Calibration of 125I brachytherapy sources in terms of reference air kerma rate
Since 2008 the Physikalisch-Technische Bundesanstalt (PTB) has, as the second National Primary Laboratory in the world and the first in Europe, been offering the calibration of 125I-brachytherapy sources (so-called prostate seeds) in terms of the quantity reference air kerma rate (RAKR). The primary standard used, a large air-filled parallel-plate extrapolation chamber with thin graphite front and back electrodes is presented, and the calibration process, including anisotropy and spectral photon distribution measurements are described. An uncertainty budget for the calibration, dependent on the properties of the source to be measured, is given.
Keywordsbrachytherapy 125I source reference air kerma rate primary standard calibration
Unable to display preview. Download preview PDF.