[The ALARA-principle. Backgrounds and enforcement in dental practices].

Optimization of radiation protection began soon after the discovery of X-rays. The optimization-concept has been refined more and more as a result of increa-sing knowledge of radiation and its effect on people. Since 1973 the acronym ALARA (As Low As Reasonably Achievable) has been used to designate the optimization of X-ray doses. For the dentist the ALARA-principle entails the obligation to minimize the radiation dose to patient and surroundings to a level as low as reasonably achievable. Currently in radiology the acronym ALADA is also used: As Low As Diagnostically Acceptable. To establish ALARA goals Diagnostic Reference Levels are employed in medical radiology. These Diagnostic Reference Levels are also being introduced in dental radiology. Practical measures for ALARA/ALADA in dental practice comprise an awareness of the field of view (for all types of imaging, including cone beam computed tomography) exposure time, and relation to anatomy and diagnostic justification, and shielding.