## 2 Survey of Commercial Use of Radioactive Isotopes  
### Radioisotopes Used in Medical Applications  
There is widespread utilization of gamma and beta irradiation and radioactive radionuclides in medical applications, especially for diagnosis (recognition) and healing (treatment) of diverse human situations. Medicine applies nuclear radiation to give rationality about the status of different organs in a human body or to treat such severe disease as cancer. Almost 40 million medical treatments worldwide are carried out yearly, with a strong increasing tendency up to 5% per year [4]. The nuclear radiation provided by industrial radioactive isotopes is also used for the purpose of medical equipment sterilization. There are numerous radioactive isotopes with a large variety of applications in medicine. These include both short- and long-lived nuclides such as \({}^{213}\)Bi (T\({}_{1/2}\) = 43 min) and \({}^{60}\)Co (T\({}_{1/2}\) = 5.27 years), respectively. An intensively growing nuclear medicine operates with diverse sources of nuclear radiation to make possible a justified diagnosis of diseased, affected human organs and to assign proper treatment in the case of serious sicknesses such as cancer. This opens a unique opportunity to obtain a picture of the human body in vitro and enables a quick diagnosis. All imaging devices are driven by decaying radioisotopes. A dose of the specific radioactivity can be delivered to the human body and the special distribution of the activity absorbed in various locations can be analyzed, making use of 2D or 3D pictures. Such radioactive tracers emitting gamma rays are usually short-lived isotopes, for instance, \({}^{99m}\)Tc and \({}^{131}\)I, which can be given by injection or orally. A computer tomography (CT) intensively used worldwide utilizes a gamma radiation source loaded with short-lived isotopes like \({}^{169}\)Yb or \({}^{192}\)Ir. Every organ in the human body acts differently and absorbs mainly specific chemicals. This feature is routinely used in medicine to assign different isotopes of chemical elements for the customized imaging of different organs. For the purposes of a reliable diagnosis, the radioisotopes should have high enough gamma energy that allows them to avoid absorption in the human body and to leave it for further detection. They also must have a relatively short half-life to disappear from the body due to the radioactive decay shortly after screening is finished. In the case of \({}^{99m}\)Tc radioactive decay, the \({}^{99}\)Mo isotope is produced, which is used in almost 80% of the medical treatments over the world [4]. The radioactive isotopes are also used to expose affected human organs, with the goal of controlling or eliminating growing tumor cells (so-called gamma knife radiosurgery). The external source of the gamma irradiation, for example, decaying \({}^{60}\)Co, can be used for the focused exposure of a precise area in the human body. Internal radiotherapy allows locally concentrated radiation by the placing of a compact radioactive source of gamma or better radiation in a specific area in the human body (brachytherapy), and this is becoming the most important and successful tumor treatment. Implant seeds containing \({}^{131}\)I, \({}^{192}\)Ir can be used for short (up to 15 min) in vitro irradiations and \({}^{125}\)I, \({}^{103}\)Pd implants can be used for the permanent treatments of the patients. The \({}^{177}\)Lu isotope with the low-energy beta emission helps in some cases where other treatments fail. Radioactive isotopes \({}^{153}\)Sm or \({}^{186}\)Re are also used with significant success in palliative procedures to relieve pain [4]. Treatments aiming at destroying malfunctioning cells by means of beta radiation (radiotherapy) use \({}^{177}\)Lu and \({}^{90}\)Y [4]. Another industrial-scale field for radioisotope applications is the sterilization of the medical tools as well as heat-sensible products, for instance, solutions and powders for patient treatments.