Women undergoing mammography exams at accredited U.S. facilities can be assured of receiving proper X-ray exposures thanks to the National Institute of Standards and Technology’s (NIST’s) dedicated calibration facility for mammographic X-rays.
The facility allows the operators and inspectors of more than 10,000 U.S. mammography centers to trace the accuracy of X-ray exposure measurements to the primary mammography X-ray standards at NIST. The calibration facility was established in Building 245 to assist the U.S. Food and Drug Administration (FDA) in implementing the Mammography Quality Standards Act of 1992. This law requires the FDA to set up a certification and inspection program for all U.S. mammography clinics. The instruments used by the FDA inspectors to measure the X-ray exposure from the clinical units are calibrated using standards traceable to NIST’s reference X-ray beams. In addition, proficiency tests are offered to key calibration laboratories and X-ray instrument manufacturers to ensure they continue to use the standards properly and to their fullest extent.
The recent advent of digital mammography requires the use of tungsten anode X-ray beams, and work to determine appropriate calibration schemes for these beams is underway.