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Program Area: Radiological Health and Safety Program

Scope: The scope of this program is to provide laboratory and technical support to the Center’s Radiological Health mission. FDA serves as a reference laboratory in the national measurement system for safety from radiation emitting electronic products. OSEL maintains measurement and calibration facilities for x-ray, laser, non-coherent optical sources, and microwave measurements. These calibration labs provide traceability for standards enforcement measurements, facilitate uniformity of measurements, and provide metrology expertise for pre and post market issues.

Background: The program began in the early seventies with the implementation of mandatory performance standards for electronic product radiation. With nationwide compliance testing of x-ray equipment it was necessary that measurements be consistent. The program provided field inspectors with uniform instrumentation which was accurate but simple to use. A state-of the art calibration laboratory was developed in order to provide the Bureau of Radiological Health (later CDRH) with a large-volume of high-quality, low-cost calibrations at a time when such calibrations where not available elsewhere. Operating its own calibration lab gave the Bureau complete and independent control over the traceability of field measurements. This facilitated the validation of compliance measurements when they were challenged, provided uniformity of data for analysis, and eliminated possible conflicts of interest.

In the nineties, with the implementation of MQSA, the laboratory's workload increased as FDA began annual inspections of mammography facilities. The laboratory was instrumental in the development of the national calibration standard for mammography x-ray beams maintained by NIST. The CDRH X-ray Calibration Laboratory contributed to many standards for calibrations of ionizing radiation measuring instruments. In 1992 the laboratory was the first to receive accreditation from NIST's National Voluntary Laboratory Accreditation Program for this type of calibration. Through the years the laboratory has provided FDA and agreement-state agencies with reliable ionizing radiation calibrations and metrology support.

Program Description: Radiation safety continues to be a significant concern for the Center. To help address this topic, OSEL maintains measurement and calibration facilities for x-ray, laser, non-coherent optical sources, and microwave measurements. Each year FDA is responsible for the inspections of over 11,000 mammography facilities under the Mammography Quality Standards Act (MQSA). In addition, about 1,600 installations of general radiographic equipment are inspected against the mandatory performance standards mandated by the Radiation Control for Health and Safety Act (RCHSA). FDA also tests a number of industrial x-ray facilities each year. These inspection and testing programs involve measurements of ionizing radiation. OSEL supplies OC, OCER, ORA, and Agreement States with calibrated x-ray instruments and supplies for the various compliance inspection programs, support for special measurements as needed, such as measuring the ionizing radiation output from personnel security scanners, night vision devices, radioactive contamination of medical or consumer products, and CT beam profiles, and technical consultation. Traceability of measurements is achieved through the operation of a standard laboratory accredited by the National Voluntary Laboratory Accreditation Program (NVLAP).

In addition to ionizing radiation instrument calibrations, OSEL provides laboratory measurements and calibrations of light meters, laser measurement instrumentation, and microwave oven instruments for field enforcement of FDA performance standards. OSEL staff also provides pre- and post-market evaluations of selected products for compliance with FDA radiation standards.

The CDRH radiation measurement and calibration laboratories are internationally respected, and laboratory staff contribute significantly to the development of measurement protocols of new standards. For example, laboratory staff have been instrumental to the establishment of the national standard for mammography x-ray calibrations and continue to work closely with NIST. In addition, staff have been closely involved in the effort to align the FDA standards for Lasers and Sunlamps with their international equivalents. The measurement and calibration program has been shown to be a cost effective method of providing a large volume of high quality calibrations for a nationwide network of inspectors. FDA can be assured that compliance measurements are traceable to national standards. Traceability can be readily verified, because FDA is the sole custodian of the traceability chain. The laboratory's services are used for leveraging state agencies to test newly installed radiological equipment against FDA requirements, resulting in hundreds of additional inspections per year. The program allows both FDA and the states to avail themselves of traceable calibrations, which are independent of regulated industry, thus eliminating potential conflicts of interest.

Relevance to FDA’s and CDRH’s Mission Program, and the Public Health Impact:

This program allows the CDRH to fulfill its responsibilities for monitoring the safety of electronic products that emit potentially hazardous levels of radiation. For example, inspection of mammography facilities mandated by MQSA as well as of medical diagnostic radiographic equipment require the use of calibrated radiation monitoring equipment provided by this program. The program provides expertise for quantifying radiation emissions from emerging technologies and new products.

Five Year Objectives:

In addition to the present level of support, the x-ray program expects increased activity in support of the field programs during the next five years. The increases are necessitated mainly by two new requirements: 1) New metrology support and calibration needs due to proliferation of x-ray security screening systems; 2) Need to replace the main field instrument for testing medical diagnostic x-ray equipment and adaptation to states as partnership customers. Calibration support for the MQSA and Diagnostic X-ray field inspection programs is expected to continue at or near the present level.

Necessary new activities in support of OC and ORA for screening system safety include: working with instrument manufacturers to produce field instruments capable of making appropriate radiation measurements, developing new calibration techniques and procedures for these instruments, working with OC in the development of field testing procedures, increased number of routine calibrations of survey instruments in low intensity x-ray fields, and involvement in the development of new performance standards for non-medical x-ray equipment.

The main instrument that is used in the field compliance procedure for medical diagnostic and mammography x-ray equipment, the Radcal 1015, is based on old technology that is no longer cost-effective. A replacement instrument needs to be incorporated into the Diagnostic and MQSA field testing programs. Providing the calibration service to the states as a successful leveraging tool requires an increase in the types of instruments accepted for calibration. It also presents new bookkeeping and logistics challenges. New program activities will involve testing instruments, writing specifications, developing and implementing new calibration facilities and writing new procedures.

The x-ray program also expects to complete the upgrade of all its facilities to modern computer equipment and to install new x-ray equipment for non-invasive kV meter calibrations.

For the Laser program, instrumentation has not been upgraded to keep pace with innovation in the industry, both in laser products available in the consumer market and in the medical device market. In order to address this need, a multi-year program to modernize and upgrade the laser measurement and calibration capabilities is needed. Up-to-date measurement equipment is needed to provide support to the Office of Compliance and the Office of Device Evaluation when testing is needed to verify product classification or to obtain data for risk assessment of new laser devices. Amendments to the FDA laser standard will implement new requirements which will necessitate changes in measurement techniques.

Projects:

1. Calibrations of X-ray Instruments
2. Laboratory Quality and Accreditation Activities
3. IR Product Compliance Support
4. Calibration Laboratory Updates
5. Measurements and Standards for Security Screening Systems
6. Optical Radiation Safety
7. Diagnostic X-ray Dose Reporting System for the U.S.

Updated January 27, 2005

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