the.com/radiotherapy

means Treating disease, especially cancer, by directing controlled doses of ionizing radiation at diseased tissue to destroy or shrink it.

from Built from Latin radius ('ray, spoke of a wheel') plus Greek therapeia ('treatment, healing, service'). The word clicked into place once X-rays and radium were discovered in the 1890s and doctors realized the same rays that could image the body could also be aimed to damage cells — the term followed the science, a plain compound naming a very new idea with very old parts.