European Radiology Experimental -人体尸体的全身X光暗场摄影-X射线光栅
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人体尸体的全身X光暗场摄影
背景：基于光栅的 X 射线暗场和相衬成像允许提取关于折射和小角度散射的信息，超出常规衰减成像的能力。最近实现了临床转化的一小步，允许对人类进行进一步研究。
方法：在伦理委员会批准后，我们以前后方向扫描了人类尸体的全身。六个测量值拼接在一起形成全身图像。所有射线照片均在三光栅、大物体、X射线暗场扫描仪上拍摄，每次持续约40秒。评估了不同解剖区域的信号强度。使用不同的体模材料分析了由光束硬化而不是小角度散射引起的能见度降低的幅度。腹部的最大有效剂量为0.3 mSv。
结果：在整个人体中结合吸收和暗场射线照相在技术上是可能的。在几个骨结构、异物和肺中发现了高信号水平。肺的信号水平为 0.25 ± 0.13（平均值 ± 标准偏差），骨骼为 0.08 ± 0.06，软组织为 0.023 ± 0.019，抗生素珠链为 0.30 ± 0.02。我们发现不会产生小角度散射的模体材料可以产生强烈的能见度降低信号。
Whole-body x-ray dark-field radiography of a human cadaver
Abstract
Background: Grating-based x-ray dark-field and phase-contrast imaging allow extracting information about refraction and small-angle scatter, beyond conventional attenuation. A step towards clinical translation has recently been achieved, allowing further investigation on humans.
Methods: After the ethics committee approval, we scanned the full body of a human cadaver in anterior-posterior orientation. Six measurements were stitched together to form the whole-body image. All radiographs were taken at a three-grating large-object x-ray dark-field scanner, each lasting about 40 s. Signal intensities of different anatomical regions were assessed. The magnitude of visibility reduction caused by beam hardening instead of small-angle scatter was analysed using different phantom materials. Maximal effective dose was 0.3 mSv for the abdomen.
Results: Combined attenuation and dark-field radiography are technically possible throughout a whole human body. High signal levels were found in several bony structures, foreign materials, and the lung. Signal levels were 0.25 ± 0.13 (mean ± standard deviation) for the lungs, 0.08 ± 0.06 for the bones, 0.023 ± 0.019 for soft tissue, and 0.30 ± 0.02 for an antibiotic bead chain. We found that phantom materials, which do not produce small-angle scatter, can generate a strong visibility reduction signal.
Conclusion: We acquired a whole-body x-ray dark-field radiograph of a human body in few minutes with an effective dose in a clinical acceptable range. Our findings suggest that the observed visibility reduction in the bone and metal is dominated by beam hardening and that the true dark-field signal in the lung is therefore much higher than that of the bone.
Keywords: Dark-field imaging; Human body; Radiography; Whole-body imaging; X-rays.
文章中所使用的光栅是由德国Microworks生产定制、生产的（点击了解详情）。具体参数如下：
源光栅 (G0) 的面积为 5.0 ×2.5 cm2，周期为 68.72 μm，占空比为 0.7；
其他两个光栅（G1：周期 8.73 μm，占空比0.5，G2：周期 10 μm，占空比 0.5）由八块拼接而成，每块尺寸为 5.0 × 2.5 cm2，以实现每个光栅的总尺寸为 40 × 2.5 cm2。 G0-G1 和G1-G2 距离分别为 1.60 和 0.25 m。 全部光栅是金填充衰减光栅（金填充150–200 μm 的高度）。