SPATIAL DISTRIBUTION OF PULMONARY FUNCTION OF THE RAT LUNG

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。众所周知，辐射引起的大鼠肺功能丧失的程度取决于受辐射的区域。然而，人们对这些地区差异的根本原因知之甚少。一种假设是，这种效应可能是由于辐射前肺功能的不均匀分布造成的。为了确定局部功能的区域差异可以在多大程度上解释辐射导致的功能损失的区域差异，我们希望通过测量以下参数的空间分布来测量肺功能的分布：1)通气量：这将通过成像气相中的超极化氙气来测量。2)表面积体积比：组织中溶解的氙气与气相中的氙气的磁共振频率不同。通过测量去极化射频脉冲作用后短时间内溶解的超极化氙气的197ppm信号，得到与有效气体交换面积成正比的信号。3)红细胞的气体摄取：当氙气被红细胞摄取时，其磁共振频率发生第二次漂移至211ppm。因此，红血球的气体摄取可以通过在这个频率上的成像来具体测量。这项测量提供了毛细血管血容量与血-气屏障健康状况的区域分布。4)全肺动态频谱显示197和211ppm共振已恢复。5)质子磁共振胸腔容量估算：要计算平均胸腔容量，需要质子图像显示解剖结构。从辐射实验中使用的所有区域的这些图像中，将获得预处理值，并将其与可用的治疗后功能损失数据相关联。6)可选-使用Gd注射进行厚厚肺片的MR灌注我们打算按照概述的方案扫描3-6只大鼠。确切的数字将取决于结果的可变性。议定书的第1-5部分与Driehuys PNAS提交的文件中执行的内容相同。如果项目6对CIVM的学生和教职员工有好处，将被列为研究的一个可选部分。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The magnitude of radiation-induced function loss in the rat lung is known to be dependent on which region is irradiated. However, the underlying cause of these regional differences is poorly understood. One hypothesis is that the effect may result from a non-uniform distribution of function over the lung, prior to irradiation. To determine the extent to which regional variations in local function can explain regional variations in radiation-induced function loss, we want to measure the distribution of function over the lung by measuring the spatial distribution of the following parameters: 1) Ventilation: This will be measured by imaging hyperpolarized Xenon gas in gas phase. 2) Surface-to-volume ratio: The MR frequency of Xenon dissolved in tissue differs from Xenon in gas phase. By measuring the 197ppm signal of dissolved hyperpolarized Xenon for short period after applying a depolarizing rf-pulse, we want to obtain signals proportional to the available gas-exchange surface. 3) Gas uptake in red blood cells: When Xenon is taken up in red blood cells, its MR frequency undergoes a second shift to 211ppm. Thus gas uptake by red blood cells can be measured specifically by imaging on this frequency. This measurement provides a regional distribution of capillary blood volume coupled with blood-gas barrier health. 4) Whole-lung dynamic spectroscopy showing recovery of the 197 and 211 ppm resonances. 5) Proton MRI for chest volume estimation: To allow the calculation of volume averages, proton images revealing the anatomy are needed. From these images for all regions used in the irradiation experiments, pre-treatment values will be obtained and correlated the available post-treatment function loss data. 6) Optional - MR perfusion of a thick slab of lung using Gd injection We intend to scan 3-6 rats according to the outlined protocol. Exact numbers will depend on the variability in the results. Parts 1-5 of the protocol are identical to those carried out in the Driehuys PNAS submission. Item 6 would be included as an optional component to the study if there is benefit to CIVM students and faculty.