Geometrical properties of a digital beam attenuator system.
Geometrical properties of a digital beam attenuator system.
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数字光束衰减器系统的几何特性。
DOI：
10.1118/1.596086
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发表时间：
1987
期刊：
影响因子：
3.8
通讯作者：
Mistretta,CA
中科院分区：
文献类型：
--
作者：
Hasegawa,BH;Dobbins3rd,JT;Naimuddin,S;Peppler,WW;Mistretta,CA
开发了一种数字射束衰减器系统，用于自动生成胸部X线摄影的患者特定补偿滤波器。初始低剂量测试图像用于生成衰减器，该衰减器通过将多层重金属材料叠印到非衰减基板上来制造。随后将衰减器插入到X射线束中，以进行最终的补偿射线照片。焦斑模糊和有限衰减器分辨率的影响导致最终补偿图像仅包含高空间频率信息。该过程的频率响应不能通过调制传递函数严格描述，但是对于低对比度条件，可以获得补偿图像中剩余频率的近似值。结果表明，在原始64×64的测试图像上，衰减器需要一个4×4的模糊函数才能给出合适的补偿图像外观。一种建议的衰减器印刷方案以16×16矩阵印刷衰减器，交错连续印刷层以实现所需的64×64采样和适当的模糊。所得到的补偿图像具有良好的解剖清晰度，并包含一个频率响应类似的补偿技术正在调查的Plewes和Sorenson。
A digital beam attenuator system has been developed to automatically generate patient‐specific compensating filters for chest radiography. An initial low‐dose test image is used to generate the attenuator, which is fabricated by overprinting multiple layers of a heavy‐metal material onto a nonattenuating substrate. The attenuator is subsequently inserted into the x‐ray beam for a final compensated radiograph. The effects of focal spot blurring and limited attenuator resolution result in the final compensated image containing only high‐spatial frequency information. The frequency response of the process is not strictly describable by a modulation transfer function, but an approximation of the frequencies remaining in the compensated image is obtained for low‐contrast conditions. It is found that a 4×4 blurring function on the original 64×64 test image is required for the attenuator to give appropriate compensated image appearance. A proposed attenuator printing scheme prints the attenuator in a 16×16 matrix, staggering successively printed layers to achieve the required 64×64 sampling with appropriate blurring. The resulting compensated image has good anatomical definition and contains a frequency response similar to that obtained by compensation techniques being investigated by Plewes and Sorenson.