The Technical Electronic Product Radiation Safety Standards Advisory Committee met on June 21 & 22, 2000 in Rockville, MD. The following is a summary of the Committee’s considerations:
Dr. Elizabeth Jacobson, Deputy Director for Science, Center for Devices and Radiological Health, gave the committee an update on three issues which had been discussed at past meetings. The first was the proposed amendments to the federal performance standard for fluoroscopy x-ray devices (21 CFR, Part 1020). A major reason for proposing changes is the increased use of interventional radiology procedures, which can cause radiation burns to patients. The FDA feels that some relatively low cost equipment modifications can provide greater awareness of patient exposures. A draft Federal Register notice is now under internal FDA review.
The second issue discussed by Dr Jacobson was anti-theft electronic article surveillance systems. Last year it was suggested that manufacturers of medical devices and anti-theft systems cooperate in exploring possible instances of electronic interference with the functioning of implanted medical devices. Since that time there has been a Health Industry Manufacturers Association (HIMA) meeting on system labeling and a working group on pacemakers has been established. Information has been issued to clinicians, manufacturers, and retailers with advice about additional signs warning consumers not to linger or lean on the anti-theft machines. Further testing of implantable devices and their susceptibility to interference are expected, although current findings indicate a very low likelihood of interaction.
The third issue that Dr. Jacobson briefed the committee on was the significant progress made on wireless telemetry systems. There had been concerns about interference from hospital users of these systems which monitor patient vital signs. A cooperative effort between the American Hospital Association, Federal Communications Commission (FCC), and FDA resulted in a hospital alert on the problem and FCC coordination with TV broadcasters. It also resulted in a proposal for a new protected band for wireless medical telemetry; the FCC has proposed designating a saved space on the spectrum for medical users. A guidance document is being developed for industry, and a public health advisory has been issued. The FDA strongly supports the proposal to reserve space for wireless medical telemetry.
Following Dr Jacobson’s summary presentations, Mr. Jerry Dennis of the FDA discussed proposed amendments to the CDRH laser standard (21 CFR, Part1040). FDA is attempting to harmonize with standards currently being developed by the International Electrotechnical Commission (IEC). Mr. Dennis also summarized the status of the IEC amendments, noting that if approved, the amended IEC standard will be published in October 2000.
Dr. W. Howard Cyr next updated the committee on amendments to the Sunlamp Products Performance Standard. He stated that CDRH had published an advance notice of proposed rule making (ANPRM) on sunlamps in February 1999 and described the response to the ANPRM. Dr. Cyr stated that the FDA is not planning on banning sunlamps because the dangers of sunlamp use are fairly well understood by the public, and the science limited, i.e. the risk factors for melanoma and any association with sunlamp use are not well established. The agency plans to proceed to develop amendments pertaining to warning labels and maintenance requirements, and will consider making recommended exposure schedules a part of the standard. The FDA will seek the participation of both the sunlamp manufacturers and salon operators throughout the process of rulemaking.
Mr. Frank Cerra of the FDA reported that ANSI is developing a voluntary standard on radiation safety for ionizing radiation security systems. The scope of the effort is to include people scanners, but exclude such devices as scanners of large cargo vehicles such as trains and trucks. Mr Cerra discussed the ANSI standards development group, which is addressing issues such as the radiation dose people and operators may receive, how to measure these low levels of radiation, the need for proper operator training, and appropriate warning signs and labels. The goal is to produce a final draft by the end of 2000, and publication of a standard in 2002.
Dr. Robert Gagne gave the committee an update on computed tomography fluoroscopy (CTF), beginning with a retrospective look at CDRH actions related to Computed Tomography (CT). He described CTF and the difficulties of adapting x-ray fluoroscopy standards to CTF, and expressed the view that there has been a renaissance in CT with new applications and new benefits. However, these also have resulted in a high potential for the increase in the amount of radiation patients may receive from these newer technologies. Currently, CDRH is gathering information through the NEXT (Nationwide Evaluation of X-ray Trends) 2000 survey program of CT scanners, and plans on considering future regulatory solutions to the problem.
Dr. Stanley Stern of FDA discussed the Nationwide Evaluation of X-ray Trends (NEXT) 2000 CT survey, which is a cooperative effort between FDA and state radiation control programs. He outlined the survey methodology, and presented information obtained in the past on the principal findings, particularly on air kerma and patient radiation dose. He noted that since 1990 there have been major technical advances in CT such as helical CT, CT Fluoroscopy, and multislice scanners. Consequently, there are also many more examinations which x-ray more of the patient’s body, increasing the potential for higher radiation dose to the U.S. population. The NEXT 2000 survey will involve on-site surveys of approximately 350 facilities, and should yield first-time data regarding the number and types of CT examinations being conducted. A separate, but related, activity is the development of a CT handbook of normalized tissue doses, which should enable the estimation of the radiation dose patients receive from these widely conducted CT examinations. The handbook is expected to be completed within the next 2 years.
The first topic of the second day of the meeting was reengineering of the CDRH radiological health program. Joanne Barron of CDRH reviewed the results of meetings with manufacturers, state regulators, and other stakeholders to explore ways to better use limited FDA resources. Members of TEPRSSC have also been part of this process. Ms Barron stated that stakeholders would like to see reliable product data, analysis of risk perspective, and suggested guidelines for action from FDA. TEPRSSC suggested the agency conduct in-depth characterization of radiation emitting products, analyze trends, and communicate information to states, industry, and the public. The committee also urged FDA to continue conferring with stakeholders to collect information, and that one major goal should be for FDA regulations to provide national uniformity and consistency.
The next presentation was a primer on medical device approval by Dr Kimber Richter, Office of Device Evaluation, CDRH. She provided an overview of the process, including the classification scheme and the differences among the classes. FDA has overlapping statutory authorities for the regulation of medical devices which are also electronic products which emit rediation. Dr. Richter discussed and briefly explained the various product approval pathways for medical devices under the medical device authority, such as 510 (k)s, premarket approval applications (PMAs), and product development protocols (PDPs). She noted that manufacturers may now apply for a modular review, in which sections of the PMA are submitted at different intervals and reviewed independently. Dr. Richter spoke of the impact of the FDA Modernization Act (FDAMA), which directed the FDA to use the least burdensome method of device approval, and also discussed device labeling, including general versus specific intended use, and off-label use of devices.
The final presentation concerned ultrasound diathermy devices. Ms. Joanne Barron explained that FDA is considering whether to move from a mandatory standard to a voluntary standard with regard to these products. She described the operation of regulatory versus consensus standards. Mr. Bruce Herman of the FDA discussed important differences and similarities between the IEC and FDA ultrasound therapy standards. He discussed the application of the standard and the way the standards differ on performance issues such as beam shape, beam area, effective radiating area, modulation, effective intensity, beam non-uniformity ratio, applicator temperature, and ultrasound leakage.
FDA is proposing a pilot program regarding ultrasound diathermy. This would involve formal recognition of the IEC standard, with exceptions, and that manufacturers be given the choice of either adhering to the current FDA mandatory performance standard and associated reporting requirements, or being exempted from these requirements, if they claim conformance to the IEC standard.