Specific energy distribution within cytoplasm and nucleoplasm of a typical mammalian cell due to various beta radionuclides

The use of beta radionuclides for treatment in radiotherapies leads for a need of better understanding of interactions and local energy depositions of beta particles within tissue and tissue equivalent media. The aim of this work is to determine microdosimetric quantities for various radionuclides. Specific energy, z, and its distribution, $ f(z) $ , mean specific energy, $ bar{z} $ , and its standard deviations, $ sigma left( {bar{z}_{f} } right) $ , were evaluated for typical single cell where nucleus is the cellular region of interest. Three possible positions of radionuclides were taken into account—cellular membrane, cytoplasm and nucleoplasm. Taking these regions as the source of radiation, microdosimetric quantities were calculated for beta emitting radionuclides: ¹⁹¹Os, ¹⁹⁹Au, ¹⁷⁷Lu, ⁶⁷Cu, ⁷⁷As, ¹³¹I, ¹⁸⁶Re, ³²P, ¹⁸⁸Re and ⁹⁰Y. It was found that low range beta emitters have the largest efficiency and can deliver radiation doses up to 1 mGy per decay. Determination of the specific energy and its distribution for radionuclides is a useful start in order to determine beta emitters for a particular radionuclide therapy.