A microscopic data comparison of two different Auger electron spectra of iodine-125

Iodine-125 is well known as an effective Auger electron emitter. This property of Iodine-125 is directly due to its decay characteristics which contain two successive Auger electron cascades per decay. So, many Auger electrons are emitted within each Iodine-125 decay. The number of the Auger electrons can reach up to 40-45 when the decay occurs in a condensed phase. For this reason, the microdosimetric data of Iodine-125 are strongly dependent on the real structure of the Auger electron energy spectra used for microdosimetric calculations. A detailed Auger electron spectrum of Iodine-125 was first reported by Charlton and Booz in 1981, and another Auger electron spectrum of Iodine-125 was published by Stepanek et al. in 1996. These spectra exhibit considerable differences. In this study, the microdosimetric data obtained using these spectra separately in the microdosimetric calculation model recently presented by Uenak were compared. It was found that the dose absorbed by a given volume of an absorbing medium, for example, in the nucleus of a cell, was found considerably higher when using the spectrum by Charlton and Booz than when using the spectrum by Stepanek et al