Abstract Nuclear Medicine is the branch of medicine concerned with the use of radio-nuclides in the study and the diagnosis of diseases, eg. the assessment of organ function, detection and treatment of some diseases or monitoring of treatment’s effects. It provides physiological (not available from other imaging modalities) and diagnostic information. In the other hand, it uses very small amounts of radioactive material (radiopharmaceuticals, RP) that is introduced into the body and acts as a tracer. Information obtained using nuclear medicine techniques is more comprehensive than other imaging procedures because it demonstrates organ function, not just his structure. The result: many diseases (eg, cancer) may be diagnosed much earlier. In this article, will be discussed questions such as “What are RPs?”, “What is the difference between gamma-decay and beta-decay for nuclear medicine?”, “What kind of RPs are there in therapy or diagnosis?”, “How must be the ideal RP?”, “How can we produce RPs?” or “How can we detect the RPs using techniques, as PET?”. Finally, the bone-seeking therapeutic RP will be discussed. In fact, this technique is used on the basis of radionuclide’s particulate emissions (primarily low to intermediate beta emission). Outline 0. 1. 2. 3. 4. 5. 6. 7. 8. 9. Nuclear Medicine Radioactive processes and interaction with matter Radiopharmaceuticals, Reactor-Produced Radionuclides and Generator systems Therapeutic RPs Diagnosis RPs Physical Principles of PET PET RPs Bone-seeking therapeutic RPs Development of new RPs References imaging of the whole body based on certain cellular receptors or functions, as Ga-67 scan, used in PET scan, [1,14]. Diagnostic tests in nuclear medicine exploit the way that the body handles substances…