Interaction of proton beam with human tissues in proton therapy

Proton therapy is an effective and safe method to treat tumors in human body. Instead of conventional radiation (X-rays), this technique uses a heavy charged particles (protons) to treat cancer. This chapter reviews the basic aspects of the physics of proton therapy, including proton beam properties, proton interaction mechanisms, and radiation effects induced in the human tissue. A more highly conformal technique of proton therapy called “pencil beam scanning”, based on intensity-modulated proton therapy (IMPT), will be also developed. The uncertainty in the determination of the relative biological effectiveness (RBE) will also be discussed in light of recent experimental results. We conclude the chapter by discussing future developments and potential challenges of proton therapy.