[Development of radiotherapy--history and future prospects]

There have been two ways in the development of radiotherapy. One is physical development, in which efforts have been made to improve the dose concentration on the tumor while avoiding normal tissue, and the other is biological efforts to increase the radiation sensitivity of tumors. Computer medicine has improved oncological diagnoses and radiation planning, which in turn has made high quality radiotherapy possible. Radiotherapy is superior with regard to organ preservation in the treatment cancer. Elderly patients with cancer should be treated with minimally invasive organ-preserving therapy, and thus radiotherapy has been and will be an important tool for cancer treatment in the past, present and into the next century.