Production of Radioactivity in Animal Tissues by High-Energy X-Rays

Introduction THE photo-disintegration of atomic nuclei by high-energy X-rays is well known ; but there seems previously to have been no record of the production of radioactivity in animal tissues. In view ofthaocvious radiobiological and medical importance of any such phenomena, we have carried out pre-lirimiary observations on rat tissues exposed to beams of X*rays from the Royal Cancer Hospital synchrotron. It was found that there is no difficulty in demonstrating induced activity in the tissues, and we have therefore attempted to find out what elements are responsible for the activity, the order of radioactivity induced, and to assess its biological significance.