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					    Update on Proposed Amendments
     to the Performance Standard for
         Diagnostic X-ray Systems
             (21 CFR 1020.30 - .33)
    (The Fluoroscopic System Amendments)
                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
1                 301-443-3314 ext. 132
                         Outline
     Background on amendment development.

     Status of comments.

     Estimated schedule for completion.

     Future role of international standards?

     Advice or comment from the committee
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                    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

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        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
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      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
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      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
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      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


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    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



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           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

9
             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)
10
     Reference location for system with
                 isocenter
                                       Dose rate or
                             Monitor
                                       cumulative
                                       dose
                        Shield         at reference
                                       point

             15 cm
                        Shield




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     Proposed display of dose information


                   mGy/min                 mGy/min
            8.3    mGy              66.8   mGy




      During irradiation     Following irradiation
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      Air kerma rate         Cumulative air kerma
     Alternative display of dose information


                4.8     mGy/min   Display of air kerma
       Air kerma rate             rate during
                                  irradiation.
             127.5      mGy
                                  Continuous display
      Cumulative air              of cumulative air
      kerma                       kerma.



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        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?



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               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)
15
      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
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     Skin dose “mapping” system




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      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
18
Electronic “cropping” of digital images

                              Area of image
                              receptor

                            X-ray field
                            area


                            Area of stored
                            image

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Electronic “cropping” of digital images

                         X-ray field



                   Stored and displayed image




20
“Cropping” of poorly collimated image

                            Area of image
                            receptor


                             X-ray field


                           Area of stored
                           image

21
“Cropping” of poorly collimated image


                             X-ray field border



                  Stored and displayed image




22
                   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?

23
        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
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           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.

25
        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
26
          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?

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      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?
28
     Comments & Questions




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posted:8/26/2011
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