Vera D R, Scheibe P O, Banin Y, Stadalnik R C
Department of Radiology, University of California, Davis Medical Center, Sacramento 95817.
IEEE Trans Biomed Eng. 1994 Sep;41(9):891-7. doi: 10.1109/10.312097.
Local identifiability was determined for a receptor-binding radiopharmacokinetic system that included measured parameters of known uncertainty. Healthy subjects and patients with severe liver disease were studied with [99mTc] galactosylneoglycoalbumin (TcNGA). Measurements during the 30-min dynamic imaging study included the count rate over liver and heart, the quantity of TcNGA injected Lo, and the fraction-of-injected dose per liter of sampled plasma f. Typical relative standard deviations for these measurements were 1, 0.2, and 5 percent, respectively. A four-state nonlinear model describing the hepatic and plasma time-activity data was then used to calculate the standard error se(pj) for model parameters representing receptor concentration [R]o, the TcNGA-receptor forward binding rate constant kb, extrahepatic plasma volume Ve, hepatic plasma volume Vh, and hepatic plasma flow F. Accounting for the measurement uncertainties of Lo and f did not significantly increase the standard errors for parameters [R]o, kb, Ve, Vh and F. When the relative errors of Lo and f were increased to 40%, the change in se(pj) ranged from 10 to 100%, with parameter Vh being the most sensitive. The exception was se(kb), the increase of which was less than 1%. Imaging studies with reduced [R]o, typically associated with patients with liver disease, resulted in greater increases in all estimated parameter errors except se(kb) which had a lower increase. Lastly, the error propagation introduced by direct measurement of the liver observational coefficients sigma 12 and sigma 13 was investigated by simulating changes in the relative standard deviation in parameters sigma 12 and sigma 13 from 0 to 40%. Imaging studies from healthy subjects showed no increase in se(pj).(ABSTRACT TRUNCATED AT 250 WORDS)
针对一个包含已知不确定度测量参数的受体结合放射性药物动力学系统，确定了局部可识别性。使用[99mTc]半乳糖基新糖白蛋白（TcNGA）对健康受试者和严重肝病患者进行了研究。在30分钟动态成像研究期间的测量包括肝脏和心脏的计数率、注入的TcNGA量Lo以及每升采样血浆中注入剂量的分数f。这些测量的典型相对标准偏差分别为1%、0.2%和5%。然后使用一个描述肝脏和血浆时间 - 活性数据的四态非线性模型来计算代表受体浓度[R]o、TcNGA - 受体正向结合速率常数kb、肝外血浆体积Ve、肝血浆体积Vh和肝血浆流量F的模型参数的标准误差se(pj)。考虑Lo和f的测量不确定度并未显著增加参数[R]o、kb、Ve、Vh和F的标准误差。当Lo和f的相对误差增加到40%时，se(pj)的变化范围为10%至100%，参数Vh最为敏感。例外的是se(kb)，其增加小于1%。[R]o降低的成像研究通常与肝病患者相关，除se(kb)增加较低外，所有估计参数误差均有更大增加。最后，通过模拟参数sigma 12和sigma 13的相对标准偏差从0到40%的变化，研究了肝脏观测系数sigma 12和sigma 13直接测量引入的误差传播。健康受试者的成像研究显示se(pj)没有增加。（摘要截断于250字）
