IN VIVO DETECTION OF RADIATION-INDUCED TISSUE DAMAGE IN KIDNEY BY C13 MRSI

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 最近将核超极化技术引入液态，使核磁共振波谱成像(MRSI)能够在体内检测C-13标记的内源性代谢物。我们研究了在中等剂量下使用这种新技术评估放射损伤的可行性，这可能导致放射治疗。我们选择肾脏组织是因为肾脏是一个对辐射敏感的器官，并提供内部控制。在本研究中，我们使用体重200-450g的Wistar雄性大鼠，采用平行X射线单侧照射一侧肾脏的方法制作模型。最初，大鼠接受15Gy射线照射，并在照射后第21天接受C-13磁共振波谱成像(MRSI)。在MRSI中，大鼠静脉注射80 mM[113C]丙酮酸超极化溶液。在HyperSenseTM偏振器(牛津仪器)上使用DNP技术进行超极化。快速化学位移成像(CSI)在3T下每隔6秒采集两个肾脏的轴位切片，测量代谢产物丙酮酸、乳酸和丙氨酸的动态和空间分布。动物在成像后被处死，采集肾脏组织进行组织病理学检查，以证实成像观察。在我们的初步数据中，观察到与非照射肾脏相比，照射肾脏中乳酸的产生减少，这表明可能使用超极化C-13代谢成像技术来检测肾脏组织中的辐射效应。

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. Recent introduction of nuclear hyperpolarization technique to liquid state enabled in vivo detection of C-13 labeled endogenous metabolites by MR spectroscopy imaging (MRSI). We investigate feasibility of employing this novel technique to assess radiation-induced tissue damage, which could result in radiotherapy, at moderate doses. We choose kidney tissues because kidney is a radiosensitive organ and provides internal control. In this study, we use Wistar male rats weighing 200-450 g to make the model by unilaterally irradiating one kidney with a collimated beam of X-rays. Initially, rats received radiation dose of 15 Gy and were subjected to C-13 magnetic resonance spectroscopy imaging (MRSI) at 21 days of postirradiation time. In MRSI, rats were intravenously injected with a hyperpolarized solution of 80 mM [113C]pyruvate. Hyperpolarization was performed by using DNP technique in HyperSenseTM polarizer (Oxford instruments). Fast chemical shift imaging (CSI) was performed at 3 T to acquire axial slices through both kidneys in every 6th second to measure both dynamic and spatial distribution of metabolites, pyruvate, lactate, and alanine. Animals are sacrificed after imaging to harvest kidney tissues for histopathology in order to confirm imaging observations. In our preliminary data, observed reduction of lactate production in the irradiated kidney in comparison to non-irradiated kidney suggests potential use of hyperpolarized C-13 metabolic imaging technique to detect radiation effects in kidney tissues.