Abi-Dargham A, Laruelle M, Seibyl J, Rattner Z, Baldwin R M, Zoghbi S S, Zea-Ponce Y, Bremner J D, Hyde T M, Charney D S
Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut.
J Nucl Med. 1994 Feb;35(2):228-38.
Iodine-123-iomazenil binding to benzodiazepine receptors in human brain was measured with SPECT using kinetic and equilibrium methods.
In the kinetic experiments (n = 6), regional time-activity curves after a single bolus injection of the tracer were fit to a three-compartment model to provide estimates of the rate constants K1 to k4. The binding potential (equal to the product of the receptor density and affinity) was derived from the rate constants. In the equilibrium method (n = 8), the tracer bolus injection was followed by a constant tracer infusion to induce a sustained equilibrium state. The regional equilibrium volume of distribution was calculated as the ratio of the regional brain concentration-to-the free parent tracer steady-state plasma concentration. In three experiments, a receptor-saturating dose of flumazenil was injected for direct measurement of the nondisplaceable compartment distribution volume.
The kinetic and equilibrium method results were in good agreement in all regions investigated. Iodine-125-iomazenil binding potential measured in vitro in 12 postmortem samples was found to be consistent with SPECT in vivo measurements.
These studies demonstrated the feasibility of quantification of receptor binding with SPECT.
使用单光子发射计算机断层扫描（SPECT），采用动力学和平衡法测量了碘-123-伊马西尼与人脑苯二氮䓬受体的结合。
在动力学实验（n = 6）中，将示踪剂单次团注后的区域时间-活度曲线拟合到三室模型，以提供速率常数K1至k4的估计值。结合潜能（等于受体密度和亲和力的乘积）由速率常数得出。在平衡法实验（n = 8）中，示踪剂团注后进行持续的示踪剂输注以诱导持续的平衡状态。区域平衡分布容积计算为区域脑浓度与游离母体示踪剂稳态血浆浓度之比。在三个实验中，注射受体饱和剂量的氟马西尼以直接测量不可置换部分的分布容积。
在所有研究区域中，动力学和平衡法的结果均吻合良好。在12个死后样本中体外测量的碘-125-伊马西尼结合潜能与SPECT体内测量结果一致。
这些研究证明了用SPECT定量受体结合的可行性。
