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Health effects of security scanners for passenger screening (based on X-ray technology) (EU/EC, May 7 2012, edited)
[Source: European Union, full PDF document: (LINK). Abstract, edited.]
Scientific Committee on Emerging and Newly Identified Health Risks
SCENIHR
Health effects of security scanners for passenger screening (based on X-ray technology)
SCENIHR approved this opinion by written procedure on 26 April 2012
About the Scientific Committees
Three independent non-food Scientific Committees provide the Commission with the scientific advice it needs when preparing policy and proposals relating to consumer safety, public health and the environment. The Committees also draw the Commission's attention to the new or emerging problems which may pose an actual or potential threat.
They are: the Scientific Committee on Consumer Safety (SCCS), the Scientific Committee on Health and Environmental Risks (SCHER) and the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) and are made up of external experts.
In addition, the Commission relies upon the work of the European Food Safety Authority (EFSA), the European Medicines Agency (EMA), the European Centre for Disease prevention and Control (ECDC) and the European Chemicals Agency (ECHA).
SCENIHR
This Committee deals with questions related to emerging or newly identified health and environmental risks and on broad, complex or multidisciplinary issues requiring a comprehensive assessment of risks to consumer safety or public health and related issues not covered by other Community risk assessment bodies. Examples of potential areas of activity include potential risks associated with interaction of risk factors, synergic effects, cumulative effects, antimicrobial resistance, new technologies such as nanotechnologies, medical devices including those incorporating substances of animal and/or human origin, tissue engineering, blood products, fertility reduction, cancer of endocrine organs, physical hazards such as noise and electromagnetic fields (from mobile phones, transmitters and electronically controlled home environments), and methodologies for assessing new risks. It may also be invited to address risks related to public health determinants and non-transmissible diseases.
Scientific Committee members
Anssi Auvinen, James Bridges, Kenneth Dawson, Wim De Jong, Philippe Hartemann, Peter Hoet, Thomas Jung, Mats-OlofMattsson, HannuNorppa, Jean-Marie Pag?s, Ana Proykova, Eduardo Rodr?guez-Farr?, Klaus Schulze-Osthoff, Joachim Sch?z, Mogens Thomsen, Theo Vermeire
Contact:
European Commission, DG Health & Consumers, Directorate D: Health Systems and Products, Unit D3 - Risk Assessment, Office: B232 08/015 B-1049 Brussels - Sanco-SCENIHR-Secretariat@ec.europa.eu
? European Union, 2012
ISSN 1831-4783
doi:
The opinions of the Scientific Committees present the views of the independent scientists who are members of the committees. They do not necessarily reflect the views of the European Commission. The opinions are published by the European Commission in their original language only.
http://ec.europa.eu/health/scientific_committees/policy/index_en.htm
ACKNOWLEDGMENTS
The members of the Working Group are acknowledged for their valuable contribution to this opinion. They are:
SCENIHR members:
Prof. Anssi Auvinen (Chair and Rapporteur), University of Tampere and STUK ? Radiation and Nuclear Safety Authority, FI (this work was carried out during tenure as Senior Visiting Scientist at the International Agency for Research on Cancer, Lyon, FR)
Dr. Thomas Jung, Paul Scherrer Institute, CH
Prof. Ana Proykova, University of Sofia, BG
SCHER members:
Prof. Denis Bard, Ecole des Hautes Etudes en Sant? Publique, Rennes, FR
External experts:
Prof. Richard Paynter, Health Protection Agency, Chilton, UK
Dr. Geraldine O'Reilly, St James Hospital, Dublin, IRL
Prof. Christoph Hoeschen, Helmholtz Zentrum M?nchen, DE
Prof. Peter O'Neill, University of Oxford, UK
The additional contribution of the following experts is gratefully acknowledged:
Maria Zankl, Helmholtz Zentrum M?nchen, DE
All Declarations of Working Group members and supporting experts are available at the following webpage: http://ec.europa.eu/health/scientific_committees/emerging/members_wg/index_en.htm
ABSTRACT
Due to increased concern over terrorist attacks on aircraft, new technologies have been developed to improve the efficiency of security screening of passengers. Some of these technologies use ionising radiation (X-rays). As the hazards related to ionising radiation include the well-known carcinogenic risk, as well as other health effects, the SCENIHR was asked to assess the risks related to use of security scanners for passenger screening that use ionising radiation. The X-ray based security screening technology used in passenger screening relies on two techniques: backscatter or transmission. In the backscatter technique, radiation is reflected from the subject and detected to form an image of the body showing any concealed objects worn on the body. The transmission technique detects X-rays emitted by the equipment that pass through the body of the subject. Any concealed object provides an image by attenuating the radiation. While the backscatter technique can only reveal objects at the surface of the body, the transmission technique also shows objects within the body if their contrast differs sufficiently from the surrounding body fluids or tissue.
The effective dose, which takes into consideration the type of radiation and the sensitivity of the body parts exposed, is the best parameter to assess the health risk from ionising radiation. The effective doses per scanned passenger are in the μSv range for the transmission technique and less than 1 μSv for the backscatter technique. The organ doses have generally the same order of magnitude. For persons scanned three times every working day, security scanning would result in an incremental effective dose of approximately 300 μSv (0.3 mSv) per year for the backscatter technique and close to 3 mSv per year for the transmission technique (assuming doses of 0.4 and 4 μSv per scan, respectively). The latter would exceed the dose limit for the general public and hence would not comply with the current radiation protection standards for the very extreme of the most frequently screened and therefore highest exposed group. The former remains within the range characterised as negligible by the US National Council on Radiation Protection and Measurements (NCRP).
Short-term (deterministic) health effects due to tissue damage cannot result from the doses delivered by security scanners. The long-term effects of ionising radiation include an increased cancer risk, which is assumed to be directly proportional to the dose received, without a safe threshold. However, direct evidence of an increased cancer risk in humans is only available down to dose levels of 20-100 mSv.
For lower doses, the risk estimation rests on linear extrapolation, a reasonable approximation based on both empirical observations and mechanistic inference. Other health effects of ionising radiation, such as hereditary effects, increased risks of cardiovascular and cerebrovascular disease, as well as opacities of the lens of the eye, are not considered pertinent for this opinion as there is no convincing evidence of their occurrence at such low doses. The potential magnitude of cancer risk from doses received from security scanners cannot be estimated, but is likely to remain so low that it cannot be distinguished from the effects of other exposures including both ionising radiation from other sources (including natural) and background risk due to other factors.
While the expected health detriment will probably be very close to zero for any single scanned person, the assessment of acceptability of the introduction of the security scanners using X-rays for passenger screening should also take into account the possible effect at the population level. Due to the substantial uncertainty regarding the potential occurrence of any health effects, risks for special groups within the population could not be evaluated meaningfully, although a higher risk related to exposure in childhood was noted.
Keywords: X-ray security scanners, X-ray transmission, X-ray backscatter, health effects, passenger screening
Opinion to be cited as:
SCENIHR (Scientific Committee on Emerging and Newly Identified Health Risks), Health effects of security scanners for passenger screening (based on X-ray technology), 26 April 2012
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Scientific Committee on Emerging and Newly Identified Health Risks
SCENIHR
Health effects of security scanners for passenger screening (based on X-ray technology)
SCENIHR approved this opinion by written procedure on 26 April 2012
About the Scientific Committees
Three independent non-food Scientific Committees provide the Commission with the scientific advice it needs when preparing policy and proposals relating to consumer safety, public health and the environment. The Committees also draw the Commission's attention to the new or emerging problems which may pose an actual or potential threat.
They are: the Scientific Committee on Consumer Safety (SCCS), the Scientific Committee on Health and Environmental Risks (SCHER) and the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) and are made up of external experts.
In addition, the Commission relies upon the work of the European Food Safety Authority (EFSA), the European Medicines Agency (EMA), the European Centre for Disease prevention and Control (ECDC) and the European Chemicals Agency (ECHA).
SCENIHR
This Committee deals with questions related to emerging or newly identified health and environmental risks and on broad, complex or multidisciplinary issues requiring a comprehensive assessment of risks to consumer safety or public health and related issues not covered by other Community risk assessment bodies. Examples of potential areas of activity include potential risks associated with interaction of risk factors, synergic effects, cumulative effects, antimicrobial resistance, new technologies such as nanotechnologies, medical devices including those incorporating substances of animal and/or human origin, tissue engineering, blood products, fertility reduction, cancer of endocrine organs, physical hazards such as noise and electromagnetic fields (from mobile phones, transmitters and electronically controlled home environments), and methodologies for assessing new risks. It may also be invited to address risks related to public health determinants and non-transmissible diseases.
Scientific Committee members
Anssi Auvinen, James Bridges, Kenneth Dawson, Wim De Jong, Philippe Hartemann, Peter Hoet, Thomas Jung, Mats-OlofMattsson, HannuNorppa, Jean-Marie Pag?s, Ana Proykova, Eduardo Rodr?guez-Farr?, Klaus Schulze-Osthoff, Joachim Sch?z, Mogens Thomsen, Theo Vermeire
Contact:
European Commission, DG Health & Consumers, Directorate D: Health Systems and Products, Unit D3 - Risk Assessment, Office: B232 08/015 B-1049 Brussels - Sanco-SCENIHR-Secretariat@ec.europa.eu
? European Union, 2012
ISSN 1831-4783
doi:
The opinions of the Scientific Committees present the views of the independent scientists who are members of the committees. They do not necessarily reflect the views of the European Commission. The opinions are published by the European Commission in their original language only.
http://ec.europa.eu/health/scientific_committees/policy/index_en.htm
ACKNOWLEDGMENTS
The members of the Working Group are acknowledged for their valuable contribution to this opinion. They are:
SCENIHR members:
Prof. Anssi Auvinen (Chair and Rapporteur), University of Tampere and STUK ? Radiation and Nuclear Safety Authority, FI (this work was carried out during tenure as Senior Visiting Scientist at the International Agency for Research on Cancer, Lyon, FR)
Dr. Thomas Jung, Paul Scherrer Institute, CH
Prof. Ana Proykova, University of Sofia, BG
SCHER members:
Prof. Denis Bard, Ecole des Hautes Etudes en Sant? Publique, Rennes, FR
External experts:
Prof. Richard Paynter, Health Protection Agency, Chilton, UK
Dr. Geraldine O'Reilly, St James Hospital, Dublin, IRL
Prof. Christoph Hoeschen, Helmholtz Zentrum M?nchen, DE
Prof. Peter O'Neill, University of Oxford, UK
The additional contribution of the following experts is gratefully acknowledged:
Maria Zankl, Helmholtz Zentrum M?nchen, DE
All Declarations of Working Group members and supporting experts are available at the following webpage: http://ec.europa.eu/health/scientific_committees/emerging/members_wg/index_en.htm
ABSTRACT
Due to increased concern over terrorist attacks on aircraft, new technologies have been developed to improve the efficiency of security screening of passengers. Some of these technologies use ionising radiation (X-rays). As the hazards related to ionising radiation include the well-known carcinogenic risk, as well as other health effects, the SCENIHR was asked to assess the risks related to use of security scanners for passenger screening that use ionising radiation. The X-ray based security screening technology used in passenger screening relies on two techniques: backscatter or transmission. In the backscatter technique, radiation is reflected from the subject and detected to form an image of the body showing any concealed objects worn on the body. The transmission technique detects X-rays emitted by the equipment that pass through the body of the subject. Any concealed object provides an image by attenuating the radiation. While the backscatter technique can only reveal objects at the surface of the body, the transmission technique also shows objects within the body if their contrast differs sufficiently from the surrounding body fluids or tissue.
The effective dose, which takes into consideration the type of radiation and the sensitivity of the body parts exposed, is the best parameter to assess the health risk from ionising radiation. The effective doses per scanned passenger are in the μSv range for the transmission technique and less than 1 μSv for the backscatter technique. The organ doses have generally the same order of magnitude. For persons scanned three times every working day, security scanning would result in an incremental effective dose of approximately 300 μSv (0.3 mSv) per year for the backscatter technique and close to 3 mSv per year for the transmission technique (assuming doses of 0.4 and 4 μSv per scan, respectively). The latter would exceed the dose limit for the general public and hence would not comply with the current radiation protection standards for the very extreme of the most frequently screened and therefore highest exposed group. The former remains within the range characterised as negligible by the US National Council on Radiation Protection and Measurements (NCRP).
Short-term (deterministic) health effects due to tissue damage cannot result from the doses delivered by security scanners. The long-term effects of ionising radiation include an increased cancer risk, which is assumed to be directly proportional to the dose received, without a safe threshold. However, direct evidence of an increased cancer risk in humans is only available down to dose levels of 20-100 mSv.
For lower doses, the risk estimation rests on linear extrapolation, a reasonable approximation based on both empirical observations and mechanistic inference. Other health effects of ionising radiation, such as hereditary effects, increased risks of cardiovascular and cerebrovascular disease, as well as opacities of the lens of the eye, are not considered pertinent for this opinion as there is no convincing evidence of their occurrence at such low doses. The potential magnitude of cancer risk from doses received from security scanners cannot be estimated, but is likely to remain so low that it cannot be distinguished from the effects of other exposures including both ionising radiation from other sources (including natural) and background risk due to other factors.
While the expected health detriment will probably be very close to zero for any single scanned person, the assessment of acceptability of the introduction of the security scanners using X-rays for passenger screening should also take into account the possible effect at the population level. Due to the substantial uncertainty regarding the potential occurrence of any health effects, risks for special groups within the population could not be evaluated meaningfully, although a higher risk related to exposure in childhood was noted.
Keywords: X-ray security scanners, X-ray transmission, X-ray backscatter, health effects, passenger screening
Opinion to be cited as:
SCENIHR (Scientific Committee on Emerging and Newly Identified Health Risks), Health effects of security scanners for passenger screening (based on X-ray technology), 26 April 2012
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