Positron CSDA Range and Stopping Power Calculations in Some Human Body Tissues by Using Lenz Jensen Atomic Screening Function

Abstract

In this study, for some human body tissues, positron stopping power (SP) values were presented, being valid for low and intermediate positron energies. In addition, calculation of the continuous slowing down approximation (CSDA) range from the stopping power is also made. Calculation of the CSDA range for some human body tissues: adipose tissue, skeletal muscle, skin, and soft tissue have been introduced for incident positron in the energy range 20 eV to 10 MeV. The range of positron has been calculated within the continuous slowing down approximation using modified Rohrlich and Carlson formula of stopping power. The calculated results of the SP and CSDA range values for positrons in some materials, such as adipose tissue, skeletal muscle, skin, and soft tissue in the energy range from 20 eV to 100 MeV are found to be in good agreement to with the Penelop 2014 code results above 0.4 keV energies. It makes more meaningful results than penelope 2014 for under 0.4 kev energies. In this work, a model is suggested for the calculation of SP and CSDA ranges for incident positrons on some human body tissues. Simple analytical expressions for the effective number of positrons and effective mean excitation energy (EMEE) and the positron SP have been derived which are suitable for intermediate energies. The results from this study of stopping powers of some humanbody tissues for especially low energy positrons should be useful in PET, diagnostics, and therapy with nuclear radiation.