Smith A B, Dillon W P, Gould R, Wintermark M
Department of Radiology, Neuroradiology Section, University of California, San Francisco, CA 94143-0628, USA.
AJNR Am J Neuroradiol. 2007 Oct;28(9):1628-32. doi: 10.3174/ajnr.A0814. Epub 2007 Sep 24.
Within the past 2 decades, the number of CT examinations performed has increased almost 10-fold. This is in large part due to advances in multidetector-row CT technology, which now allows faster image acquisition and improved isotropic imaging. The increased use, along with multidetector technique, has led to a significantly increased radiation dose to the patient from CT studies. This places increased responsibility on the radiologist to ensure that CT examinations are indicated and that the "as low as reasonably achievable" concept is adhered to. Neuroradiologists are familiar with factors that affect patient dose such as pitch, milliamperes, kilovolt peak (kVp), collimation, but with increasing attention being given to dose reduction, they are looking for additional ways to further reduce the radiation associated with their CT protocols. In response to increasing concern, CT manufacturers have developed dose-reduction tools, such as dose modulation, in which the tube current is adjusted along with the CT acquisition, according to patient's attenuation. This review will describe the available techniques for reducing dose associated with neuroradiologic CT imaging protocols.
在过去20年里，CT检查的数量几乎增长了10倍。这在很大程度上归因于多排探测器CT技术的进步，该技术现在能够实现更快的图像采集并改善各向同性成像。CT检查使用的增加，再加上多探测器技术，导致CT检查给患者带来的辐射剂量显著增加。这使得放射科医生肩负起更大的责任，要确保CT检查是必要的，并坚持“合理尽可能低”的原则。神经放射科医生熟悉影响患者剂量的因素，如螺距、毫安、千伏峰值（kVp）、准直，但随着对剂量降低的关注度不断提高，他们正在寻找进一步降低其CT检查方案相关辐射的其他方法。为应对日益增加的担忧，CT制造商开发了剂量降低工具，如剂量调制，即根据患者的衰减情况，在CT采集过程中调整管电流。本综述将描述与神经放射学CT成像方案相关的可用剂量降低技术。
