Proton therapy is a type of radiation therapy that uses proton beams to treat cancer. However, there are other terms that can be used interchangeably for proton therapy. For instance, particle therapy refers to the use of particles, such as protons and ions, to treat cancer. Also, heavy ion therapy and carbon ion therapy are alternatives to proton therapy, especially in treating deep-seated tumors. Moreover, charged particle therapy and hadron therapy are used as synonyms for proton therapy. Finally, active scanning, pencil beam scanning, and spot scanning are specialized techniques used in administering proton therapy, making the treatment precise and efficient. Ultimately, all these terms refer to the same principle, which is to target cancer cells more precisely and limit the dose to surrounding healthy tissues.