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Enforcement Policy for Positive-Beam Limitation Requirements in Diagnostic X-Ray Systems

This guidance outlines the enforcement policy for Positive-Beam Limitation (PBL) requirements in diagnostic X-ray systems following the May 3, 1993 amendment to the Performance Standard. The amendment allows assemblers to install manual beam-limiting devices (BLD) in stationary, general-purpose radiographic x-ray (GP) systems, eliminating the mandatory PBL requirement while maintaining PBL requirements for systems equipped with it.

  1. Update testing procedures based on system configuration (with/without table, PBL/manual BLD)
  2. Document any user modifications to PBL systems
  3. Implement proper testing methods for maximum EER measurements with large field image intensifiers
  4. Consider field coverage limitations when testing systems with small target angle X-ray tubes
  5. Maintain records of installation dates and system modifications
  6. Ensure compliance with applicable Performance Standard requirements for systems equipped with PBL
  7. Train testing personnel on the updated requirements and procedures

Key Considerations

Non-clinical testing

  • Routine testing of GP systems with x-ray table should continue using Abovetable X-Ray Source Radiographic Systems (AR) test procedure
  • For GP systems without table and equipped with manual BLD, use Vertical Cassette Radiographic Systems (VC) test procedure
  • For GP systems without table but equipped with PBL, use Chiropractic Supplement to the AR procedure (ARB)
  • Verify PBL mode functionality at installation and during testing

Safety

  • PBL systems must prevent exposure until proper collimation is achieved
  • PBL must operate correctly at designated source-image receptor distances (SID)
  • Users can modify systems under 21 CFR 1020.30(q)(2) if modifications don’t result in non-compliance

Other considerations

  • 21 CFR 1020.31(g): Performance Standard for Diagnostic X-Ray Systems and Their Major Components
  • 21 CFR 1020.30(q)(2): Modifications by system owners

Original guidance

  • Enforcement Policy for Positive-Beam Limitation Requirements in Diagnostic X-Ray Systems
  • HTML / PDF
  • Issue date: 1993-10-13
  • Last changed date: 2020-03-17
  • Status: FINAL
  • Official FDA topics: Medical Devices, Radiation-Emitting Products, Postmarket, Investigation & Enforcement
  • ReguVirta summary file ID: 13de13b96f0d69900fe33542aa95c115
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