The mass collision energy loss (dE/dX), the mass radiative energy loss (Srad/) and the total mass stopping power of electrons in the energy range of 0.01 MeV up to 1000 MeV has been calculated for Lung, Urea and Skin. The results of the present work for the mass collision stopping power of electrons in Lung, Urea and Skin are in excellent agreement with the standard results given by ESTAR program, where the maximum percentage error between the present calculated values and that of ESTAR program in Lung tissue, Urea and Skin tissue is 0.27%, 0.3% and 0.8% respectively. The mass radiative energy loss of electrons in the same energy range is also calculated using a modified equation, and the results are found to be in very good agreement with the standard published values. The employed modified equation used to calculate the mass radiative energy loss of electrons is valid in the energy range of electrons from 0.01 MeV up to 1000 MeV and gives accurate results. As the results of total stopping power calculation are concerned, they are found in excellent agreement with the published results, where the error is less than 1%.
