Dhawan V, Poltorak A, Moeller J R, Jarden J O, Strother S C, Thaler H, Rottenberg D A
Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.
Phys Med Biol. 1989 Dec;34(12):1773-84. doi: 10.1088/0031-9155/34/12/002.
Unidirectional blood-to-brain and blood-to-tumour transport rate constants (K1) for 82Rb (half-life 76 s) and plasma water volume per unit mass of brain/tumour tissue (Vp) can be estimated in vivo using dynamic positron emission tomography (PET). The accuracy of these estimates depends upon the accuracy of PET measurements of regional brain/tumour radioactivity and scintillation well detector measurements of whole-blood radioactivity, which, in turn, depend upon the time course of arterial blood radioactivity. A two-compartmental model has been employed to derive estimates for K1, k2 (efflux rate constant) and Vp from 82Rb/PET data. Errors in these parameter estimates have been studied (1) qualitatively using sensitivity function analysis and (2) quantitatively using computer simulations. The effect of adding a third irreversible compartment and its unidirectional rate constant, k3, has also been investigated. The advantages and disadvantages of bolus injection vs continuous infusion protocols are discussed. Precision in estimated parameters from actual patient data is compared to that obtained from computer simulations in part II of this paper.
利用动态正电子发射断层扫描（PET）可在体内估计82Rb（半衰期76秒）的单向血脑和血瘤转运速率常数（K1）以及每单位质量脑/肿瘤组织的血浆水容量（Vp）。这些估计值的准确性取决于PET对局部脑/肿瘤放射性的测量精度以及闪烁井型探测器对全血放射性的测量精度，而这又取决于动脉血放射性的时间进程。已采用双室模型从82Rb/PET数据推导K1、k2（流出速率常数）和Vp的估计值。已通过（1）使用灵敏度函数分析进行定性研究和（2）使用计算机模拟进行定量研究来探讨这些参数估计中的误差。还研究了添加第三个不可逆室及其单向速率常数k3的影响。讨论了团注注射与连续输注方案的优缺点。本文第二部分将实际患者数据估计参数的精度与计算机模拟获得的精度进行了比较。
