Research Unit Medical Radiation Physics and Diagnostics, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
Research Unit Medical Radiation Physics and Diagnostics, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany.
J Nucl Med. 2016 Jan;57(1):122-8. doi: 10.2967/jnumed.115.160713. Epub 2015 Nov 12.
Dose coefficients of radiopharmaceuticals have been published by the International Commission on Radiological Protection (ICRP) and the MIRD Committee but without information concerning uncertainties. The uncertainty information of dose coefficients is important, for example, to compare alternative diagnostic methods and choose the method that causes the lowest patient exposure with appropriate and comparable diagnostic quality. For the study presented here, an uncertainty analysis method was developed and used to calculate the uncertainty of the internal doses of 7 common radiopharmaceuticals.
On the basis of the generalized schema of dose calculation recommended by the ICRP and MIRD Committee, an analysis based on propagation of uncertainty was developed and applied for 7 radiopharmaceuticals. The method takes into account the uncertainties contributed from pharmacokinetic models and the so-called S values derived from several voxel computational phantoms previously developed at Helmholtz Zentrum München. Random and Latin hypercube sampling techniques were used to sample parameters of pharmacokinetic models and S values, and the uncertainties of absorbed doses and effective doses were calculated.
The uncertainty factors (square root of the ratio between 97.5th and 2.5th percentiles) for organ-absorbed doses are in the range of 1.1-3.3. Uncertainty values of effective doses are lower in comparison to absorbed doses, the maximum value being approximately 1.4. The ICRP reference values showed a deviation comparable to the effective dose calculated in this study.
A general statistical method was developed for calculating the uncertainty of absorbed doses and effective doses for 7 radiopharmaceuticals. The dose uncertainties can be used to further identify the most important parameters in the dose calculation and provide reliable dose coefficients for risk analysis of the patients in nuclear medicine.
辐射防护委员会（ICRP）和 MIRD 委员会已经公布了放射性药物的剂量系数，但没有关于不确定性的信息。剂量系数的不确定性信息很重要，例如，用于比较替代诊断方法并选择以适当和可比的诊断质量导致患者暴露最低的方法。对于本文介绍的研究，开发了一种不确定性分析方法，并用于计算 7 种常见放射性药物的内部剂量的不确定性。
基于 ICRP 和 MIRD 委员会推荐的广义剂量计算方案，开发并应用了一种基于不确定性传播的分析方法，用于 7 种放射性药物。该方法考虑了来自药代动力学模型和先前在慕尼黑亥姆霍兹中心开发的几个体素计算体模的所谓 S 值的不确定性。随机和拉丁超立方抽样技术用于抽样药代动力学模型和 S 值的参数，并计算吸收剂量和有效剂量的不确定性。
器官吸收剂量的不确定度因子（97.5%和 2.5%之间比值的平方根）在 1.1-3.3 之间。与吸收剂量相比，有效剂量的不确定度值较低，最大值约为 1.4。ICRP 参考值与本研究中计算的有效剂量偏差相当。
开发了一种用于计算 7 种放射性药物吸收剂量和有效剂量不确定性的通用统计方法。剂量不确定性可用于进一步确定剂量计算中的重要参数，并为核医学患者的风险分析提供可靠的剂量系数。
