X-rays are produced by artificial radiation sources (radiogenic machines). Gamma rays, on the other hand, are generated by the decay of radioisotopes: atoms characterized by the property of spontaneously emitting ionizing radiation. In this decay process, the nucleus of an element transforms into the nucleus of a different element or reaches a lower energy state. Ionizing radiation sources can be divided into:
- Radiogenic machines that, by accelerating elementary charged particles (for example, electrons), generate radiation beams (for example, X-rays);
- sealed sources, that is, radioactive materials (radioisotopes) sealed in an inactive enclosure that has sufficient resistance to prevent, under normal operating conditions, the dispersion of radioactive materials exceeding the values established by applicable good practice standards. If the source composed of radioactive materials does not meet the definition of a sealed source, it is referred to as an unsealed source.
Note. Sealed and unsealed sources not only emit gamma rays but can also emit charged particles such as protons, electrons, and alpha particles that are capable of ionizing human tissues.
Where ionizing radiation sources are present in the work environment, the risk assessment from exposure to ionizing radiation must be carried out with the assistance of the Radiation Protection Expert appointed by the Rector. The Radiation Protection Expert:
- design the workplaces, any protective barriers, and signage, and establish the procedures to follow so that workers and any third parties are exposed to the minimum extent possible;
- limit the number of exposed individuals, compatible with work requirements;
- limit the exposure time of the worker;
- assess the exposure levels of the worker through environmental and/or personal monitoring.
Furthermore, the Radiation Protection Expert, in light of the tasks declared by the individual worker, the Head of the Facility, and the Activity Supervisor, and based on the characteristics of the sources used within the scope of the task, classifies workers as exposed or not exposed and classifies the workplaces so that exposed workers are subjected to appropriate physical and medical monitoring, and access to the affected workplaces is limited, controlled, and marked.
IMPORTANT: WHAT TO DO whenever you intend to purchase, decommission, or transfer a new ionizing radiation source to another laboratory
Whenever you intend to hold and use a new source, decommission it, or move it, it is necessary to involve the Control Authorities, and for certain types of sources, a simple notification is not sufficient; instead, you must submit a request for a Clearance to Use to the Control Authorities. This process requires some time before the Clearance is issued by the designated authorities. The regulation to refer to is Legislative Decree 101/20 and subsequent amendments.