Transportation Processes Of Ions In Heavy Ion Cancer Therapy

With the increasing number of people who suffered from cancer, the researches of the curative methods to cancers become more and more important. Researchers have found many ways to deal with cancers, and the heavy ion beam cancer therapy is the most prospective one. Therefore, there are very important academic and realistic meanings to study the physics processes in ion beam cancer therapy.To the study of the physics processes in ion beam cancer therapy, the main goal is to investigate the transportation processes of the incident ion moving through the target tissue. Impact ionization is an important process in radiation damage of biological. The secondary electrons caused by the impact ionization process are the main reason which can lead to DNA double stand breaks (DSBs) of cancer cells. Therefore, the research to impact ionization is helpful to improve the heavy ion beam cancer therapy theoretically.In this paper, we study the theories of different physics processes which may be responsible for biological damage induced by an single ion propagating through living tissue. The most work is as follows:1. In this paper, we introduce the basic physical theory and models in ion beam radiations, and provide the basis and support of the follow works.2. In order to build the theory model, for simple, we take single proton and carbon ion (12C6+) to be the incident particles, and take pure water instead of living tissue. We use the semi-empirical Rudd's model to investigate the cross sections of ionization processes, and then study the energy on the trajectory of particles. At last, we discuss the relationships between the linear energy transfer (LET) of incident particles and the penetration depth, and finally find their Bragg peaks.3. Study and compare the two pictures of LET, discuss which particle is better for heavy ion cancer therapy.