Research Committee, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran.
Radiat Prot Dosimetry. 2020 Dec 30;192(3):341-349. doi: 10.1093/rpd/ncaa192.
The main purpose of this pilot study was to assess the regional diagnostic reference level (RDRL) of computed tomography (CT) examinations to optimise medical exposure in five pediatric medical imaging centers in Tehran, Iran where the most frequent CT examinations were investigated. For each patient, CT volume dose indexes (CTDIvol) and dose length product (DLP) in each group were recorded and their third quartile was calculated and set as RDRL. Pediatrics were divided into four age groups (<1; 1-5; 5-10 and 10-15 years). Then, the third quartile values for head, chest and abdomen-pelvic CTs were, respectively, calculated for each group in terms of CTDIvol: 21.3, 24.4, 24.2 and 36.3 mGy; 2.9, 3.2, 3.7 and 5.7 mGy; 3.7, 5.7, 6.3 and 6.8 mGy; and in terms of DLP: 322.2, 390.1, 424.9 and 694.1 mGy.cm; 53.1, 115.2, 145.3 and 167.6 mGy.cm and 128.7, 317.7, 460.2 and 813.8 mGy.cm. Finally, RDRLs were compared with other countries and preceding data in Iran. As a result, CTDIVOL values were lower than other national and international studies except for chest and abdomen-pelvic values obtained in Europe. Moreover, this matter applied to DLP so that other formerly reported values were higher than the present study but European values for chest and abdomen-pelvic scans and also Tehran studies conducted in 2012. Variation of scan parameters (tube voltage (kVp), tube current (mAs) and scan length), CTDIvol and DLP of different procedures among different age groups were statistically significant (P-value < 0.05). The variations in dose between CT departments as well as between identical scanners suggest a large potential for optimization of examinations relative to which this study provides helpful data.
这项初步研究的主要目的是评估伊朗德黑兰五个儿科医学影像中心的计算机断层扫描（CT）检查的区域诊断参考水平（RDRL），以优化医疗照射。在这些中心，对最常见的 CT 检查进行了研究。对于每个患者，记录了 CT 容积剂量指数（CTDIvol）和剂量长度乘积（DLP），并计算了它们的第三四分位数，并将其设定为 RDRL。儿科患者分为四个年龄组（<1 岁；1-5 岁；5-10 岁；10-15 岁）。然后，分别计算了每个年龄组的头部、胸部和腹部-盆腔 CT 的第三四分位数 CTDIvol 值：21.3、24.4、24.2 和 36.3 mGy；2.9、3.2、3.7 和 5.7 mGy；3.7、5.7、6.3 和 6.8 mGy；以及 DLP 值：322.2、390.1、424.9 和 694.1 mGy.cm；53.1、115.2、145.3 和 167.6 mGy.cm；128.7、317.7、460.2 和 813.8 mGy.cm。最后，将 RDRL 与其他国家和伊朗以前的数据进行了比较。结果，除了在欧洲获得的胸部和腹部-盆腔值外，CTDIvol 值低于其他国家和国际研究。此外，这一情况也适用于 DLP，因此以前报告的其他数值高于本研究，但高于欧洲的胸部和腹部-盆腔扫描值，以及 2012 年在德黑兰进行的研究。不同年龄组之间的扫描参数（管电压（kVp）、管电流（mAs）和扫描长度）、CTDIvol 和 DLP 的变化具有统计学意义（P 值<0.05）。不同科室之间以及同一台扫描仪之间的剂量差异表明，相对于本研究提供的有用数据，检查的优化具有很大的潜力。
