Who invented Radiation Therapy/ Radiotherapy?
I will nominate Emil Grubbe. Wilhelm Konrad Roentgen presented his paper on X-rays in late 1896. By early 1897 everybody and his grandmother was tinkering with x-rays. Grubbe was a medical student who noticed that his skin peeled after exposure. He proposed to his professor that x-rays could be used to treat cancer. There was a patient named Rose Lee (I assume she was not the famed ecdysiast) who had locally invasive breast cancer. She received radiation and improved greatly.
The title of “mother of radiotherapy” is generally attributed to Marie Curie, who was a Polish scientist practising at the turn of the twentieth century. I think you should be careful about saying “invented radiotherapy” as the decay of natural elements is a constant and ongoing process. Marie Curie identified radioactive isotopes and proposed of the idea of using them to treat neoplastic disease. She ultimately died from her dedication to her work, from bone marrow failure. She was a remarkable woman and one certainly reading up about.