Cellular dosimetry: absorbed fractions for monoenergetic electron and alpha particle sources and S-values for radionuclides uniformly distributed in different cell compartments

Abstract

The importance of cellular dosimetry in both diagnostic and therapeutic nuclear medicine is becoming increasingly recognized.

Methods: Experimental range-energy relations for electrons and alpha particles, along with derived geometric reduction factors, are used to calculate cellular absorbed fractions for these radiations. The resulting absorbed fractions are employed to calculate cellular S-values for several radionuclides.

Results: Cellular absorbed fractions for monoenergetic electron sources with energies ranging from 0.1 keV to 1 MeV, distributed uniformly in the source region, are calculated for several target<--source combinations including cell<--cell, cell<--cell surface, nucleus<--nucleus, nucleus<--cytoplasm and nucleus<--cell surface. Similar data are also provided for monoenergetic alpha particle sources with energies ranging from 3 to 10 MeV. S-values are also conveniently tabulated for 32P, 35S, 86Rb, 89Sr, 90Y, 91Y, 114mIn, 131I. Auger-electron-emitters 51Cr, 67Ga, 99mTc, 111In, 123I, 125I, 201TI, 203Pb and the alpha emitter 210Po. In addition, S-values are given for radionuclides in the 212Pb decay series, including 212Pb, 212Bi and 212Po. Both absorbed fractions and S-values are supplied for a number of different size cells and cell nuclei.

Conclusions: With the absorbed fractions and S-values in hand, along with experimentally determined information on the biokinetics and subcellular distribution of the radionuclides, the cellular self-absorbed dose can be conveniently calculated.