Institute of Nuclear Medicine, UCL and UCLH NHS Foundation Trust, London, UK.
Phys Med Biol. 2011 Jul 21;56(14):R85-112. doi: 10.1088/0031-9155/56/14/R01. Epub 2011 Jun 23.
Detection of scattered gamma quanta degrades image contrast and quantitative accuracy of single-photon emission computed tomography (SPECT) imaging. This paper reviews methods to characterize and model scatter in SPECT and correct for its image degrading effects, both for clinical and small animal SPECT. Traditionally scatter correction methods were limited in accuracy, noise properties and/or generality and were not very widely applied. For small animal SPECT, these approximate methods of correction are often sufficient since the fraction of detected scattered photons is small. This contrasts with patient imaging where better accuracy can lead to significant improvement of image quality. As a result, over the last two decades, several new and improved scatter correction methods have been developed, although often at the cost of increased complexity and computation time. In concert with (i) the increasing number of energy windows on modern SPECT systems and (ii) excellent attenuation maps provided in SPECT/CT, some of these methods give new opportunities to remove degrading effects of scatter in both standard and complex situations and therefore are a gateway to highly quantitative single- and multi-tracer molecular imaging with improved noise properties. Widespread implementation of such scatter correction methods, however, still requires significant effort.
散射伽马量子的探测会降低单光子发射计算机断层扫描（SPECT）成像的图像对比度和定量准确性。本文综述了用于描述和建模 SPECT 中的散射并校正其图像降级效应的方法，既适用于临床 SPECT 也适用于小动物 SPECT。传统的散射校正方法在准确性、噪声特性和/或通用性方面存在局限性，并且应用并不广泛。对于小动物 SPECT，由于检测到的散射光子的分数较小，这些近似的校正方法通常就足够了。这与患者成像形成对比，在患者成像中，更高的准确性可以显著提高图像质量。因此，在过去二十年中，已经开发了几种新的和改进的散射校正方法，尽管通常是以增加复杂性和计算时间为代价。随着（i）现代 SPECT 系统上的能量窗口数量的增加，以及（ii）SPECT/CT 中提供的出色衰减图，其中一些方法为在标准和复杂情况下消除散射的降级效应提供了新的机会，因此是实现具有改善噪声特性的高定量单探针和多探针分子成像的途径。然而，广泛实施这些散射校正方法仍需要付出巨大的努力。
