Application of automatic vertical positioning software to reduce radiation exposure in multidetector row computed tomography of the chest
Application of automatic vertical positioning software to reduce radiation exposure in multidetector row computed tomography of the chest
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DOI：
10.1097/rli.0b013e318169005e
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发表时间：
2008-06-01
影响因子：
6.7
通讯作者：
Kalra, Mannudeep K.
中科院分区：
文献类型：
--
作者：
Li, Jianhai;Udayasankar, Unni K.;Kalra, Mannudeep K.
目的：探讨自动垂直定位(AVP)软件在胸部多层螺旋CT中降低辐射剂量的作用。材料与方法：连续243例胸部多层螺旋CT患者，年龄20~93岁，平均54岁。这项研究在放弃知情同意的情况下得到了我们的机构审查委员会的批准。技术人员最初通过使用激光制导系统和患者表面解剖调整床面高度(垂直定位)来将患者放置在龙门架上。然后使用AVP软件来确定患者的真实垂直位置，基于匹配个体患者整个胸部的平均质心(质心)，该质心由横向投影与机架等中心和领结过滤器的中心相匹配。然后计算了这种基于衰减的垂直定位所导致的表面辐射剂量的减少。结果：95.5%(232/243)的患者垂直错位距离平均为33.2+/-1.1 mm(5.1~97 mm)，95.5%(232/243)的患者垂直错位距离为33.2±1.1 mm。在错位患者中，97%(225/232)的患者垂直错位在等中心以下，平均距离为33.8+/-1.1转弯(5.1~97 mm)，3%(7/232)的患者垂直错位在等中心以上，平均距离12.7+/-2.8 mm(6~28 mm)。AVP软件的表面辐射剂量平均减少19%+/-1%(范围1%~46.6%)。垂直错位距离与AVP软件促进的体表辐射剂量减少有很强的相关性(r(2)=0.90，P&0.001)。结论：AVP软件可以帮助患者优化垂直体位，从而大幅降低体表辐射剂量。
Objective: To determine the effect of automatic vertical positioning (AVP) software on radiation dose reduction in multidetector row computed tomography of the chest.Materials and Methods: Two hundred forty-three consecutive patients (mean age, 54; range, 20-93 years), who underwent 64-slice multidetector row computed tomography of the chest from November 2005 to April 2006, were included in this study. This study was approved by our institutional review board with waiver of informed consent. Technologists initially positioned the patient in the gantry by adjusting the table height (vertical positioning) using a laser guidance system and patient surface anatomy. AVP software was then used to determine the true vertical positioning of the patient based on matching the individual patient's mean centroid (center of mass) throughout the chest as determined by the lateral projection with the gantry isocenter and center of the bow-tie filter. The resultant reduction in surface radiation dose with this attenuation-based vertical positioning was then calculated. Software-determined changes in patient vertical positioning and resultant radiation dose savings were analyzed using the t test and Pearson correlation statistics.Results: Vertical positioning of the patients by the technologist differed from AVP with the bow-tie filter in 95.5% (232 of 243) of patients with an average vertical mispositioning distance of 33.2 +/- 1.1 mm (range, 5.1-97 mm). Among mispositioned patients, 97% (225 of 232) were vertically mispositioned below the isocenter with a mean distance of 33.8 +/- 1.1 turn (range, 5.1-97 mm) and 3% (7 of 232) patients were vertically mispositioned above the isocenter, with a mean distance of 12.7 +/- 2.8 mm (range, 6-28 mm). The average surface radiation dose reduction with AVP software was 19% +/- 1% (range, 1%-46.6%). There was a strong correlation between vertical mispositioning distance and the surface radiation dose reduction facilitated by AVP software (r(2) = 0.9, P < 0.001).Conclusion: AVP software can help in optimum patient vertical positioning leading to substantial reduction in surface radiation dose.