A TRACER-KINETIC APPROACH TO ESTIMATE RADIATION DOSIMETRY OF 0-15 WATER

估算 0-15 水辐射剂量的示踪动力学方法

• 批准号: 3774468
• 负责人: P HERSCOVITCH
• 金额: --
• 依托单位: CLINICAL CENTER
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3774468
• 关键词: blood flow measurement; body water; brain circulation; cerebrum; child (0-11); computer simulation; human tissue; mathematics; method development; organ; positron emission tomography; radiation dosage; radiotracer; stable isotope

Previous dosimetry calculations have assumed that 0-15 water instantaneously equilibrates in the water space of the body (Annals ICRP 53:67, 1988). The initial distribution of 0-15 water depends on organ flow however, and it takes several minutes to reach equilibrium. Because 0-15 has a short half-life, the equilibrium assumption underestimates cumulated activity and radiation dose in high flow organs. We used a one-compartment model to calculate organ cumulated activity and mean residence times from organ blood flow and 0-15 water volume of distribution. Arterial time-activity curves were used from subjects undergoing rCBF measurements with bolus 0-15 water. Radiation dose estimates were obtained in collaboration with investigators at Oak Ridge Associated Universities. In contrast with previous estimates, high flow organs had substantially greater radiation doses, e.g., heart wall 8.2 mrad/mCi (vs. 2.1 in the literature), kidney 7.2 (2.1), lung 6.9 (2.0), thyroid 6.3 (1.9). This method is physiologically realistic and predicts organ residence times and dose estimates without requiring direct activity measurements. Verification of the method will be performed against organ time-activity curves from organs imaged for other purposes (e.g. brain, heart, lung), and the approach will be extended to obtain dose estimates in pediatric age groups.

以前的剂量计算假设0-15水 瞬间在身体的水空间中平衡（Annals ICRP 53：67，1988）。 0-15水的初始分布取决于器官 然而，它需要几分钟才能达到平衡。 因为 0-15半衰期短，平衡假设低估了 高流量器官的累积放射性和辐射剂量。 我们使用了 计算器官累积活性和平均值的一室模型 从器官血流和0-15体积的水的停留时间 分布 使用受试者的动脉时间-活动曲线 用推注0-15水进行rCBF测量。 辐射剂量 估计是与橡树岭的调查人员合作获得的 联合大学。 与先前的估计相比， 器官的辐射剂量明显更大，例如，心墙8.2 mrad/mCi（与文献中的2.1相比），肾脏7.2（2.1），肺6.9（2.0）， 甲状腺6.3（1.9）。 这种方法在生理上是现实的，可以预测器官驻留 时间和剂量估计，而不需要直接的活动测量。 将根据器官时间-活性进行方法验证 用于其他目的成像的器官的曲线（例如，脑、心脏、肺）， 该方法将扩展到获得儿科剂量估计 年龄组