[Occupational exposure to radiation].

Since the discovery of X-rays, over exposures and radiation in juries have been reported in both patients and persons exposed in the course of their professional duties. Each year, more than 2,500 million diagnostic radiological examinations, 32 million nuclear medicine examinations or treatment procedures and 5.5 million radiotherapy sessions are performed world wide. Despite all precautions, avoidable incidents and accidents occur through out the world every year, albeit with low frequency. Where as diagnostic radiology is generally safe for patients and staff, intervention al procedures (e.g. coronary artery dilatations) involve the risks of occupational over exposure and of skin injuries to patients. In nuclear medicine, radiation protection is focused on the introduction of new procedures with beta-emitters, for example. The increasing frequency of positron emission tomography (PET) requires a special focus on shielding measures. In radiotherapy, occupational over exposure caused by mal functions and accidents is relatively rare.