From the Department of Medical Imaging, St Michael's Hospital, 30 Bond St, Toronto, ON, Canada M5W 1W8 (K.M., T.D., B.G.G.); and Department of Neuroscience (I.L.) and Faculty of Medicine, Department of Medical Imaging (T.D., B.G.G.), University of Toronto, Toronto, Ont, Canada. K.M., T.D., B.G.G. supported by St Michael's Hospital Alternative Funding Plan Innovation Fund (SMHAIF-094).
Radiology. 2015 Aug;276(2):507-17. doi: 10.1148/radiol.2015141520. Epub 2015 Apr 20.
To retrospectively evaluate radiation optimization efforts over 4 years for three computed tomography (CT) protocols and to determine institutional (local) diagnostic reference levels for prospective tracking by using automated radiation dose index monitoring software.
Approval for this retrospective observational study was obtained from the hospital research ethics board, and the need to obtain informed consent was waived. The study followed a 48-month radiation dose optimization effort in a large academic inner-city trauma and quaternary referral center. Exposure according to equipment, protocol, and year (2010-2013) for adult patients was determined for routine unenhanced head CT examinations, CT pulmonary angiography examinations, and CT examinations for renal colic. Mean exposure (as volume CT dose index [CTDIvol] and dose-length product [DLP]) was averaged to establish local diagnostic reference levels. Means and 75th percentiles for 2013 were compared with findings from surveys in Canada and diagnostic reference levels for similar protocol types internationally. Student t tests were performed to assess significance between annual means, and χ(2) tests were performed for changes in categoric variables.
There were 36 996 examinations in 25 234 patients. There was an average exposure reduction of 22% for CTDIvol and 13% for DLP from 2010 to 2013. In 2013, mean CTDIvol for routine head examinations was 50.8 mGy ± 3.7 (standard deviation), 11.8 mGy ± 5.6 for CT pulmonary angiography examinations, and 10.2 mGy ± 4.2 for renal colic CT examinations, while mean DLP was 805.7 mGy · cm ± 124.3, 432.8 mGy-cm ± 219.9, and 469.4 mGy · cm ± 209.2, respectively. The mean CTDIvol and DLP in 2013 were at or close to identified reference values; however, additional optimization is required to reach "as low as reasonably achievable" values for all examinations.
Automated methods of radiation dose data collection permit a detailed analysis of radiation dose according to protocol and equipment over time. Radiation dose optimization measures were effective, but their full value may be realized only with changes in internal processes and real-time, prospective data monitoring and analysis.
使用自动辐射剂量指数监测软件，回顾性评估 4 年来 3 种 CT 方案的辐射优化工作，并确定机构（本地）诊断参考水平以进行前瞻性跟踪。
本回顾性观察研究获得了医院研究伦理委员会的批准，并豁免了获得知情同意的需要。该研究在一家大型学术性市区创伤和四级转诊中心进行了为期 48 个月的辐射剂量优化工作。对 2010 年至 2013 年成人患者的常规增强头部 CT 检查、CT 肺动脉造影检查和肾绞痛 CT 检查，根据设备、方案和年份（2010-2013 年）确定了暴露情况。平均暴露量（以体积 CT 剂量指数[CTDIvol]和剂量长度乘积[DLP]表示）用于确定本地诊断参考水平。比较 2013 年的平均值和第 75 百分位数与加拿大调查结果和国际类似方案类型的诊断参考水平。采用学生 t 检验评估年度均值之间的显著性差异，采用卡方检验评估分类变量的变化。
共有 25234 例患者的 36996 次检查。与 2010 年相比，2013 年 CTDIvol 和 DLP 的平均暴露量分别降低了 22%和 13%。2013 年，常规头部检查的平均 CTDIvol 为 50.8 mGy ± 3.7（标准差），CT 肺动脉造影检查为 11.8 mGy ± 5.6，肾绞痛 CT 检查为 10.2 mGy ± 4.2，而平均 DLP 分别为 805.7 mGy·cm ± 124.3、432.8 mGy-cm ± 219.9 和 469.4 mGy·cm ± 209.2。2013 年的平均 CTDIvol 和 DLP 值处于或接近已确定的参考值；然而，所有检查仍需要进一步优化，以达到“尽可能低”的可实现值。
辐射剂量数据采集的自动化方法可根据协议和设备随时间对辐射剂量进行详细分析。辐射剂量优化措施是有效的，但只有通过改变内部流程以及实时、前瞻性的数据监测和分析，才能充分发挥其价值。
