Shah Chintan, Jones A Kyle, Willis Charles E
Department of Bioengineering, University of Toledo, Toledo, Ohio 43606, USA.
Med Phys. 2008 Aug;35(8):3616-25. doi: 10.1118/1.2952361.
Radiographic techniques are devised on the basis of anatomic dimensions. Inaccurate dimensions can cause radiographs to be exposed inappropriately and patient radiation exposures to be calculated incorrectly. The source of anatomic dimensions in common usage dates back to 1948. The objective of this study was to compare traditional and modern anthropometric data, use modern dimensions to estimate potential errors in patient exposure, and suggest modified technique guidelines. Anthropometry software was used to derive modern anatomic dimensions. Data from routine annual testing were analyzed to develop an x-ray generator output curve. Published tabulated data were used to determine the relationship between tissue half-value layer and kilovoltage. These relationships were used to estimate entrance skin exposure and create a provisional technique guide. While most anatomic regions were actually larger than previously indicated, some were similar, and a few were smaller. Accordingly, exposure estimates were higher, similar, or lower, depending on the anatomic region. Exposure estimates using modern dimensions for clinically significant regions of the trunk were higher than those calculated with traditional dimensions. Exposures of the postero-anterior chest, lateral chest, antero-posterior (AP) abdomen, male AP pelvis, and female AP pelvis were larger by 48%, 31%, 54%, 52%, and 112%, respectively. The dimensions of bony regions of the anatomy, such as the joints and skull, were unchanged. These findings are consistent with the idea that anatomic areas where fat is deposited are larger in the modern U.S. population than they were in previous years. Exposure techniques for manual radiography and calculations of patient dose for automatic exposure control radiography should be adjusted according to the modern dimensions. Population radiation exposure estimates calculated in national surveys should also be modified appropriately.
放射技术是根据解剖学尺寸设计的。尺寸不准确会导致射线照片曝光不当，以及患者辐射剂量计算错误。常用的解剖学尺寸来源可追溯到1948年。本研究的目的是比较传统和现代人体测量数据，使用现代尺寸估计患者照射中的潜在误差，并提出改进的技术指南。使用人体测量软件得出现代解剖学尺寸。分析常规年度测试的数据以绘制X射线发生器输出曲线。使用已发表的表格数据确定组织半值层与千伏之间的关系。这些关系用于估计皮肤入口照射量并创建临时技术指南。虽然大多数解剖区域实际上比以前显示的更大，但有些区域相似，还有一些区域更小。因此，照射量估计值会更高、相似或更低，这取决于解剖区域。使用现代尺寸对躯干临床重要区域的照射量估计高于使用传统尺寸计算的结果。后前位胸部、侧位胸部、前后位腹部、男性前后位骨盆和女性前后位骨盆的照射量分别增加了48%、31%、54%、52%和112%。解剖结构中的骨性区域，如关节和颅骨，尺寸没有变化。这些发现与现代美国人群中脂肪沉积的解剖区域比前几年更大的观点一致。手动放射摄影的照射技术以及自动曝光控制放射摄影的患者剂量计算应根据现代尺寸进行调整。全国调查中计算的人群辐射剂量估计也应适当修改。
