FIGURE 90.11 The effect of distance on radiation exposure from a point source of radiation Recognition Radiation exposures can be recognized by understanding three questions: (i) Who is likely to be affected by a radiation exposure or accident? (ii) What are the likely sources of radiation? and (iii) What are the likely injuries? The people most likely to be involved in a radiation exposure event are individuals whose work involves radiation Other individuals who may be exposed to radiation include members of the general public who inadvertently come into contact with a radiation hazard, for example, the population surrounding a nuclear powerplant, those who are intentionally poisoned, and patients who have undergone medical procedures (e.g., fluoroscopy or radiation therapy) To cause a significant radiation injury, an intense radiation source is needed The four major types of possible intense radiation sources are listed in Table 90.12 Because of their various physical properties, different sources are likely to cause different types of radiation injuries Radiation induces injury either through exposure or contamination Because patients exposed to radiation not have radioactive elements on or in them, they not emit radiation and can be treated without any additional precautions on the part of healthcare workers Two types of injury from radiation exposure are