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).
What You Need to Know? 👇
What is the purpose of 21 CFR 1020.31(g)(1) regarding X-ray field size adjustment?
This regulation requires manufacturers to provide automatic adjustment of X-ray field size to match the selected spot-film size, except when the X-ray field is smaller than the selected film portion, to minimize unnecessary patient radiation exposure.
When can fluoroscopic systems maintain a smaller X-ray field size than the selected spot-film format?
Systems must allow fluoroscopists to maintain smaller X-ray field sizes when taking spot films if the field is already smaller than the selected format, preventing automatic enlargement that would increase patient radiation exposure unnecessarily.
What design options comply with FDA requirements for X-ray field size flexibility?
Acceptable designs include manual adjustment controls, activation switches for full format exposure, or dual-mode systems allowing fluoroscopists to choose between automatic sizing and manual control while meeting applicable PBL requirements.
How does this guidance impact patient safety in fluoroscopic procedures?
The guidance prioritizes patient safety by preventing automatic field enlargement that would expose patients to unnecessary radiation when fluoroscopists intentionally use smaller field sizes for diagnostic purposes during spot-film procedures.
What are the compliance requirements for X-ray systems using the same tube for multiple procedures?
Systems using the same X-ray tube for spot-film and other radiographic procedures must meet PBL requirements (21 CFR 1020.31(e)) in automatic mode and spot-film device requirements (21 CFR 1020.31(g)) in manual mode.
When was this FDA guidance on X-ray field size adjustment issued and what is its current status?
This guidance was issued in October 1980 as a final policy document to clarify manufacturer requirements under the Diagnostic X-Ray Standard, specifically addressing field limitation and alignment for spot-film devices.
What You Need to Do 👇
Recommended Actions
- Review current system design to ensure compliance with field size adjustment requirements
- Implement one of the three acceptable design options for field size control
- For dual-purpose X-ray tubes, ensure compliance with both PBL and spot-film device requirements
- Verify that system design prioritizes minimizing patient radiation exposure
- Document system controls and operational modes in technical documentation
- Ensure user interface clearly indicates current operational mode and control options
- 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
- Acceptable system designs must include one of the following:
- Manual adjustment to selected spot film size
- Switch/button activation required for each spot-film exposure
- Dual-mode operation with user-selectable automatic or manual adjustment
Relevant Guidances 🔗
- Radiation Safety Requirements for Diagnostic X-Ray Systems and Components
- Radiation Control Requirements and Interpretations for Diagnostic X-ray Equipment
- X-Ray Equipment Performance Standards and Radiation Safety Requirements
- Harmonization of Performance Standards for Diagnostic X-Ray Imaging Systems and Components with IEC Standards
Related references and norms 📂
- 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 ID: d5dc2c1b008d4922d8053416eea18d54