Computed tomography has greatly improved over the last decade, especially through x-ray dose exposure reduction while maintaining image quality. Herein, a new concept is proposed to improve the contrast-to-noise ratio (CNR) by including the time-of-flight (TOF) information of individual photons to obtain further insight on the photon's trajectory and to reject scatter contribution. The proof of the concept relies on both simulation and experimental measurements in a cone-beam computed tomography arrangement. Results show a statistical difference between the TOF of scattered and primary photons exploitable in TOF computed tomography. For a large volume of the size of a human abdomen, a scatter reduction from 296% to 4% is achieved in our simulation setup with perfect timing measurements which yields a 110% better CNR, or a dose reduction by a factor of four. Cup artifacts are also reduced from 24.7% to 0.8%, and attenuation inaccuracies are improved from -26.3% to -0.8%. With 100 ps and 10 ps FWHM timing jitters, respectively 75% and 95% of the scatter contribution can be removed with marginal gains below 10 ps. Experimental measurements confirm the feasibility of measuring statistical differences between the TOF of scattered and primary photons.

中文翻译：

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飞行时间计算机断层扫描-原理证明。

在过去的十年中，计算机断层扫描技术得到了极大的改善，特别是通过在保持图像质量的同时减少了X射线剂量。在此，提出了一种新的概念，以通过包括单个光子的飞行时间（TOF）信息来提高对比度噪声比（CNR），以获得对光子轨迹的进一步了解并拒绝散射贡献。该概念的证明依赖于锥形束计算机断层扫描装置中的仿真和实验测量。结果表明，在TOF计算机断层扫描中可利用的散射光子和原始光子的TOF之间存在统计差异。对于大体积的人腹部，在我们的模拟设置中，通过完美的定时测量可以将散射从296％降低到4％，从而使CNR改善110％，或剂量减少四倍。杯子伪影也从24.7％减少到0.8％，衰减误差从-26.3％改善到-0.8％。利用100 ps和10 ps的FWHM时序抖动，可以在10 ps以下的边际增益下分别消除75％和95％的散射贡献。实验测量结果证实了测量散射光子和原始光子的TOF之间的统计差异的可行性。