Simantirakis G, Hourdakis C J, Economides S, Dimitriou P
Greek Atomic Energy Commission, Agia Paraskevi, 15310 Attiki, Greece.
Radiat Prot Dosimetry. 2011 Sep;147(1-2):129-32. doi: 10.1093/rpd/ncr282. Epub 2011 Jul 9.
The purpose of this study is to evaluate image quality of various computed tomography (CT) scanners installed in Greece, as well as to investigate patient doses from common CT examinations. An image quality survey was performed in 44 CT scanners countrywide. The imaging performance of the systems was evaluated by measurements of certain parameters, such as image noise, spatial uniformity, high- and low-contrast resolution and slice thickness accuracy. Moreover, preliminary results of patient dose survey are presented. Concerning image quality, 80 % of the scanners were found to be in compliance with the national legislation and relative international guidelines for all the examined parameters. Weighted CT dose index and dose-length product values for chest and abdomen routine examinations were generally below the dose reference levels (DRLs) suggested by the European Commission. However, some scanners were found to deliver significantly higher doses than the suggested DRL for head routine examinations. Finally, differences in the performance among scanners of the same type and similar age were observed, pointing out the importance of frequent calibration, routine quality control and proper maintenance.
本研究的目的是评估希腊安装的各种计算机断层扫描（CT）扫描仪的图像质量，并调查常见CT检查的患者剂量。在全国44台CT扫描仪上进行了图像质量调查。通过测量某些参数，如图像噪声、空间均匀性、高对比度和低对比度分辨率以及层厚精度，对系统的成像性能进行了评估。此外，还给出了患者剂量调查的初步结果。关于图像质量，发现80%的扫描仪在所有检查参数方面符合国家立法和相关国际准则。胸部和腹部常规检查的加权CT剂量指数和剂量长度乘积值通常低于欧盟委员会建议的剂量参考水平（DRL）。然而，发现一些扫描仪在头部常规检查中提供的剂量明显高于建议的DRL。最后，观察到相同类型和相近使用年限的扫描仪之间性能存在差异，这表明频繁校准、常规质量控制和适当维护的重要性。
