论文标题

X射线光子计数数据校正通过深度学习

X-ray Photon-Counting Data Correction through Deep Learning

论文作者

Li, Mengzhou, Rundle, David S., Wang, Ge

论文摘要

X射线光子计数检测器(PCD)近年来由于其低噪声和能量辨别能力而引起了人们的关注。与PCD相关的能量/光谱维度可能带来巨大的好处,例如材料分解,束硬化和金属伪像的减少以及低剂量CT成像。但是,X射线PCD目前受到几个技术问题的限制,尤其是电荷分裂(包括电荷共享和K-shell荧光再吸收或逃脱)和脉搏堆积效应,这些效应扭曲了能量谱并损害了数据质量。通过硬件改进和分析建模对RAW PCD测量进行纠正相当昂贵且复杂。因此,在这里,我们提出了一种基于神经网络的深度PCD数据校正方法,该方法将不完美的数据直接映射到监督学习模式下的理想数据。在这项工作中,我们首先建立一个完整的模拟模型,其中包含电荷分裂和脉搏堆积效果。然后,将模拟的PCD数据和地面真相对应物馈送到专门设计的深层对抗网络,以进行PCD数据校正。接下来,训练有素的网络用于校正单独生成的PCD数据。测试结果表明,训练有素的网络成功地从$ \ pm6 \%$相对误差范围内的扭曲测量中恢复了理想频谱。在投影和重建域中清楚地观察到了重要的数据和图像保真度改善。

X-ray photon-counting detectors (PCDs) are drawing an increasing attention in recent years due to their low noise and energy discrimination capabilities. The energy/spectral dimension associated with PCDs potentially brings great benefits such as for material decomposition, beam hardening and metal artifact reduction, as well as low-dose CT imaging. However, X-ray PCDs are currently limited by several technical issues, particularly charge splitting (including charge sharing and K-shell fluorescence re-absorption or escaping) and pulse pile-up effects which distort the energy spectrum and compromise the data quality. Correction of raw PCD measurements with hardware improvement and analytic modeling is rather expensive and complicated. Hence, here we proposed a deep neural network based PCD data correction approach which directly maps imperfect data to the ideal data in the supervised learning mode. In this work, we first establish a complete simulation model incorporating the charge splitting and pulse pile-up effects. The simulated PCD data and the ground truth counterparts are then fed to a specially designed deep adversarial network for PCD data correction. Next, the trained network is used to correct separately generated PCD data. The test results demonstrate that the trained network successfully recovers the ideal spectrum from the distorted measurement within $\pm6\%$ relative error. Significant data and image fidelity improvements are clearly observed in both projection and reconstruction domains.

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