Russell C D
Division of Nuclear Medicine, University of Alabama Hospital, Birmingham 35233.
J Nucl Med. 1993 Oct;34(10):1761-5.
The best choice of sample times for measuring renal function in adults by single-injection multisample plasma clearance methods was determined by Monte Carlo simulation, using a two-compartment model with parameters chosen to fit average values (from published clinical studies) for each of the three radiopharmaceuticals 99mTc-MAG3, 99mTc-DTPA and 131I-ortho-iodohippurate. Random errors were added and the simulated data were then fit to a two-exponential model using a weighted nonlinear curve fitting method. The calculated clearance values were compared with the original values to determine random and systematic errors for different selections of sample time for each radiopharmaceutical at various levels of renal function. The results show that for research-level accuracy with a GFR agent such as 99mTc-DTPA, plasma sampling must begin by 10 min after injection and continue at least 3 hr (in adults). With an ERPF agent such as 99mTc-MAG3 or 131I-OIH, sampling must begin by 5 min and continue for at least 90 min. Six logarithmically distributed samples are sufficient.
通过单注射多样本血浆清除率方法测量成人肾功能时，样本采集时间的最佳选择是通过蒙特卡罗模拟确定的，采用两室模型，其参数选择为符合三种放射性药物（99mTc-MAG3、99mTc-DTPA和131I-邻碘马尿酸）各自的平均值（来自已发表的临床研究）。加入随机误差，然后使用加权非线性曲线拟合方法将模拟数据拟合到双指数模型。将计算得到的清除率值与原始值进行比较，以确定在不同肾功能水平下，每种放射性药物不同样本采集时间选择的随机误差和系统误差。结果表明，对于使用如99mTc-DTPA这样的肾小球滤过率（GFR）测定剂进行研究级别的准确性而言，血浆采样必须在注射后10分钟内开始，并持续至少3小时（成人）。对于使用如99mTc-MAG3或131I-OIH这样的有效肾血浆流量（ERPF）测定剂，采样必须在5分钟内开始，并持续至少90分钟。六个对数分布的样本就足够了。
