The use of radioactivity in medicine has increased dramatically thus highlighting its relevance in modern Healthcare practices. To effectively utilise radioactive substances it is vital to gain an understanding of the physics of radiation. In this topic, radioactive decay and the penetrative powers of alpha, beta and gamma emissions will be discussed. Issues of safety are of paramount importance when dealing with radioactive substances and this aspect of radiation management will be fully explained. Finally the beneficial uses that radiation therapy can be put to e.g. when diagnosing and treating patients with cancers, will be highlighted and discussed.