While the pursuit of better time resolution in positron emission tomography (PET) is rapidly evolving, little work has been performed on time of flight (TOF) image quality at high time resolution in the presence of modelling inconsistencies. This works focuses on the effect of using the wrong attenuation map in the system model, causing perturbations in the reconstructed radioactivity image. Previous work has usually considered the effects to be local to the area where there is attenuation mismatch, and has shown that the quantification errors in this area tend to reduce with improved time resolution. This publication shows however that errors in the PET image at a distance from the mismatch increase with time resolution. The errors depend on the reconstruction algorithm used. We quantify the errors in the hypothetical case of perfect time resolution for maximum likelihood reconstructions. In addition, we perform reconstructions on simulated and patient data. In particular, for respiratory-gated reconstructions from a wrong attenuation map, increased errors are observed with improved time resolutions in areas close to the lungs (e.g. from 13.3% in non-TOF to up to 20.9% at 200 ps in the left ventricle).

中文翻译：

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衰减不匹配对飞行时间PET重建的影响。

尽管在正电子发射断层扫描（PET）中寻求更好的时间分辨率的方法正在迅速发展，但是在存在建模不一致的情况下，在高时间分辨率下对飞行时间（TOF）图像质量所做的工作很少。这项工作着眼于在系统模型中使用错误的衰减图的效果，从而在重建的放射性图像中引起干扰。先前的工作通常认为影响仅存在于衰减失配的区域，并且表明该区域的量化误差会随着时间分辨率的提高而降低。然而，该出版物显示，距失配一定距离的PET图像中的误差随时间分辨率而增加。误差取决于所使用的重建算法。我们在最大时间似然重建的理想时间分辨率假设情况下量化误差。此外，我们对模拟和患者数据进行重建。尤其是，对于从错误的衰减图进行的呼吸门重建，在靠近肺部的区域中，随着时间分辨率的提高，观察到的误差增加（例如，从非TOF的13.3％上升到左心室200 ps的20.9％） 。