Ms. Lillian Gill, senior associate director at the Center for Devices and Radiological Health (CDRH) , opened with an update on three issues discussed at past Committee meetings. Ms. Gill updated the Committee on the cooperative research and development agreement (CRADA) CDRH signed with the Cellular Telecommunications and Internet Association (CTIA). Under this agreement, FDA provides research recommendations and oversight for studies funded by CTIA on the health effects of radio frequency emissions from wireless phones. In 2001, CTIA funded three studies which reported on structural changes in the genetic material of blood cells after exposure to wireless phone signals. This year, CTIA funded two studies investigating the best epidemiological tools for assessing exposure to radio frequency emissions from wireless phones.
Ms. Gill discussed CDRH’s efforts to amend the laser product standard because of recent scientific knowledge of laser bio-effects and the desire to harmonize FDA requirements with International Electrotechnical Commission (IEC) requirements. Since the last TEPRSSC meeting, CDRH has been in discussions with the IEC on the use of their copyright-protected standards. For that reason, this proposal is on hold.
Ms. Gill updated the Committee on the concerns expressed during the May 2002 TEPRSSC meeting about the safety of computed tomography (CT) equipment. An FDA working group has suggested three technical features estimated to reduce radiation dose from CT scans by about 50 percent. The CT working group is also considering a number of another approaches to expediting the adoption of up-to-date standards, and in late October they will meet with an IEC working group on this subject.
For the first formal presentation, Howard Cyr, Ph.D., of CDRH’s Office of Science and Technology , advised that the Center has been working on amendments to the performance standards for sunlamp products with the goal of harmonizing FDA standards with widely accepted international standards. Dr. Cyr also discussed recent efforts related to sunlamps in the scientific community, including the Center’s project on measuring changes in the skin, and a project looking at skin types and doses required to produce and keep a tan. He mentioned NTP risk assessments that name sunlamps as a known cause of cancer and the opinions of other epidemiologists and the International Agency for Cancer Research, which concludes that sunlamps are a probable cause of cancer.
Sharon Miller, also representing the Office of Science and Technology, provided a brief history of the amendment process, beginning in 1998 when the Center published an advanced notice of proposed rule-making (ANPRM). This was prompted by concerns about the rising incidence of melanoma in the United States and other countries and its possible relationship to sunlamps, a citizen’s petition to increase enforcement in sunlamp products, an AMA petition to ban sunlamp products, the desire to harmonize FDA sunlamp standards with the IEC standards, changes in sunlamp technology since 1985 (the last time the standard was amended) and the changing knowledge base of ultraviolet radiation effects. Ms Miller then presented the six proposed amendments to the Committee. The first amendment revises the warning label for sunlamps, following the IEC standard except in the final sentence.“Consult your physician” is not in the IEC standard but Center staff suggested its addition. The second proposed amendment requires that the warning label be included in catalogues and other materials, consistent with the laser standard requirement. The third proposed amendment addresses the definition of a manufacturer, and is also consistent with the requirements in the laser standard.
The fourth proposed amendment changes the language dealing with protective eyewear requirements. The UV limits would be the same but the visible light requirements would become more quantitative. At the Center’s suggestion, the IEC has adopted these changes to the visible light requirements in their standard. In addition, Ms. Miller proposed adopting the 5% cap on visible transmittance that has been part of IEC requirement for sunlamp products for several years, with the modification that it only apply to eyewear used in sunbeds with high-pressure lamps exposing the facial area. The use of sunbeds with high-pressure lamps poses a danger for damage to the retina from intense visible light. Proposed amendment 5a replaces the CIELYTLE erythema action spectrum (currently used by FDA) with the IEC/ CIE reference action spectrum for erythema. Proposed amendment 5b changes the value of the minimal erythemal dose (MED) to 200 J/m 2, a value that has been internationally accepted as being appropriate for a person of ‘skin type II’ (the most sensitive skin type that would be expected to use sunlamps). This would effect the timer setting used to meet the exposure schedule.
The sixth proposed amendment changed the replacement lamp code to facilitate an absolute system. The code on the sunlamp would display wattage, one of four reflector codes, and a UV code based on an X/Y designation. The X value represents the absolute erythema-effective output of the lamp, and the Y value represents the ratio of the non-melanoma skin cancer (NMSC)- weighted output in the UVB and UVA regions of the spectrum. Ms. Miller also noted that the Center is working with the IEC to update their standard for lamp measurements and establishing acceptable ranges for suitable lamp replacements.
The next speaker for FDA was Thomas B. Shope, CDRH Office of Science and Technology, who updated the Committee on the proposed fluoroscopic system amendments to the performance standard for diagnostic x-ray systems (21 CFR 1020.30-.33). He noted that he could not yet present the final proposals, as the comment period for the proposed rule ended April 2003. Dr. Shope summarized the comments received after the publication of the proposed rule in December 2002, and noted that any comments the Committee has during this meeting will be considered during final deliberations. Mr. Shope provided background on the amendment, noting that recent developments in the technology and increased radiation output in the 1990s made it clear to the FDA that there was a need for additional dose and exposure information.
Dr. Shope said that suggestions to the proposed amendment urged harmonization with the IEC standard and recommended modifications to some of the definitions. The FDA also received critiques of several of the proposed requirements, including manufacturers’ description of intended uses; the IEC standard of +-50 percent accuracy for dose display; the placement of responsibility for any modifications and upgrading done to existing equipment; and dose display and last image hold feature requirements for mini C-arm systems. Others comments suggested requiring a display of the air kerma rate during irradiation and a continuous display of the cumulative air kerma.
The last formal presentation concerned emerging issues in ionizing radiation security systems and new products appearing on the market since the terrorist attacks of September 11, 2001. Daniel Kassiday, CDRH Ofc of Compliance, noted that airport workers have recently expressed concern about cabinet x-ray systems. The FDA has been working with the Transportation Security Administration (TSA) to help them develop internal policy on how these systems should be used. Mr. Kassiday said that one of the emerging issues in the area of security systems includes the increasing numbers of vehicle and cargo scanners being bought and installed in ports across the nation. These systems use a backscatter image, transmission image, or both. They are either fixed or mobile and are intended to screen vehicles without passengers. One cargo system, however, is also designed to screen people, such as those along a parade route, but it is not yet distributed in the United States. Mr. Kassiday noted this is not a cabinet x-ray system and therefore does not fall under the FDA standard. He added that there are new products nearing release, including portals designed to screen vehicles and passengers, high-energy accelerators for some cargo containers, and machine-produced neutron systems in development. Mr. Kassiday said that FDA is working with NIOSH, U.S. Customs, OSHA, and TSA to create a consensus standard for equipment used around docks and dock workers. He also reported on the backscatter personnel systems currently approved for sale in the United States, as well as a new transmission x-ray system, not yet for sale in the United States, that has prompted FDA to examine the possibility of a need for a mandatory performance standard.
Frank Cerra, Ofc of Science and technology, updated the Committee on personnel security screening systems. He first provided a brief history of TEPRSSC’s previous discussions regarding mandatory standards for backscatter systems and transmission systems, and TEPRSSC’s recommendation in 2002 of a mandatory standard based on ANSI N43.17 dose limitations and performance requirements. Mr. Cerra discussed the new Health Physics Society (HPS)’s position statement and the guidance the FDA sought from the National Council on Radiation Protection and Measurement (NCRP) on personnel security screening. The latter resulted in an NCRP publication, Presidential Report on Radiation Protection Advice: Screening of Humans for Security Purposes Using Ionizing Radiation Scanning Systems. He noted that the recommendations in both the HPS position statement and the NCRP report are consistent with the 2002 TEPRSSC recommendations. The scope of the NCRP report includes a brief review of known risks from radiation exposure; a consideration of screened populations and susceptible subgroups; and dose recommendations. It also addresses the need for operator training, record keeping, equipment testing, and communicating the effects of radiation exposure. Mr. Cerra noted, however, that the report does not address the issue of when the societal benefits outweigh the risks of security screening because the NCRP believed that this issue fell outside of its role.