Whole gamma imaging: a new concept of PET combined with Compton imaging
Whole gamma imaging: a new concept of PET combined with Compton imaging
复制标题
全伽玛成像：PET结合康普顿成像的新概念
DOI：
10.1088/1361-6560/ab8e89
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Taiga Yamaya
中科院分区：
文献类型：
--
作者：
Eiji Yoshida;Hideaki Tashima;Kotaro Nagatsu;Atsushi Tsuji;Kei Kamada;Katia Parodi;Taiga Yamaya
我们提出了全伽马成像（WGI）的概念，利用所有可探测的伽马射线进行成像。在PET环的视场中插入一个额外的探测器环，用作散射器，这样康普顿成像方法就可以检测到单个伽马射线。特别是，对于几乎同时发射额外伽马射线的非纯正电子发射体，将启用三重伽马成像；通过使用附加伽马射线的康普顿锥，可以对每个响应线（LOR）进行定位。我们开发了一个原型来展示WGI概念的证明。散射环直径为20 cm， PET环直径为66 cm。对于来自137 Cs点源的662 kev伽马射线的康普顿成像，通过列表模式OSEM算法获得的空间分辨率在离中心8cm位置为4.4 mm FWHM，在中心位置为13.1 mm FWHM。对于22 Na点源的PET成像，所有位置的空间分辨率约为2 mm FWHM。对于三倍伽马成像，仅通过绘制1275 kev伽马射线的每个LOR和每个康普顿锥之间的交点，就获得了22 Na点源的5.7 mm（中心）和4.8 mm（离中心8 cm）的FWHM。没有应用图像重建。作为非纯正电子发射体的实际候选材料，钪-44以同样的方法获得了6.6 mm的FWHM（中心）和5.8 mm的FWHM（离中心8 cm）。这种既不需要耗时的事件整合也不需要迭代图像重建的直接成像方法可以允许对微量活动进行体内实时跟踪。我们的初步结果显示了WGI概念的可行性，这是PET和康普顿成像的一种新组合。
We proposed a concept of whole gamma imaging (WGI) that utilizes all detectable gamma rays for imaging. An additional detector ring, which is used as the scatterer, is inserted in the field-of-view of a PET ring so that single gamma rays can be detected by the Compton imaging method. In particular, for the non-pure positron emitters which emit an additional gamma ray almost at the same time, triple gamma imaging will be enabled; localization on each line-of-response (LOR) is possible by using the Compton cone of the additional gamma ray. We developed a prototype to show a proof of the WGI concept. The diameters of scatterer ring and PET ring were set as 20 cm and 66 cm, respectively. For Compton imaging of the 662-keV gamma ray from a 137 Cs point source, spatial resolution obtained by the list-mode OSEM algorithm was 4.4 mm FWHM at the 8 cm off-center position and 13.1 mm FWHM at the center position. For PET imaging of a 22 Na point source, spatial resolution was about 2 mm FWHM at all positions. For the triple gamma imaging, 5.7 mm FWHM (center) and 4.8 mm FWHM (8 cm off-center) were obtained for the 22 Na point source just by plotting the intersecting points between each LOR and each Compton cone of the 1275-keV gamma ray. No image reconstruction was applied. Scandium-44 was produced as a practical candidate of the non-pure positron emitters, and 6.6 mm FWHM (center) and 5.8 mm FWHM (8 cm off-center) were obtained in the same manner. This direct imaging approach which neither requires time-consuming event integration nor iterative image reconstruction may allow in vivo real-time tracking of a tiny amount of activity. Our initial results showed the feasibility of the WGI concept, which is a novel combination of PET and Compton imaging.