Enabling Metabolic Imaging Using Feedback Driven Magnetic Resonance Spectroscopy

描述(由申请人提供)：糖酵解水平升高已知与各种癌症的存在和疾病阶段相关。这种现象被称为Warburg效应，为氟脱氧葡萄糖正电子发射断层扫描(FDG PET)研究提供了生物学基础。FDG以类似于葡萄糖的方式被细胞吸收，但随后会被困在细胞内超过一个小时。如果FDG分子中的19F原子已经被辐射到18F，那么它就可以使用断层扫描设备进行探测和空间定位。放射性18FDG PET已被证明能够在临床可用的设备上对长度为8 mm的肿瘤进行空间定位，并已被广泛应用于肿瘤的检测和分期超过30年。然而，它对患者造成了不小的辐射负担；因此，对人体的18FDG FDG PET扫描通常被限制为每个患者每12个月不超过一次，并且只有在已经进行组织诊断之后。需要在回旋加速器中制造放射性FDG，并提供对放射性材料的安全处理/处置，这大大增加了其固有成本。磁共振波谱成像(MRSI)技术也被用来在活体研究实验中检测和定位19FDG。这种方法不需要使FDG具有放射性；然而，由于MRSI研究中的信号要低得多，这种方法还没有转化到临床上。MKT正在开发一种方法，在一项MRSI研究中提高单位时间的信噪比。MKT技术利用众所周知的“超辐射”(SR)现象，也称为辐射衰减，在MRSI脉冲序列之后快速恢复磁平衡。这允许快速重复成像序列，从而可以增加随时间变化的平均信号。MKT的方法是在标准的临床磁共振成像设备中使用反馈使能电路(FEC)和位于共振线圈内的包含一定数量的目标分子的体积(称为补充自旋库(SSR))来产生SR条件，从而为感兴趣的分子(如FDG)创造SR条件。通过提高信号平均速率，我们改进了对目标分子的检测，并使使用MRSI来增强对FDG等氟化分子的检测成为可能。

DESCRIPTION (provided by applicant): Elevated levels of glycolysis are known to correlate with the presence and disease stage of various cancers. This phenomenon, known as the Warburg effect, provides the biological basis of Fluoro-Deoxyglucose Positron Emission Tomography (FDG PET) studies. FDG is taken up by the cell in a manner similar to glucose but then remains trapped in the cell for times exceeding an hour. If the 19F atom in the FDG molecule has been irradiated to 18F it can then detected and spatially located using the tomography device. Radioactive 18FDG PET has been shown to be able to spatially locate tumors on length scales down to approximately 8 mm in clinically available devices and has been widely used in the detection and staging of tumors for more than 30 years. However, it imposes a non-trivial radioactive burden on the patient; for this reason, 18FDG FDG PET scans for humans are typically limited to not more than once per 12 months per patient and only after a tissue diagnosis has already been made. The need to manufacture radioactive FDG in a cyclotron, as well as provide for safe handling/disposal of radioactive materials adds greatly to its intrinsic costs. Magnetic Resonance Spectroscopy Imaging (MRSI) techniques have been also used to detect and locate 19FDG in in vivo research experiments. This approach does not require the FDG be made radioactive; however, because of the much lower signal in an MRSI study this approach has not translated to the clinic. MKT is developing a method of improving the signal to noise per unit time in an MRSI study. The MKT technique leverages the well-known phenomenon of "super-radiance" (SR), also known as radiation damping, to rapidly restore magnetic equilibrium following an MRSI pulse sequence. This allows imaging sequences to be rapidly repeated so that the average signal over time can be increased. The MKT approach is to produce SR conditions in a standard clinical MR imaging device using a feedback enabled circuit (FEC) and a volume situated within the resonant coil containing a quantity of the target molecule, known as a Supplementary Spin Reservoir (SSR), to create SR conditions for a molecule of interest such as FDG. By increasing the signal averaging rate we improve detection of a target molecule and make it possible to use MRSI to enhance detection of fluorinated molecules such as FDG.