Solid State X-ray Imaging Devices for Medical Diagnostic Use
This guidance applies to Solid State X-ray Imagers (SSXI) that convert x-ray patterns into electrical signals for medical diagnosis. It covers devices intended to replace conventional x-ray film/screen systems and image intensifier-based fluoroscopic systems, excluding devices for mammography.
What You Need to Know? 👇
What are the main types of solid state X-ray imaging devices covered by FDA guidance?
The guidance covers four main types: scintillator-photodetector devices, direct conversion devices, optically coupled CCD systems, and photostimulable phosphor devices. Each uses different mechanisms to convert X-ray photons into electrical signals for medical imaging.
What regulatory requirements must solid state X-ray imagers meet before marketing?
Devices must comply with the Radiation Control for Health and Safety Act (RCHSA) and Medical Device Amendments (MDA). They need 510(k) clearance demonstrating substantial equivalence to predicate devices and must meet applicable performance standards under 21CFR1020.30-32.
When is clinical data required for 510(k) submissions of solid state X-ray devices?
Clinical data may not be necessary for modifications like dimensional changes, pixel size/resolution changes, or wireless functionality additions. However, clinical studies or qualified expert evaluations are required when nonclinical data alone cannot demonstrate substantial equivalence.
What is Detective Quantum Efficiency (DQE) and why is it important for these devices?
DQE measures how efficiently a detector converts X-ray photons into useful image information while minimizing noise. It’s crucial for demonstrating that solid state devices operate in quantum-limited mode, meaning device noise doesn’t exceed X-ray quantum noise.
What quality assurance program elements must be included in 510(k) submissions?
Submissions must describe parameter monitoring procedures, quality criteria/acceptance limits, manufacturer record-keeping requirements, and QA training materials. This ensures continued proper functioning of the device, control hardware, software, and power supplies throughout its lifecycle.
How many clinical images are needed for qualified expert evaluation in 510(k) submissions?
For general radiographic indications, FDA recommends evaluating clinical images covering key anatomical regions including chest (PA/lateral), pelvis, abdomen, spine views, shoulder, and extremities. A full 30-image set may not be necessary if images sufficiently demonstrate system capability.
What You Need to Do 👇
Recommended Actions
- Determine if clinical testing is needed based on device modifications
- Prepare comprehensive non-clinical testing documentation including:
- Physical and operational characteristics
- Performance measurements (DQE, MTF, etc.)
- Test results with sample images
- Develop complete labeling package including:
- Indications for use
- User manuals and instructions
- Training materials
- Performance documentation
- Establish Quality Assurance Program with:
- Monitoring procedures
- Acceptance criteria
- Record keeping system
- Training materials
- Ensure compliance with radiation safety standards
- Consider pre-submission consultation with FDA for feedback on testing requirements
- Prepare 510(k) submission incorporating all required elements from guidance
Key Considerations
Clinical testing
- Concurrence study with 30+ clinical image pairs showing equivalent diagnostic capability to predicate device
- Qualified expert evaluation of representative clinical images for intended anatomical regions
- Clinical images must be accompanied by acquisition parameters and dose information
- Clinical testing may not be needed for certain modifications (dimension changes, pixel size changes, wireless functionality changes)
Non-clinical testing
- Physical characteristics (dimensions, sensor elements, structure, interconnections)
- Operational functions (exposure methods, x-ray absorption, energy conversion, readout mechanisms)
- Functional characteristics (DQE, MTF, dynamic range, lag effects, defect handling)
- Exposure characteristics (dose requirements, stability, uniformity, frame rates)
- Test results with sample images and measurements
Labelling
- Indications for use
- Promotional materials
- Instructions for installation, checkout and use
- Training materials
- Documentation of imaging performance characteristics
Safety
- Ready signal indication for x-ray input acceptance
- Compliance with radiation safety standards
- Safety features documentation
Other considerations
- Quality Assurance Program requirements
- Parameter monitoring procedures
- Quality criteria and acceptance limits
- Manufacturer records maintenance
- QA training materials
Relevant Guidances 🔗
- Technical Performance Assessment and Premarket Requirements for Digital Diagnostic Radiology Display Devices
- Harmonization of Performance Standards for Diagnostic X-Ray Imaging Systems and Components with IEC Standards
- Performance Standard Requirements for Fluoroscopic X-Ray Systems: Timing, Safety Features and Display Requirements
- Pediatric X-Ray Imaging Device Premarket Submissions: Design, Testing, and Labeling Considerations
Related references and norms 📂
- 21 CFR 1020.30: Diagnostic x-ray systems and their major components
- 21 CFR 1020.31: Radiographic equipment
- 21 CFR 1020.32: Fluoroscopic equipment
- 21 CFR Parts 50 and 56: Protection of Human Subjects and Institutional Review Boards