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X-ray Field Size Control Requirements for Fluoroscopic and Spot-Film Systems

This guidance clarifies requirements for automatic adjustment of X-ray field size in fluoroscopic/spot-film systems, specifically addressing situations where the X-ray field size is smaller than the selected spot-film size, as per 21 CFR 1020.31(g)(1).

  1. Review current system design to ensure compliance with field size adjustment requirements
  2. Implement one of the three acceptable design options for field size control
  3. For dual-purpose X-ray tubes, ensure compliance with both PBL and spot-film device requirements
  4. Verify that system design prioritizes minimizing patient radiation exposure
  5. Document system controls and operational modes in technical documentation
  6. Ensure user interface clearly indicates current operational mode and control options
  7. Validate that fluoroscopist maintains control over field size selection at all times

Key Considerations

Human Factors

  • System must allow fluoroscopist to maintain control over X-ray field size
  • Manual controls or mode selection must be easily accessible to the operator

Safety

  • System must prevent automatic enlargement of X-ray field size when current field is smaller than selected spot-film size
  • Design must minimize unnecessary radiation exposure to patients
  • For systems using same X-ray tube for spot film and other radiographic procedures, PBL requirements must be met

Other considerations

  • 21 CFR 1020.31: Performance standards for radiographic equipment

Original guidance

  • X-ray Field Size Control Requirements for Fluoroscopic and Spot-Film Systems
  • HTML
  • Issue date: 1980-09-30
  • Last changed date: 2018-12-01
  • Status: FINAL
  • Official FDA topics: Medical Devices, Radiation-Emitting Products, Radiology, Investigation & Enforcement
  • ReguVirta summary file ID: d5dc2c1b008d4922d8053416eea18d54
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