3D Compton image reconstruction method for whole gamma imaging
3D Compton image reconstruction method for whole gamma imaging
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DOI：
10.1088/1361-6560/abb92e
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发表时间：
2020-11-21
影响因子：
3.5
通讯作者：
Yamaya, Taiga
中科院分区：
文献类型：
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作者：
Tashima, Hideaki;Yoshida, Eiji;Yamaya, Taiga
康普顿成像或康普顿照相机成像已得到很好的研究，但其在核医学和分子成像方面的优势尚未得到证实。因此，这项工作的目的是比较康普顿成像与正电子发射断层扫描（PET）通过使用相同的成像平台的全伽马成像（WGI）。WGI是通过将散射体环插入到PET环中来将PET与康普顿成像相结合的概念。该概念利用不同类型的伽马射线进行3D断层成像。在本文中，我们改造了我们以前的WGI原型的小动物成像，我们开发了一种图像重建方法的基础上的列表模式有序子集期望最大化算法，结合探测器响应函数建模，随机校正和归一化（灵敏度校正）的PET和康普顿成像。据我们所知，这是世界上第一个实现全环康普顿成像系统。我们选择Zr-89作为成像目标，因为Zr-89核素发射909 keV的单伽马射线以及正电子，并且我们可以直接将909 keV光子的康普顿成像与PET（一种成熟的模式）进行比较。我们测量了一个圆柱体模和一个小杆体模填充Zr-89解决方案的10.3 MBq和10.2 MBq的活动，分别为1小时。在PET和Compton成像中均采用归一化重建圆柱体模的均匀放射性分布。Compton成像和PET的感兴趣区域值的变异系数分别为4.2%和3.3%;差异可能由检测到的计数值的差异来解释。小杆体模实验表明，WGI康普顿成像的空间分辨率优于3.0毫米的周边区域，但中心区域的分辨率较低。PET清晰地分辨出任何位置的2.2 mm棒。我们测量了小鼠注射9.8MBq Zr-89草酸盐后1小时，1天。在小鼠骨结构中吸收的Zr-89被清楚地描绘，并且康普顿成像结果与PET图像一致，特别是对于散射体环内的区域。总之，我们证明了性能的WGI使用发达的康普顿图像重建方法。我们实现了质量接近PET的康普顿成像，这支持了康普顿成像优于PET的未来预期。
Compton imaging or Compton camera imaging has been studied well, but its advantages in nuclear medicine and molecular imaging have not been demonstrated yet. Therefore, the aim of this work was to compare Compton imaging with positron emission tomography (PET) by using the same imaging platform of whole gamma imaging (WGI). WGI is a concept that combines PET with Compton imaging by inserting a scatterer ring into a PET ring. This concept utilizes diverse types of gamma rays for 3D tomographic imaging. In this paper, we remodeled our previous WGI prototype for small animal imaging, and we developed an image reconstruction method based on a list-mode ordered subset expectation maximization algorithm incorporating detector response function modeling, random correction and normalization (sensitivity correction) for either PET and Compton imaging. To the best of our knowledge, this is the world's first realization of a full-ring Compton imaging system. We selected Zr-89 as an imaging target because a Zr-89 nuclide emits a 909 keV single-gamma ray as well as a positron, and we can directly compare Compton imaging of 909 keV photons with PET, a well-established modality. We measured a cylindrical phantom and a small rod phantom filled with Zr-89 solutions of 10.3 MBq and 10.2 MBq activity, respectively, for 1 h each. The uniform radioactivity distribution of the cylindrical phantom was reconstructed with normalization in both PET and Compton imaging. Coefficients of variation for region-of-interest values were 4.2% for Compton imaging and 3.3% for PET; the difference might be explained by the difference in the detected count number. The small rod phantom experiment showed that the WGI Compton imaging had spatial resolution better than 3.0 mm at the peripheral region although the center region had lower resolution. PET resolved 2.2 mm rods clearly at any location. We measured a mouse for 1 h, 1 d after injection of 9.8 MBq Zr-89 oxalate. The Zr-89 assimilated in the mouse bony structures was clearly depicted, and Compton imaging results agreed well with PET images, especially for the region inside the scatterer ring. In conclusion, we demonstrated the performance of WGI using the developed Compton image reconstruction method. We realized Compton imaging with a quality approaching that of PET, which is supporting a future expectation that Compton imaging outperforms PET.