| 臧桂霞,闫淯淳,许书聪,等.婴幼儿胸部数字化X射线摄影曝光参数的优化[J].中华放射医学与防护杂志,2017,37(6):476-480.Zang Guixia,Yan Yuchun,Xu Shucong,et al.Optimization of exposure parameters for chest digital radiography in infants and young children[J].Chin J Radiol Med Prot,2017,37(6):476-480 |
| 婴幼儿胸部数字化X射线摄影曝光参数的优化 |
| Optimization of exposure parameters for chest digital radiography in infants and young children |
| 投稿时间：2017-02-24 |
| DOI：10.3760/cma.j.issn.0254-5098.2017.06.015 |
| 中文关键词: 婴幼儿 数字化X射线摄影 曝光参数 体表入射剂量 铝梯 |
| 英文关键词:Infants and young children Digital radiography Exposure parameter Entrance surface dose Aluminum step-wedge |
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| 中文摘要: |
| 目的 通过优化婴幼儿胸部数字化X射线摄影（DR）曝光参数，在保证图像质量的前提下，降低辐射剂量。方法 选取100例进行胸部X射线检查的婴幼儿为对照组，测量胸部厚度，通过测量铝梯与不同胸厚婴幼儿拍片的灰度值，确定婴幼儿胸厚对应的铝当量。再以铝梯为体模进行曝光，采用自动曝光控制（AEC），测量不同管电压（kV）曝光所显示的铝梯灰阶数及相应的辐射剂量，确定最佳曝光参数。以优化的曝光参数再进行100例拍摄为试验组，比较两组图像质量及辐射剂量。结果 对照组最大胸厚13.5 cm、最小胸厚8.0 cm和平均胸厚（10.6±1.3） cm对应铝当量分别为2.3、1.4和2.0 cm。试验组平均胸厚为（10.1±2.2） cm。在管电压55~65 kV时，设备显示入射体表剂量为0.068~0.056 mGy，曝光指数（EI）为0.60~0.74，在正常范围内，目测铝梯灰阶数8~11级，辐射剂量降至较低水平时，仍能获得满意的图像质量。总结优化婴幼儿胸部DR曝光参数的计算方案，即X射线管焦点到探测器距离（SID）为100 cm时，不使用滤线栅，以胸部厚度（cm）×2+38（常数）设定管电压（kV），毫安秒（mAs）选择0.8至1.0。两组图像质量评分结果差异无统计学意义（P>0.05）。优化后设备显示体表入射剂量平均值为（0.048±0.007） mGy，低于AEC组的（0.066±0.008） mGy，差异有统计学意义（t=16.781，P<0.001）。结论 本研究公式：管电压（kV）=胸部厚度（cm）×2+38（常数），优化了婴幼儿胸部DR曝光参数，图像质量满足临床诊断要求，患儿受到的辐射剂量降低。 |
| 英文摘要: |
| Objective To optimize the exposure parameters and reduce the irradiation dose level in infants and young children during digital radiography (DR) chest radiography under the premise of satisfied image quality. Methods The thoracic thickness of 100 patients were measured.Determined the aluminum equivalent of the thoraxes of the infants and young children by comparing the grayscale value and the aluminum step wedge.Another 100 infants and young children of experimental exposure were performed with the aluminum step wedge as a phantom,under AEC control,kV was the only variant to explore the optimal exposure parameters with dose monitor simultaneously.At last,clinical validation was performed.Images quality was compared with χ2 test.The radiation dose of two groups was compared with t test. Results The maximum,minimum,average thoracic thickness and their correspondent aluminum equivalent were 13.5 and 2.3 cm,8.0 and 1.4 cm,(10.6±1.3) and 2.0 cm,respectively.The average thoracic thickness of experimental group was (10.1±2.2) cm.The range of entrance surface dose was 0.068-0.056 mGy while the tube voltage range was 55-65 kV.The exposure index range was 0.60-0.74.The visual inspection of aluminum step wedge was from grades 8 to 11 with satisfying image quality at lower radiation.The infant chest X-ray photography exposure parameters formula have been optimized,that was kV=thoracic thickness (cm)×2+38(constant),mAs (0.8-1.0) with SID=100 cm,without filter grid.Compare to the conventional parameters,the image quality of new method had no significant differences (P>0.05).The actual average entrance surface dose was (0.048±0.007) mGy,lower than AEC group (0.066±0.008) mGy.The difference was statistically significant (t=16.781,P<0.001). Conclusions The optimized formula kV=thoracic thickness (cm)×2+38(constant),mAs (0.8-1.0) with SID=100 cm was credible for lowering the radiation exposure with good image quality for clinical diagnosis. |
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