Despite its success in many biomedical applications, Positron Emission Tomography (PET) has the drawback of typically having lower spatial resolution and higher noise respect to other medical imaging techniques. The best achievable spatial resolution in PET scanners is limited by factors such as the positron range, non-collinearity and the size of the detector crystals. In this work, we present a novel method that uses series of image reconstructions (super-iterations) to go beyond the expected resolution-noise limits for a given PET acquisition. The image quality improvement is achieved using the projections of the previous image reconstruction to redistribute the measured counts of each line-of-response (LOR) into several subLORs, from which a new activity distribution with better quality is reconstructed. The method was evaluated with data from the preclinical scanner 4R-SuperArgus PET/CT, using the NEMA NU4-2008 image quality phantom, a cold Derenzo phantom, and an in-vivo FDG cardiac study on a rat. Resolution and recovery coefficient (RC) improvement of ∼10% was achieved while keeping the same noise level. Qualitative results from the in-vivo study also confirm this improvement in image quality. The proposed method is able to achieve significantly better images at the expense of a modest increase of the computational time, and it could be also applied to other modalities, such as SPECT and Compton Cameras.

中文翻译：

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PET中的超级迭代图像重建

尽管在许多生物医学应用中取得了成功，但正电子发射断层扫描（PET）的缺点是相对于其他医学成像技术通常具有较低的空间分辨率和较高的噪声。PET扫描仪中可获得的最佳空间分辨率受到诸如正电子范围，非共线性和检测器晶体尺寸等因素的限制。在这项工作中，我们提出了一种新颖的方法，该方法使用一系列图像重建（超迭代）来超出给定PET采集的预期分辨率噪声极限。使用先前图像重建的投影将每个响应线（LOR）的测量计数重新分配到几个subLOR中，可以实现图像质量的改善，从中重建质量更高的新活动分布。使用临床前扫描仪4R-SuperArgus PET / CT的数据，使用NEMA NU4-2008图像质量体模，冷Derenzo体模和对大鼠的体内FDG心脏研究，对该方法进行了评估。在保持相同噪声水平的同时，分辨率和恢复系数（RC）提升了约10％。体内研究的定性结果也证实了图像质量的改善。所提出的方法能够以适度增加计算时间为代价获得明显更好的图像，并且还可以应用于其他形式，例如SPECT和Compton相机。在保持相同噪声水平的同时，分辨率和恢复系数（RC）提升了约10％。体内研究的定性结果也证实了图像质量的改善。所提出的方法能够以适度增加计算时间为代价获得明显更好的图像，并且还可以应用于其他形式，例如SPECT和Compton相机。在保持相同噪声水平的同时，分辨率和恢复系数（RC）提升了约10％。体内研究的定性结果也证实了图像质量的改善。所提出的方法能够以适度增加计算时间为代价获得明显更好的图像，并且还可以应用于其他形式，例如SPECT和Compton相机。