Statement%20on%20Tissue%20Reactions. 10. Picano E: Sustainability of medical imaging. Education and debate. BMJ 2004, 328:578–580. 11. Mettler FA Jr, Bhargavan M, Faulkner K, Gilley DB, Gray JE, Ibbott GS, Lipoti JA, Mahesh M, McCrohan JL, Stabin MG, Thomadsen BR, Yoshizumi TT: Radiologic and nuclear medicine studies in the United States and worldwide: frequency, radiation dose, and comparison with other radiation sources–1950–2007. Radiology 2009, 253:520–531. 12. Gerber TC, Carr JJ, Arai AE, Dixon RL, Ferrari VA, Gomes AS, Heller GV, McCollough CH, McNitt-Gray MF, Mettler FA, Mieres JH, Morin RL, Yester MV: Ionizing radiation in cardiac imaging: a science advisory from the American Heart Association Committee on Cardiac Imaging of the Council on Clinical Cardiology and Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention. Circulation 2009, 119:1056–1065. 13. Vano E: Radiation exposure to cardiologists: how it could be reduced. Heart 2003, 89:1123–1124. 14. Kim KP, Miller DL, Balter S, Kleinerman RA, Linet MS, Kwon D, Simon SL: Occupational radiation doses to operators performing cardiac catheterization procedures. Health Phys 2008, 94:211–227. 15. Sauren LD, van Garsse L, van Ommen V, Kemerink GJ: Occupational radiation dose during transcatheter aortic valve implantation. Catheter Cardiovasc Interv 2011, 8:770–776. 16. Panuccio G, Greenberg RK, Wunderle K, Mastracci TM, Eagleton MG, Davros W: Comparison of indirect radiation dose estimates with directly measured radiation dose for patients and operators during complex endovascular procedures. J Vasc Surg 2011, 53:885–894. 17. Venneri L, Rossi F, Botto N, Andreassi MG, Salcone N, Emad A, Lazzeri M, Gori C, Vano E, Picano E: Cancer risk from professional exposure in staff working in cardiac catheterization laboratory: insights from the National Research Council's Biological Effects of Ionizing Radiation VII Report. Am Heart J 2009, 157:118–124. 18. Dragusin O, Weerasooriya R, Jaïs P, Hocini M, Ector J, Takahashi Y, Haïssaguerre M, Bosmans H, Heidbüchel H: Evaluation of a radiation protection cabin for invasive electrophysiological procedures. Eur Heart J 2007, 28:183–189. 19. Renaud L: A 5-y follow-up of the radiation exposure to in-room personnel during cardiac catheterization. Health Phys 1992, 62:10–15. 20. Vaño E, Gonzalez L, Fernandez JM, Alfonso F, Macaya C: Occupational radiation doses in interventional cardiology: a 15-year follow-up. Br J Radiol 2006, 79:383–388. 21. Vano E, Kleiman NJ, Duran A, Rehani MM, Echeverri D, Cabrera M: Radiation cataract risk in interventional cardiology personnel. Radiat Res 2010, 174:490–495. 22. Kim C, Vasaiwala S, Haque F, Pratap K, Vidovich MI: Radiation safety among cardiology fellows. Am J Cardiol 2010, 106:125–128. 23. Watson RM: Radiation exposure: clueless in the cath lab, or sayonara ALARA. Cathet Cardiovasc Diagn 1997, 42:126–127. 24. Correia MJ, Hellies A, Andreassi MG, Ghelarducci B, Picano E: Lack of radiological awareness among physicians working in a tertiary-care cardiological centre. Int J Cardiol 2005, 103:307–311. 25. Mancuso M, Pasquali E, Leonardi S, Tanori M, Rebessi S, Di Majo V, Pazzaglia S, Toni MP, Pimpinella M, Covelli V, Saran A: Oncogenic bystander radiation effects in Patched heterozygous mouse cerebellum. Proc Natl Acad Sci U S A 2008, 105:12445–12450. 26. Annual Report of the International Commission on Radiological Protection.; 1997. http://www.icrp.org. 27. Pflugbeil S, Pflugbeil C, Schitz-Fenerhake I: Risk estimates for meningiomas and other late effects after diagnostic X-ray exposure of the skull. Rad Prot Dosimetry 2011, 147:305–309.