Activity characterization of pure-β-emitting brachytherapy sources

A generalized approach for characterizing the activity content of sealed β-emitting sources has been developed, and was employed to establish National Institute of Standards and Technology based activity standardizations for three different types of intravascular brachytherapy sources. Initial ionization current measurements on the sources prior to destructive assays led to the establishment of calibration factors that can be used for subsequent non-destructive measurements of similar sources. Activity characterizations are needed to unequivocally relate theoretic absorbed-dose modeling results to dosimetric measurements, as well as to establish production and quality controls by the source manufacturers, and to satisfy the requirements of various governmental regulatory authorities.