KINETIC MODELING OF TISSUE HETEROGENEITY IN METABOLISM AND BLOOD FLOW STUDIES

[~(14)C]脱氧葡萄糖法定量测定的改进 脑葡萄糖消耗率和脑葡萄糖消耗率的测定 [14C]碘安替比林法测定脑组织局部率 使用PET和[18F]氟脱氧葡萄糖和15 O- 分别标记的水出现了一些特殊的问题。由于 PET扫描仪的有限空间分辨率和部分体积效应， 均匀组织中的放射性测量很少，如果有的话， 已实现。因此，这两种方法的一个明确假设是 组织同质性，不满足；这一假设经常被遗忘或 被忽视，对这些方法的严重误解和误用 结果就是。我们研究了组织异质性对 局部脑血流量和葡萄糖利用率的测定及 已经开发出数学模型来明确地解释组织 异质性。这些模型已经在仿真研究中得到了验证 目前正在人体和动物研究中得到验证。此外，我们 正在评估使用的特殊时间限制 [18F]氟代脱氧葡萄糖与正电子发射计算机断层扫描。这些研究的结果将 为我们提供必要的信息，以便选择最合适的 化学发光测量的动力学模型和最优实验方案 正电子发射计算机断层扫描的葡萄糖利用率和血流量。

Adaptations of the [14C]deoxyglucose method for the quantitative determination of local rates of cerebral glucose consumption and of the [14C]iodoantipyrine method for determination of local rates of cerebral blood flow for human use with PET and [18F]fluorodeoxyglucose and 15 O- labeled water, respectively, have presented some special problems. Due to the limited spatial resolution and partial volume effects of PET scanners, measurement of radioactivity in homogeneous tissues is rarely, if ever, achieved. Hence one of the explicit assumptions of both methods, that of tissue homogeneity, is not met; this assumption is frequently forgotten or ignored, and serious misinterpretations and misuses of the methods have resulted. We have examined the effects of tissue heterogeneity on determinations of local cerebral blood flow and glucose utilization and have developed mathematical models to explicitly account for the tissue heterogeneity. These models have been validated in simulation studies and are currently being validated in human and animal studies. In addition, we are assessing the special time constraints for the use of [18F]fluorodeoxyglucose with PET in man. The results of these studies will provide us with the necessary information for choosing the most appropriate kinetic models and optimal experimental protocols for the measurement of glucose utilization and blood flow with PET.