Proton and heavy ion radiotherapy: the context and challenges

Protons and heavy ion radiation therapy have proven highly effective against a wide range of cancers and in recent decades there have been rapid advances. Due to the physical characteristics of the Bragg-peak and superior biological properties, proton and heavy ion radiation is able to focus its energy on the tumor while minimizing exposure to surrounding normal tissues and organs, which is expected help enhance the tumor dose and reduce normal tissue damage. In recent years, many studies have explored the efficacy and safety of proton and heavy ion radiotherapy on various malignancies, such as head and neck cancer, lung cancer, esophageal cancer, and liver cancer. The results of these studies enable a better understanding of the characteristics and advantages of proton and heavy ion therapy. (authors)