ABSTRACT
Conrad Freund accidentally discovered a new type of rays which have the capability of visualising what is hidden inside the organism. He called them X-rays. Freund concentrated on dermatology because he was convinced that the penetration depth of X-rays was insignificant beyond the skin; he was the first one to apply scientific methods to the development of treatment protocols. Just months after the discovery, the first attempt to treat a breast cancer patient by X-rays was performed by Emil Grubbe, a student at the University of Chicago. Radiation oncologists next started to use shielding blocks to shape the radiation field and reduce the dose delivered to normal tissues and critical organs. After a break during the Second World War when the cyclotron was used for the war effort, research continued in the 1960s. It was the first high LET radiation therapy which was applied clinically with maximum use in the 1970s and 1980s.
