Compartmental analysis of washout effect in rat brain: in-beam OpenPET measurement using a 11C beam
Compartmental analysis of washout effect in rat brain: in-beam OpenPET measurement using a 11C beam
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DOI：
10.1088/0031-9155/58/23/8281
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发表时间：
2013-12
影响因子：
3.5
通讯作者：
Y. Hirano;S. Kinouchi;Y. Ikoma;E. Yoshida;H. Wakizaka;Hiroshi Ito;T. Yamaya
中科院分区：
文献类型：
--
作者：
Y. Hirano;S. Kinouchi;Y. Ikoma;E. Yoshida;H. Wakizaka;Hiroshi Ito;T. Yamaya
预期束内正电子发射断层扫描（PET）能够使用正电子发射体（β+衰变）实现剂量验证的可视化。为了准确地进行剂量验证，应对正电子发射体的冲刷进行校正。此外，定量洗脱率作为诊断指标具有潜在的有用性，但尚未研究其建模。因此，在本文中，我们应用隔室分析，在束PET数据采集我们的小型OpenPET原型，它有一个物理开放的视野（FOV）之间的两个探测器环。将大鼠大脑定位在FOV处，并通过11 C束照射。在照射后即刻测量照射野的时间活度曲线，并基于两个模型获得洗脱率：二洗脱模型（中等衰变，k2 m;慢衰变，k2 s）在兔子辐照研究中开发;以及核医学中使用的二室模型，其中从组织到血液的流出（k2），评价组织中从第一隔室到第二隔室的流入（k3）和流出（k4）。观察到的k2 m和k2 s分别为0.34和0.005 min-1，这与兔子研究一致。此外，k2 m与使用15 O-水的动态PET测量的脑血流量（CBF）的洗脱率接近，而k2、k3和k4分别为0.16、0.15和0.007 min-1。我们目前的工作表明，11 C的动力学可能与CBF或含有11 C原子的分子的渗透性可能受到转运蛋白的调节，因为与简单的扩散示踪剂相比，k2相对较低。
In-beam positron emission tomography (PET) is expected to enable visualization of a dose verification using positron emitters (β+ decay). For accurate dose verification, correction of the washout of the positron emitters should be made. In addition, the quantitative washout rate has a potential usefulness as a diagnostic index, but modeling for this has not been studied yet. In this paper, therefore, we applied compartment analyses to in-beam PET data acquired by our small OpenPET prototype, which has a physically opened field-of-view (FOV) between two detector rings. A rat brain was located at the FOV and was irradiated by a 11C beam. Time activity curves of the irradiated field were measured immediately after the irradiations, and the washout rate was obtained based on two models: the two-washout model (medium decay, k2m; slow decay, k2s) developed in a study of rabbit irradiation; and the two-compartment model used in nuclear medicine, where efflux from tissue to blood (k2), influx (k3) and efflux (k4) from the first to second compartments in tissue were evaluated. The observed k2m and k2s were 0.34 and 0.005 min−1, respectively, which was consistent with the rabbit study. Also k2m was close to the washout rate in cerebral blood flow (CBF) measurements by dynamic PET with 15O-water, while, k2, k3, and k4 were 0.16, 0.15 and 0.007 min−1. Our present work suggested the dynamics of 11C might be relevant to CBF or permeability of a molecule containing 11C atoms might be regulated by a transporter because the k2 was relatively low compared with a simple diffusion tracer.