Bassingthwaighte J B
Fed Proc. 1982 Dec;41(14):3040-4.
Techniques for estimating cellular uptake rates of substrates are now developed to the point where they can be used in a research setting. They are based on the use of the multiple indicator dilution technique, in which intravascular and extravascular reference tracer solutes are used simultaneously with the tracer substrate. The analysis involves fitting the dilution curves with mathematical models accounting for flow (and its regional variation), capillary permeation, dilution in the interstitial space, penetration of the sarcolemma of myocardial cells, and dilution and consumption inside the cells. The same principles and models are applicable to data in the form of externally detected residue function curves of the organ’s content of tracer as are suited to coronary sinus outflow concentration-time curves. The future developments will be in refining the external detection techniques, in making the studies less invasive and more suited to clinical studies. Multiple gamma photon imaging may be more useful than positron imaging for such studies because of the need to use simultaneous sets of tracers, including appropriate intravascular and extracellular references.
目前，用于估算底物细胞摄取率的技术已发展到可用于研究环境的程度。这些技术基于多重指示剂稀释技术，即在使用示踪底物的同时，还会同时使用血管内和血管外参考示踪溶质。分析过程包括用数学模型拟合稀释曲线，该模型要考虑血流（及其区域差异）、毛细血管渗透、间质空间稀释、心肌细胞膜的穿透以及细胞内的稀释和消耗。同样的原理和模型适用于以外部检测到的器官示踪剂含量残留函数曲线形式呈现的数据，这与冠状窦流出浓度-时间曲线类似。未来的发展方向将是完善外部检测技术，使研究的侵入性更小，更适合临床研究。由于需要同时使用多组示踪剂，包括合适的血管内和细胞外参考示踪剂，因此多重γ光子成像在此类研究中可能比正电子成像更有用。
