Radiotherapy /(rā`dĭ*ŏ*thĕr"ȧ*py̆)/

Ra·di·o·ther·a·py

Radiotherapy

n.
  1. Treatment of disease by means of x-rays or radioactivity. Radiotherapy of cancer is based on the fact that cancer cells are more sensitive to radiation than most other cells in the body. (Med.)