Di Chiro G, Brooks R A, Patronas N J, Bairamian D, Kornblith P L, Smith B H, Mansi L, Barker J
Ann Neurol. 1984;15 Suppl:S138-46. doi: 10.1002/ana.410150727.
Over 150 cases of central nervous system tumors have been studied with positron emission tomography using fluorine-18-labeled fluorodeoxyglucose (18FDG) as a tracer. From this material 100 consecutive cases of cerebral glioma have been reviewed and analyzed. The results show a strong correlation of tumor grade with glycolytic rate, with visual "hot spots" present in all high-grade neoplasms and in only four low-grade tumors. The quantitative accuracy is limited by three basic factors. First, the measurement of tissue uptake, as compared with the parent technique, autoradiography, is more difficult because detection must be done outside the body. Effects such as scattered radiation and self-attenuation introduce errors unless properly corrected. A more serious problem when measuring small structures, such as a rim-shaped high-grade glioma, is the limited spatial resolution. The most advanced scanner, the Neuro-PET, has a resolution of 6 to 7 mm. Second, corrections are needed for backflow, including free tracer at the time of the scan that will return to the blood and "trapped" tracer that will backflow because of the presence of phosphatase. These corrections are calculated from the blood activity using nominal rate constants for 18FDG. Our study found no significant alteration in rate constants between normal and tumoral tissue. Finally, a lumped constant is needed to correct for kinetic differences between 18FDG and glucose. If there is a change in the mechanism of either membrane transport or the hexokinase reaction, the lumped constant may change. However, measurements of actual glucose utilization in tissue culture lines from six patients support the 18FDG results.
利用正电子发射断层扫描技术，以氟-18标记的氟脱氧葡萄糖（18FDG）作为示踪剂，对150多例中枢神经系统肿瘤进行了研究。从这些病例材料中，回顾并分析了100例连续的脑胶质瘤病例。结果显示肿瘤分级与糖酵解速率密切相关，所有高级别肿瘤均出现明显的“热点”，而低级别肿瘤中只有4例出现。定量准确性受到三个基本因素的限制。首先，与母体技术放射自显影相比，组织摄取的测量更加困难，因为检测必须在体外进行。除非进行适当校正，散射辐射和自衰减等效应会引入误差。在测量小结构（如边缘型高级别胶质瘤）时，更严重的问题是空间分辨率有限。最先进的扫描仪Neuro-PET的分辨率为6至7毫米。其次，需要对回流进行校正，包括扫描时将返回血液的游离示踪剂以及由于磷酸酶的存在而回流的“捕获”示踪剂。这些校正通过使用18FDG的标称速率常数根据血液活性来计算。我们的研究发现正常组织和肿瘤组织之间的速率常数没有显著变化。最后，需要一个集总常数来校正18FDG和葡萄糖之间的动力学差异。如果膜转运或己糖激酶反应的机制发生变化，集总常数可能会改变。然而，对6例患者组织培养系中实际葡萄糖利用的测量结果支持了18FDG的结果。
