Berkhout W E R
Ned Tijdschr Tandheelkd. 2015 May;122(5):263-70. doi: 10.5177/ntvt.2015.5.14227.
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.
X射线发现后不久，辐射防护的优化工作便随即展开。随着人们对辐射及其对人体影响的了解不断加深，优化概念也日益完善。自1973年起，首字母缩写词ALARA（尽可能合理达到低水平）被用于表示X射线剂量的优化。对牙医而言，ALARA原则要求其有义务将患者和周围环境所受的辐射剂量降至合理可及的最低水平。目前在放射学领域，也使用首字母缩写词ALADA：尽可能低的诊断可接受水平。为确立ALARA目标，医疗放射学采用了诊断参考水平。这些诊断参考水平也正在引入牙科放射学领域。牙科实践中实现ALARA/ALADA的实际措施包括了解视野范围（适用于所有成像类型，包括锥形束计算机断层扫描）、曝光时间、与解剖结构的关系以及诊断依据，还有防护措施。
