X-Ray Personnel Security Screening Systems Update

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X-Ray Personnel Security Screening Systems Update

• Presented to TEPRSSC
• October 1, 2003
• Gaithersburg, MD

2
Background (1)

• Sep. 1998 TEPRSSC recommends a
• mandatory standard for backscatter systems.
• Apr. 1999 FDA proposes new consensus standard
  to ANSI/HPS N43.
• Apr. 2002 Radiation Safety for Personnel
  Screening Systems Using X Rays, becomes voluntary
  standard N43.17.
• June 2002 Transmission systems are discussed at
  TEPRSSC meeting need for mandatory standard was
  restated.

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Background (2)

• In 2002 TEPRSSC recommended a mandatory standard
  based on ANSI N43.17 performance requirements.
• TEPRSSC also recognized that, although present
  transmission systems do not meet these
  requirements, there may be a limited number of
  legitimate uses for these systems (e.g. in lieu
  of a using a medical x-ray unit for the detection
  of swallowed contraband).
• It was proposed that the mandatory standard allow
  for exceptions, providing for appropriate
  manufacturers instructions, to allow such
  limited uses.

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ANSI N43.17 Dose Limits

• 0.1?Sv (10 µrem) effective dose per scan
• 250 ?Sv (25 mrem) effective dose per year

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New Documents

• Health Physics Society Position Statement Use of
  ionizing radiation for security screening
  individuals.
• NCRP Presidential Report on Radiation Protection
  Advice Screening of Humans for Security Purposes
  Using Ionizing Radiation Scanning Systems.

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HPS Position Statement (1)

• The practice should be limited to those
  applications that result in an overall net
  benefit to society.
• When the practice is used to screen members of
  the general public, screening systems and their
  use should conform to the requirements of
  ANSI/HPS N43.17.
• Subjects should be informed of the radiation
  exposure.

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HPS Position Statement (2)

• Appropriate organizations should develop
  criteria for determining when the social benefits
  of public screening outweigh the risks associated
  with ionizing radiation exposure. The criteria
  should represent the consensus of professional,
  consumer-advocacy, labor, and business
  organizations academic institutions government
  agencies and the general public.

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NCRP SC 1-12

• FDA with co-sponsorship from the Transportation
  Security Administration (TSA) requested guidance
  from the National Council on Radiation Protection
  and Measurements (NCRP).
• NCRP Presidential Report format was chosen for
  speed (now being published as NCRP Commentary 16).

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FDAs Request to NCRP for Guidance (1)

• Risk assessment
• Appropriate use conditions
• Targeted and susceptible populations
• Dose limits
• Informed consent

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FDAs Request to NCRP for Guidance (2)

• Operator qualifications
• Benefit vs. risk (net benefit?)
• Record keeping
• General screening vs. follow-up evaluations

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NCRP Report SC 1-12Scope (1)

• Is compatible with present NCRP system of
  radiation protection.
• Includes brief review of known risks.
• Considers potentially screened populations and
  susceptible subgroups.
• Makes dose recommendations based on radiation
  safety and usefulness of images.

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NCRP Report SC 1-12Scope (2)

• Addresses
• Need for communication of radiation exposure and
  effects
• Operator training requirements
• Recordkeeping
• Testing of equipment

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NCRP Report SC 1-12Scope (3)

• Does not address
• Net benefit - justification for use is outside of
  the role of NCRP

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NCRP Report SC 1-12Bottom Line (1)

• Ionizing radiation dose from security screening
  must conform with NCRP-116 recommendation for
  frequent exposures for the general public
• 1 mSv/y (100 mrem/y) effective dose from all
  non-medical, man-made sources

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NCRP Report SC 1-12Bottom Line (2)

• The NCRP-116 administrative control of 0.25 mSv
  (25 mrem) annual effective dose to an individual
  from sources under one control (one venue) is a
  more practical alternative, albeit still
  potentially difficult to verify.
• The administrative control adequately protects
  all population groups.

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NCRP Report SC 1-12 Recommendations (1)

• Two Categories
• General-Use Systems
• Conform with ANSI N43.17 dose requirement of 0.1
  ?Sv/scan
• (10 ?rem/scan)
• Limited-Use Systems
• Between 0.1 and 10 ?Sv/scan
• (10 ?rem to 1 mrem/scan)

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NCRP Report SC 1-12 Recommendations (2)

• General-Use Systems
• May be used for screening general public.
• Limited-Use Systems
• Must be used with discretion (e.g. second tier
  screening).
• Should consider non-ionizing alternatives.
• Must limit usage so that any one individual not
  exceed 0.25 mSv in a year from one site.

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NCRP Report SC 1-12 Recommendations (3)

• Users of limited-use systems must assume
  responsibility of providing reasonable assurance
  that the annual administrative control is not
  exceeded.
• Written protocols
• Record keeping

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NCRP Report SC 1-12 Recommendations (4)

• Bystanders
• Should have the same level of protection as
  individuals screened
• (i.e. 0.25 mSv/y from one site).
• Operators
• The same level of protection is recommended.

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NCRP Report SC 1-12 Recommendations (5)

• Equipment testing
• Initially (after installation)
• After maintenance or repair
• Operator training
• See NCRP reports 127, 133, 134
• List of 25 topics to be covered
• Annual refresher training followed by testing

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NCRP Report SC 1-12 Recommendations (6)

• Information to individual scanned
• Risk, benefit, and comparative examples
• Should be provided in lay terms prior to
  screening
• Should be disseminated and readily available
• Informed consent
• Not necessary

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Recapitulation

• In 2002 TEPRSSC recommended a mandatory standard
  based on ANSI N43.17 performance requirements.
• TEPRSSC also recognized that, although present
  transmission systems do not meet these
  requirements, there may be a limited number of
  legitimate uses for these systems (e.g. in lieu
  of a using a medical x-ray unit for the detection
  of swallowed contraband).
• It was proposed that the mandatory standard allow
  for exceptions, providing for appropriate
  manufacturers instructions, to allow such
  limited uses.

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Conclusion

• In the past year two leading radiation protection
  institutions, HPS and NCRP, went on record on the
  issue of x-ray screening of people for security
  purposes. Their recommendations are in harmony
  with the 2002 TEPRSSC recommendations. FDA will
  take all these documents and the previous CRCPD
  resolution into consideration in drafting a
  mandatory standard.