沙特阿卜杜拉国王科技大学Omar F. Mohammed 最新Matter：通过ΔE-E望远镜结构闪烁体实现的多能量X射线成像

X射线成像技术在科学研究、安全检查、工业环境中的质量控制和先进医疗诊断等各个实际领域中发挥着关键作用。传统的单能量X射线成像技术在医学成像和安全检查中难以精确区分物质。双能量X射线成像技术部分弥补了这一局限性，但它在识别独特的光谱信息和X射线成像物体的细节方面仍然具有挑战。除此以外，双能x射线成像技术还存在着诸多问题，例如复杂且昂贵的组件（如两个传感器之间的对准和连接）、过量辐射剂量的风险以及底层信噪比的降低。

鉴于此，沙特阿卜杜拉国王科技大学Omar F. Mohammed教授带领研究团队系统地设计和制造了一种具有ΔE-E望远镜结构的六层闪烁体来实现能量鉴别和物质识别功能。通过三层不同的闪烁体，具有不同能量仓的x射线被依次转换为三色通道。三个插入的过滤层不仅能硬化x射线能谱，还能保证望远镜闪烁体的发光范围覆盖整个可见光谱且互相不重叠，这使得可以根据对应的发射颜色直接区别具有不同CT值的物质。此外，ΔE-E望远镜闪烁体空间分辨率在不同X射线电压下均超过了22 lp/mm。在行李检查的概念实验中，复杂物体得到了成功的区分且并没有遗漏任何细节。这项工作有潜力显著改进安全检查和医学诊断领域中的X射线成像技术。

Figure 1. Schematic illustration of the three X-ray imaging technologies (A) SEXIT includes one scintillator layer and one image sensor (grayscale) with the characteristic of energy integration. (B) DEXIT includes two scintillator layers, two image sensors (grayscale), and one metal energy filter with the characteristics of energy integration and energy separation. (C) MEXIT includes three scintillator layers, two optical/energy filters, one energy filter, and one color image sensor with the characteristics of energy integration, energy separation, and the acquisition of spectral information. Trichromatic vision (red, green, blue) realized by three scintillator layers (ΔE1 layer, ΔE2 layer, E layer) individually. Filter 1 (600 nm longpass) and filter 2 (500 nm longpass) blocked the extra photons to avoid spectral overlap and hardened the X-ray beam with filter 3 (CaF2) synergistically.

Figure 2. X-ray-induced emissions of the telescope scintillator under different X-ray tube voltages (A) X-ray energy deposition distribution in each layer of the telescope scintillator. (B) X-ray tube voltage-dependent (13–70 kV) RL spectra of the telescope scintillator. (C) X-ray tube voltage-dependent (13–70 kV) RL mapping mode of the telescope scintillator. (D) Change trend of the coordinated CIE derived from the corresponding RL spectra. (E) X-ray images of the telescope scintillator across the X-ray tube voltage from 13 to 70 kV. (F) RL spectra and X-ray-induced emissions of each scintillator layer and two conventional scintillators of BGO and CdWO4. The insets show their photographs under X-ray excitation.

Figure 3. Material-specific capability of multi-energy X-ray imaging (A) X-ray energy-dependent CT number curves of eight substances (I–VIII). (B) Histograms of the CT numbers of each substance under low-, medium-, and high-energy sections. (C) Color-reconstructed multi-energy X-ray image of I–VIII. (D and E) Corresponding RL spectra (D) and the CIE coordinates (E) of I–VIII. (F–H) X-ray images of I–VIII under low-, medium-, and high-X-ray energy, respectively

Figure 4. Conceptual multi-energy X-ray imaging for baggage inspection (A) Illustration of the multi-energy X-ray imaging technology for baggage inspection. (B) Sketch of the simulated baggage with eight various objects (objects a–h). (C and D) Original (C) and color-reconstructed (D) multi-energy X-ray images of the simulated baggage. (E–G) Three ROIs with different emission wavelength ranges of the original multi-energy X-ray image of the simulated baggage. (H) Modulated transfer function curves of the telescope scintillator under low-, medium-, and high-X-ray tube voltages. (I–K) X-ray images of the standard line pair card (type 39b) taken by telescope scintillator under (I) low, (J) medium, and (K) high kilovolts, respectively.

He et al., Multi-energy X-ray imaging enabled by ΔE-E telescope scintillator, Matter (2024), https://doi.org/10.1016/j.matt.2024.05.029

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