Calculation of Stopping Power and Stopping time for Protons in Human Tissues View PDF

The study of the interaction of ionizing radiation (X-rays, electrons, positrons, protons,and heavy ions) with living tissue is of paramount importance in the treatment of cancer because the amount of energy transferred by ionizing radiation to cancer cells will determine the outcome of treatment. Radiation therapy for ions has become common because it can provide High-dose radiation to the target while avoiding adjacent healthy tissues and organs [1].

A charged particle moving rapidly through matter loses energy primarily by ionizing and exciting atoms. An important goal of theoretical understanding of these processes is the prediction of the average rate of energy loss of the particle per unit distance traveled as a function of the particle’s energy. This fundamental quantity is called the stopping powerof the material for that particle. It is often denoted by the symbol -dE/dx and expressed in the units MeV/cm. Dividing the stopping power by the density ρ of the material gives the closely related mass stopping power,- dE/ρdx, which can be expressed in [2] . The stopping power is the most important parameter ofthe energy loss process of energetic ions that is passing through matter. The energy loss of heavy ions is complicated because of the charge-exchange effect which leads to charge-state fluctuations [3]. The electronic stopping is caused by the interaction of ions with the target bound electrons [4]. The lost energy of the ions penetrating the material can occur due to severalprocessesexcitation and ionization of the target atoms, the capture of the electron, ionization or excitation of the projectile [5]. The aim of this research to study mass stopping power for the protons, in tissues (Bone, Muscle (skeletal), Adipose tissue) using Bethe and Bragg equations.