Boone J M, Duryea J, Moore E H
Department of Radiology, University of California, Davis 95817, USA.
Radiology. 1995 Sep;196(3):845-50. doi: 10.1148/radiology.196.3.7644654.
To determine the feasibility of using the filter wheel equalization (FWE) technique for radiographic equalization in chest radiography.
An FWE system with two rotating wheels (one for each lung) with 25 lung-shaped, 1.0-mm-thick copper templates was constructed. Preexposure images were acquired; the computer used these images to select and position templates for each lung. An equalized radiograph was then produced. Radiographs were acquired in two male volunteers (both 33 years of age) and in a phantom.
Optical densities in the lungs and nonlung areas on a conventional phantom radiograph were 2.07 and 0.55, respectively; after equalization, the corresponding optical densities were 2.06 and 1.42. Outside the lungs, radiographic contrast (difference in optical density) increased threefold; in the lungs, there was a very small decrease in radiographic contrast due to beam hardening. Well-equalized and relatively artifact-free radiographs were obtained with a 20-msec exposure time.
The FWE system was shown in the laboratory to be feasible.
确定在胸部X线摄影中使用滤光轮均衡（FWE）技术进行X线摄影均衡的可行性。
构建了一个FWE系统，该系统有两个旋转轮（每个肺一个），带有25个肺形、1.0毫米厚的铜模板。采集预曝光图像；计算机利用这些图像为每个肺选择并放置模板。然后生成一张均衡后的X线片。在两名男性志愿者（均为33岁）和一个体模中采集X线片。
在传统体模X线片上，肺区和非肺区的光密度分别为2.07和0.55；均衡后，相应的光密度为2.06和1.42。在肺外，X线摄影对比度（光密度差异）增加了两倍；在肺内，由于射线硬化，X线摄影对比度有非常小的下降。使用20毫秒的曝光时间获得了均衡良好且相对无伪影的X线片。
在实验室中证明FWE系统是可行的。
