# Presentation: 802645

## Update on Proposed Amendments

- Office of Science and Technology
- Center for Devices and Radiological Health
- U.S. Food and Drug Administration
- Rockville, Maryland
- tbs@cdrh.fda.gov
- 301-443-3314  ext. 132

**Update on Proposed Amendments**
**to the Performance Standard for Diagnostic X-ray Systems**
**(21 CFR 1020.30 - .33)**
**(The Fluoroscopic System Amendments)**

## Outline

- Background on amendment development.
- Status of comments.
- Estimated schedule for completion.
- Future role of international standards?
- Advice or comment from the committee

## Background

**Community recognized need for amendments to address changes in technology in early 1990s**
**Increased radiation output capability and new imaging modes**
**Digital subtraction angiography, lithotripsy systems**
**1992 ACR/FDA Workshop on Fluoroscopy**
**Consensus on need for display of patient dose info**
**Development of IEC Standard 60601-2-43: Particular requirements for the safety of X-ray equipment  for interventional procedures**
**Concerns over radiation injuries from fluoroscopy**

## FDA’s Actions Regarding Fluoroscopic  X-ray Systems

- 1993 - Proposed rule regarding limit on maximum exposure rate during high-level control mode
- 1995 - Final rule effective, other amendments needed
- 1997 - ANPR for additional amendments published
- Discussion of concepts for amendments and proposed rule with TEPRSSC at 1997 and 1998 meetings
- “Year 2000 Problem” diverts resources/delays progress

## FDA’s Actions Regarding Fluoroscopic  X-ray Systems

- December 2002 - Proposed rule published following development of impact analysis, estimates of costs and benefits
- Comment period ended April 10, 2003
- FDA consideration of comments
- Preparation of Final Rule

## Comments on proposed rule

- Comments from 12 individuals or organizations
- Two state agencies
- Three professional associations
- One industry association
- Two x-ray equipment manufacturers
- Four individuals, including one medical physicist and one radiation effects researcher
- Comments, in general, were in favor of amendments

## Comments on proposed rule

- Some objections to specific proposals or details
- Changes suggested to the standard that were not part of FDA’s proposal - Such changes would generally require an additional proposal for comment
- Definitions, clarifications, significant changes
- Several comments urged “harmoniztion” with IEC standards for x-ray equipment

## Examples of specific comments

- Modify definitions
- Desire to consult/confer with FDA on development of additional requirements
- Dose limits for input to the image receptor
- Imaging performance
- Characterization and requirements for solid state x-ray imaging devices

## Comments on Definitions

- Attenuation block - size, thickness
- Mode of operation - single control in IEC standard
- C-arm fluoroscope
- Exposure - definition of second meaning (loading)
- Isocenter
- Solid state x-ray imaging device
- Visible area
- Others

## Critiques of proposed requirements

- Manufacturer description of intended uses for specific modes of operation in user information
- Manner and accuracy of dose display data
- Ultimate responsibility for modifications initiated by user/owner
- Audible signal during fluoroscopy - conflict with current IEC standard 60601-2-7 for generators
- Application of dose display and last image hold to mini C-arm systems (SID < 45 cm)

## Reference location for system with isocenter

- Shield

- Shield

- Monitor

- 15 cm

- Dose rate or
- cumulative dose
- at reference point

## Proposed display of dose information

**8.3**

**mGy/min**
**mGy**

- During irradiation
- Air kerma rate

**mGy/min**
**mGy**

**66.8**

- Following irradiation
- Cumulative air kerma

**Proposed display of dose information**

## Alternative display of dose information

**mGy/min**

**mGy**

**Air kerma rate**

**Cumulative air kerma**

**Display of air kerma rate during irradiation.  **
**Continuous display of cumulative air kerma.**

**Alternative display of dose information**

**4.8**

**127.5**

## Accuracy of dose display?

- Proposed accuracy of display of  25%
- IEC Standard 60601-2-43 requires  50%
- Is an accuracy of better than  50% necessary?

## Critiques of proposed requirements

- Manufacturer description of intended uses for specific modes of operation in user information
- Manner and accuracy of dose display data
- Ultimate responsibility for modifications initiated by user/owner
- Audible signal during fluoroscopy - conflict with current IEC standard 60601-2-7 for generators
- Application of dose display and last image hold to mini C-arm systems (SID < 45 cm)

## Additional changes not in NPR

- Require info and tools for troubleshooting, repair, service, and testing
- Specification of voltage (kVp) waveform
- Use specific IEC requirements - dose info, test procedures, primary protective barrier
- Display peak skin dose and “skin dose map”
- Display of collimation without irradiation
- Indication of x-ray beam-on and “live image”
- Post-exposure “image cropping” of digital images

## Skin dose “mapping” system

## Additional changes not in NPR

- Require info and tools for troubleshooting, repair, service, and testing
- Specification of voltage (kVp) waveform
- Use specific IEC requirements - dose info, test procedures, primary protective barrier
- Display peak skin dose and “skin dose map”
- Display of collimation without irradiation
- Indication of x-ray beam-on and “live image”
- Post-exposure “image cropping” of digital images

## Electronic “cropping” of digital images

- Area of image
- receptor

- X-ray field area

- Area of stored image

## Electronic “cropping” of digital images

- Stored and displayed image

- X-ray field

## “Cropping” of poorly collimated image

- Area of image
- receptor

- X-ray field

- Area of stored image

## “Cropping” of poorly collimated image

- X-ray field border

- Stored and displayed image

- “Cropping” of poorly collimated image

## Question?

- Are requirements about “electronic
- cropping” of digital images needed in
- performance standards for digital
- diagnostic x-ray systems?
- Initial display versus storage of images?

## Errors and omissions noted 

- Discussion of “unique” modes of operation and dose information for them
- Omission of effective date for 1020.32(m)(2) and clarification of requirement to indicate filtration used
- Attenuation of material between patient and image receptor
- Tolerance on dose display data - 1020.30(h)(6)(i)
- Typo in proposed 1020.32(k)(5)(ii) describing the alternate location of the reference point

## Schedule for completion

- Finalize decisions regarding regulatory wording
- Draft Federal Register notice for final rule that responds to comments
- CDRH, FDA, HHS and OMB review of FR notice
- Anticipate completion by end of calendar 2003, rule would be effective in late 2004 or early 2005.

## Future role of international (IEC) standards?

- Relationship between U.S. and IEC standards needs attention in global economy?
- No IEC standards when U.S. std. Developed
- Process for developing IEC standards different from the regulatory process
- Consensus of national committees
- Maintenance teams - structure being revised
- Are IEC standards “enforced” on manufacturers?
- FDA standards address only radiation safety performance

## Future role of international (IEC) standards?

- Could IEC standards be used in place of U.S. standards (for medical x-ray, for other electronic products)?
- How could they be enforced?
- Impact on State radiation control programs?
- Impact on Federal preemption?
- Could medical device authorities be used to assure compliance with “voluntary” IEC stds?

## Future role of international (IEC) standards?

- Could IEC standards be used without legislative changes?
- Would public health be protected if reliance placed on IEC standards?
- Could FDA or U.S. national committee play effective role in maintenance of IEC standards?
- Do current problems with Dx x-ray systems warrant continued mandatory standard?
- Would greater public health impact be obtained through other FDA activities?

## Comments & Questions