Jelnes R, Astrup A, Bülow J
Scand J Clin Lab Invest. 1985 Oct;45(6):565-8. doi: 10.3109/00365518509155260.
Local subcutaneous 133xenon (133Xe) elimination was registered in the human forefoot in 34 patients. The tissue/blood partition coefficient for Xe was estimated individually by simultaneous registration of 133Xe and [131I]antipyrine ([131I]AP) washout from the same local depot. When measured in this way, an average partition coefficient for Xe was found to be 4.3 +/- 1.23 ml g-1. This value is significantly lower than the partition coefficient found in a previous in vitro study in which a Xe partition coefficient of 7.5 +/- 1.57 ml g-1 was found. Thus, if the local blood flow is calculated using the partition coefficient found by the double isotope technique, significantly lower values are obtained than if the in vitro determined coefficient is used. This difference is explained mainly by local dilution when injecting xenon subcutaneously. In short-term studies, utilization of the double isotope technique reduces the coefficient of variation on average flow determinations, thus an improvement in accuracy of local blood flow estimation can be obtained compared to the method in which an average partition coefficient is used. For long-term studies a partition coefficient of 7.5 ml g-1 seems valid.
对34例患者的人前足进行了局部皮下133氙（133Xe）清除率测定。通过同时记录同一局部储库中133Xe和[131I]安替比林（[131I]AP）的洗脱情况，分别估算了Xe的组织/血液分配系数。以这种方式测量时，发现Xe的平均分配系数为4.3±1.23 ml g-1。该值显著低于先前体外研究中发现的分配系数，后者发现Xe的分配系数为7.5±1.57 ml g-1。因此，如果使用双同位素技术测得的分配系数来计算局部血流量，所得到的值将显著低于使用体外测定系数时的值。这种差异主要是由于皮下注射氙时的局部稀释所致。在短期研究中，使用双同位素技术可降低平均血流量测定的变异系数，因此与使用平均分配系数的方法相比，局部血流量估计的准确性可得到提高。对于长期研究，7.5 ml g-1的分配系数似乎是有效的。
