title: New National Air-Kerma Standard for Low-Energy Electronic Brachytherapy Sources.
abstract: The new primary standard for low-energy electronic brachytherapy sources for the United States is described. These miniature x-ray tubes are inserted in catheters for interstitial radiation therapy and operate at tube potentials of up to about 50 kV. The standard is based on the realization of the air kerma produced by the x-ray beam at a reference distance in air of 50 cm.
authors.affiliation: National Institute of Standards and Technology, Gaithersburg, MD 20899.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Seltzer
authors.affiliation: National Institute of Standards and Technology, Gaithersburg, MD 20899.
authors.forename: Michelle
authors.initials: M
authors.lastname: O'Brien
authors.affiliation: National Institute of Standards and Technology, Gaithersburg, MD 20899.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Mitch
keywords: air kerma; electronic brachytherapy sources; free-air ionization chamber; primary standard; spectrometry; x rays