Bahadori Amir, Miglioretti Diana, Kruger Randell, Flynn Michael, Weinmann Sheila, Smith-Bindman Rebecca, Lee Choonsik
1 Space Radiation Analysis Group, National Aeronautics and Space Administration, Johnson Space Center, Houston, TX.
2 Department of Public Health Sciences, Division of Biostatistics, School of Medicine, University of California, Davis, CA.
AJR Am J Roentgenol. 2015 Oct;205(4):827-33. doi: 10.2214/AJR.14.14135.
The objective of our study was to develop an automated calculation method to provide organ dose assessment for a large cohort of pediatric and adult patients undergoing CT examinations.
We adopted two dose libraries that were previously published: the volume CT dose index-normalized organ dose library and the tube current-exposure time product (100 mAs)-normalized weighted CT dose index library. We developed an algorithm to calculate organ doses using the two dose libraries and the CT parameters available from DICOM data. We calculated organ doses for pediatric (n = 2499) and adult (n = 2043) CT examinations randomly selected from four health care systems in the United States and compared the adult organ doses with the values calculated from the ImPACT calculator.
The median brain dose was 20 mGy (pediatric) and 24 mGy (adult), and the brain dose was greater than 40 mGy for 11% (pediatric) and 18% (adult) of the head CT studies. Both the National Cancer Institute (NCI) and ImPACT methods provided similar organ doses (median discrepancy < 20%) for all organs except the organs located close to the scanning boundaries. The visual comparisons of scanning coverage and phantom anatomies revealed that the NCI method, which is based on realistic computational phantoms, provides more accurate organ doses than the ImPACT method.
The automated organ dose calculation method developed in this study reduces the time needed to calculate doses for a large number of patients. We have successfully used this method for a variety of CT-related studies including retrospective epidemiologic studies and CT dose trend analysis studies.
我们研究的目的是开发一种自动计算方法，为大量接受CT检查的儿科和成年患者提供器官剂量评估。
我们采用了两个先前发表的剂量库：容积CT剂量指数归一化器官剂量库和管电流-曝光时间乘积（100 mAs）归一化加权CT剂量指数库。我们开发了一种算法，使用这两个剂量库和从DICOM数据中获取的CT参数来计算器官剂量。我们计算了从美国四个医疗保健系统中随机选取的儿科（n = 2499）和成年（n = 2043）CT检查的器官剂量，并将成年器官剂量与通过ImPACT计算器计算的值进行比较。
脑剂量中位数为20 mGy（儿科）和24 mGy（成年），在头部CT研究中，11%（儿科）和18%（成年）的脑剂量大于40 mGy。除了靠近扫描边界的器官外，美国国立癌症研究所（NCI）方法和ImPACT方法对所有器官提供的器官剂量相似（中位数差异<20%）。扫描范围和体模解剖结构的视觉比较显示，基于真实计算体模的NCI方法比ImPACT方法提供更准确的器官剂量。
本研究开发的自动器官剂量计算方法减少了为大量患者计算剂量所需的时间。我们已成功将此方法用于各种与CT相关的研究，包括回顾性流行病学研究和CT剂量趋势分析研究。
