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Microworks 微結構及X射線光柵

European Radiology Experimental -人體尸體的全身X光暗場攝影-X射線光柵

2022-06-16 14:13:10 unistar
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人體尸體的全身X光暗場攝影 


背景:基于光柵的 X 射線暗場和相襯成像允許提取關于折射和小角度散射的信息,超出常規(guī)衰減成像的能力。最近實現(xiàn)了臨床轉化的一小步,允許對人類進行進一步研究。

方法:在倫理委員會批準后,我們以前后方向掃描了人類尸體的全身。六個測量值拼接在一起形成全身圖像。所有射線照片均在三光柵、大物體、X射線暗場掃描儀上拍攝,每次持續(xù)約40秒。評估了不同解剖區(qū)域的信號強度。使用不同的體模材料分析了由光束硬化而不是小角度散射引起的能見度降低的幅度。腹部的最大有效劑量為0.3 mSv。

結果:在整個人體中結合吸收和暗場射線照相在技術上是可能的。在幾個骨結構、異物和肺中發(fā)現(xiàn)了高信號水平。肺的信號水平為 0.25 ± 0.13(平均值 ± 標準偏差),骨骼為 0.08 ± 0.06,軟組織為 0.023 ± 0.019,抗生素珠鏈為 0.30 ± 0.02。我們發(fā)現(xiàn)不會產生小角度散射的模體材料可以產生強烈的能見度降低信號。

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.

文章鏈接: Andrejewski, Jana, et al. "Whole-body x-ray dark-field radiography of a human cadaver." European Radiology Experimental 5.1 (2021): 1-9.


文章中所使用的光柵是由德國Microworks生產定制、生產的(點擊了解詳情)。具體參數如下:


源光柵 (G0) 的面積為 5.0 ×2.5 cm2,周期為 68.72 μm,占空比為 0.7;

其他兩個光柵(G1:周期 8.73 μm,占空比0.5,G2:周期 10 μm,占空比 0.5)由八塊拼接而成,每塊尺寸為 5.0 × 2.5 cm2,以實現(xiàn)每個光柵的總尺寸為 40 × 2.5 cm2。 G0-G1 和G1-G2 距離分別為 1.60 和 0.25 m。 全部光柵是金填充衰減光柵(金填充150–200 μm 的高度)。



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