Mean absorbed dose calculation at cellular level for targeted radiotherapy using Auger-electron-emitters

Objective\ To calculate the mean absorbed doses at celluar and subcellular levels for uniformly and non\|uniformly distributed Auger electron emitters. Methods\ The energy deposited in cell or nucleus by Auger electrons was analytically calculated using the polynomial representation of energy loss.S\|values were subsequently computed for several target\|source combinations.The absorbed dose and dose distribution were calculated for spherically symmetric radionuclide distributions depending linearly and exponentially on the radial position.The dose profile as a function of the source radial coordinate was also evaluated for typical cell sizes.The contributions of photon radiation to absorbed dose in cells were ignored. Results\ The mean absorbed dose and dose distribution depend largely on the size of target cells,the radiation spectrum and intracellular localization and distribution of radionuclides.The contribution of intranuclear radionuclides to mean absorbed dose was larger than that of extranuclear ones. Conclusion\ Auger electrons can produce high local energy deposition in cells because of their very low energies and extremely short ranges.Our dose calculation method is simple.The results are reliable and can be used in many fields.