Governance

The purpose of this joint statement by the American Association of Physicists in Medicine (AAPM), the Conference of Radiation Control Program Directors (CRCPD), and Medical Imaging Technology Alliance (MITA) is to clarify the implications of the recent FDA guidance that, under certain circumstances, permits manufacturers of medical x-ray imaging equipment to conform to relevant International Electrotechnical Commission (IEC) standards in lieu of certain FDA performance standards for clinical medical physicists, regulatory and accrediting bodies, and clinical users.  AAPM and CRCPD meet regularly with FDA and the latter has given numerous presentations on the planned guidance since 2016. AAPM and CRCPD have provided feedback on FDA and industry’s approach to meeting the needs of all relevant participants.

FDA regulates medical x-ray imaging devices as both medical devices and electronic products. Electronic products are regulated by FDA through its Electronic Product Radiation Control (EPRC) regulations. The EPRC regulations are aimed at protecting the public from hazardous and unnecessary exposure to radiation from electronic products. A guidance document published by FDA in 2019, entitled “Medical X‐Ray Imaging Devices Conformance with IEC Standards”, permits manufacturers of medical x-ray imaging equipment to conform to relevant IEC Standards in lieu of certain EPRC regulations. ¹ This flexibility is widely supported by device manufacturers, and recognized by medical physicists and regulators to have benefits because the IEC Standards are developed by an international consensus process and are updated regularly. The relevant IEC Standards provide, at a minimum, the same level of protection of the public health and safety from electronic radiation as certain EPRC performance Standards and reporting requirements. This guidance document has no effect on the medical device regulations.

FDA regulations require manufacturers to supply adequate instructions for assembly, installation, adjustment, and testing (AIAT) to assemblers and, upon request, to anyone else (21 CFR 1020.30(g)). The guidance document recommends that a manufacturer who chooses to declare conformity to IEC Standards in lieu of certain EPRC regulations comply with FDA requirement by supplying AIAT instructions that include a Radiation Safety Specification and Testing Comparison Document. This document, at minimum, should include inter alia: radiation safety specifications that apply to the device, where those specifications would not otherwise meet the comparable EPRC performance Standards; IEC document number, version, and specific clause(s) under which each such specification is found; EPRC performance Standard requirement being replaced by the IEC Standard; and the test method and acceptance criterion. The intent is to format the AIAT documentation so that all radiation safety specifications and necessary test methods are available in a format that is practical for all and that does not require access to the relevant IEC Standards.

Industry, through MITA, supports this Radiation Safety Specification and Testing Comparison Document as a reasonable least-burdensome approach to communicate IEC specifications and test methods that are different from 21 CFR requirements.  This allows medical physicists and state inspectors to understand the requirements and update their testing procedures accordingly. Through the process of creating and vetting modality-specific tables, MITA confirms referenced IEC Standards contain similar and, in many cases, more prescriptive descriptions of specifications/tests than current 21 CFR Standards. MITA also commits to making these documents publicly available via a central Web-based “landing page,” hosted by MITA, which directs users to the dedicated manufacturer’s site  providing the information. The manufacturers retain autonomy on how the information is provided. Web links to table templates are available for download.^2,3

Manufacturers that choose to conform to IEC Standards must provide to FDA a declaration of conformity. IEC Standards typically include specific requirements and tests that permit a determination of whether those requirements have been met. Some of these tests are intended to be performed by the manufacturer or a test house, but not normally on installed equipment at a user facility. Some are intended to be performed by the installer at the user facility after the equipment is installed and before clinical use. Some are also intended to provide guidance for the user facility during acceptance and constancy testing and can be used by regulatory authorities who perform equipment testing.

In this statement, we clarify that the requirements of FDA EPRC regulations and the IEC Standards apply to x-ray equipment manufacturers, and not to clinical end users or others  for whom they are only a source of information. IEC acceptance and constancy test Standards are intended to guide manufacturers by setting a minimum baseline for what those tests should be and by providing consensus methodology on how the tests should be done. This then guides the manufacturer on what information to provide. Any regulatory requirements from state or local government are either in addition to, or supersede, the manufacturer’s recommendations. Individuals who perform acceptance and constancy tests must do so based on the requirements of state and local regulatory agencies and accreditation bodies such as ACR and The Joint Commission, taking into account the recommendations of equipment manufacturers and their own knowledge and experience.

References

1. Medical X-Ray Imaging Devices Conformance with IEC Standards. S. Food & Drug Administration. May 2019.  https://www.fda.gov/regulatory-information/search-fda-guidance-documents/medical-x-ray-imaging-devices-conformance-iec-standards
2. Radiation Safety Specification and Testing Comparison Document for Medical X-Ray Imaging Devices: General Radiography and Fluoroscopy, and Interventional Fluoroscopy. NEMA/MITA RSSTCD 1-2019. https://www.nema.org/Standards/view/Radiation-Safety-Specification-and-Testing-Comparison-Document-for-Medical-X-Ray-Imaging-Devices-General-Radiography-and-Fl
3. 21 CFR Subchapter J to IEC Comparison Table for Medical X-Ray Imaging Devices Mammography. NEMA/MITA RSSTCD 2-2020. https://www.nema.org/standards/view/21-cfr-subchapter-j-to-iec-comparison-table-for-medical-x-ray-imaging-devices-mammography

List of Members:

• Lifeng Yu, Co-Chair
• Kevin Wunderle, Co-Chair
• Bette Blankenship, committee member
• Renee Dickson Butler, committee member
• William DeForest, committee member
• Allen Goode, committee member
• Katie Hulme, committee member
• Amirh Johnson, committee member
• Steve Mann, committee member
• Donald Miller (FDA), committee member
• Beth Schueler, committee member
• Marlene Skopec, committee member
• Adam Springer, committee member
• Mark Supanich, committee member
• Dustin Gress (ACR), committee member
• Andrea Browne (Joint Commission), committee member
• Kirsten Boedeker (MITA), committee member
• Andrew Kuhls-Gilcrist (MITA), committee member
• Jennifer Elee, (CRCPD), committee consultant (non-AAPM member)
• Mary Ann Spohrer, (CRCPD), committee consultant (non-AAPM member)
• John Winston, (CRCPD), committee consultant (non-AAPM member)