1. 1 Thomas B. Shope 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)

2. 2 Outline wBackground on amendment development. wStatus of comments. wEstimated schedule for completion. wFuture role of international standards? wAdvice or comment from the committee

3. 3 Background wCommunity 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 wDevelopment of IEC Standard 60601-2-43: Particular requirements for the safety of X-ray equipment for interventional procedures wConcerns over radiation injuries from fluoroscopy

4. 4 FDA’s Actions Regarding Fluoroscopic X-ray Systems w1993 - Proposed rule regarding limit on maximum exposure rate during high-level control mode w1995 - Final rule effective, other amendments needed w1997 - ANPR for additional amendments published wDiscussion of concepts for amendments and proposed rule with TEPRSSC at 1997 and 1998 meetings w“Year 2000 Problem” diverts resources/delays progress

5. 5 FDA’s Actions Regarding Fluoroscopic X-ray Systems wDecember 2002 - Proposed rule published following development of impact analysis, estimates of costs and benefits wComment period ended April 10, 2003 wFDA consideration of comments wPreparation of Final Rule

6. 6 Comments on proposed rule wComments 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 wComments, in general, were in favor of amendments

7. 7 Comments on proposed rule wSome objections to specific proposals or details wChanges 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 wSeveral comments urged “harmoniztion” with IEC standards for x-ray equipment

8. 8 Examples of specific comments wModify definitions wDesire 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

9. 9 Comments on Definitions wAttenuation block - size, thickness wMode of operation - single control in IEC standard wC-arm fluoroscope wExposure - definition of second meaning (loading) wIsocenter wSolid state x-ray imaging device wVisible area wOthers

10. 10 Critiques of proposed requirements wManufacturer description of intended uses for specific modes of operation in user information wManner and accuracy of dose display data wUltimate responsibility for modifications initiated by user/owner wAudible signal during fluoroscopy - conflict with current IEC standard 60601-2-7 for generators wApplication of dose display and last image hold to mini C-arm systems (SID < 45 cm)

11. 11 Reference location for system with isocenter Shield Monitor 15 cm Dose rate or cumulative dose at reference point

12. 12 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

13. 13 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

14. 14 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?

15. 15 Critiques of proposed requirements wManufacturer description of intended uses for specific modes of operation in user information wManner and accuracy of dose display data wUltimate responsibility for modifications initiated by user/owner wAudible signal during fluoroscopy - conflict with current IEC standard 60601-2-7 for generators wApplication of dose display and last image hold to mini C-arm systems (SID < 45 cm)

16. 16 Additional changes not in NPR wRequire info and tools for troubleshooting, repair, service, and testing wSpecification of voltage (kVp) waveform wUse specific IEC requirements - dose info, test procedures, primary protective barrier wDisplay peak skin dose and “skin dose map” wDisplay of collimation without irradiation wIndication of x-ray beam-on and “live image” wPost-exposure “image cropping” of digital images

17. 17 Skin dose “mapping” system

18. 18 Additional changes not in NPR wRequire info and tools for troubleshooting, repair, service, and testing wSpecification of voltage (kVp) waveform wUse specific IEC requirements - dose info, test procedures, primary protective barrier wDisplay peak skin dose and “skin dose map” wDisplay of collimation without irradiation wIndication of x-ray beam-on and “live image” wPost-exposure “image cropping” of digital images

19. 19 Electronic “cropping” of digital images Area of image receptor X-ray field area Area of stored image

20. 20 Electronic “cropping” of digital images Stored and displayed image X-ray field

21. 21 “Cropping” of poorly collimated image Area of image receptor X-ray field Area of stored image

22. 22 X-ray field border Stored and displayed image “Cropping” of poorly collimated image

23. 23 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?

24. 24 Errors and omissions noted wDiscussion of “unique” modes of operation and dose information for them wOmission of effective date for 1020.32(m)(2) and clarification of requirement to indicate filtration used wAttenuation of material between patient and image receptor wTolerance on dose display data - 1020.30(h)(6)(i) wTypo in proposed 1020.32(k)(5)(ii) describing the alternate location of the reference point

25. 25 Schedule for completion wFinalize decisions regarding regulatory wording wDraft Federal Register notice for final rule that responds to comments wCDRH, FDA, HHS and OMB review of FR notice wAnticipate completion by end of calendar 2003, rule would be effective in late 2004 or early 2005.

26. 26 Future role of international (IEC) standards? wRelationship 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

27. 27 Future role of international (IEC) standards? wCould 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?

28. 28 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?

29. 29 Comments & Questions