Nagaratnam A, Kaul A, Roedler H D
Defence Laboratory, Jodhpur, India.
Eur J Nucl Med. 1988;14(7-8):331-6. doi: 10.1007/BF00254378.
Radionuclide impurities of radiopharmaceuticals do not provide any diagnostic information, but contribute to the radiation dose to the patient. For 99mTc, even small amounts of long lived radionuclide impurities may contribute significantly to the dose from 99mTc itself. In this preliminary study, estimates have been made for the radiation dose to specific organs and for the effective dose equivalent from impurities in 99mTc-sodium pertechnetate prepared from fission product 99Mo. In addition to 99Mo, 131I, 103Ru, 89Sr and 90Sr at maximum permissible levels as stipulated in the European Pharmacopoeia, 110mAg and 239Pu were taken as representative nuclides for beta-gamma emitters and alpha emitters. Using all of these radionuclides at such maximum permissible levels of impurity as stated in the European Pharmacopoeia, the total contribution from the impurities to the effective dose equivalent is approximately 30% of the effective dose equivalent from 99mTc-pertechnetate. In terms of specific organs, the liver and kidneys can receive doses of 3-4 times and 1-3 times the dose from 99mTc-pertechnetate itself. Although these are worst case calculations, a consistent approach should be reconsidered to limit the additional effective dose equivalent from impurities to e.g. 10% of the effective dose equivalent from 99mTc itself.
放射性药物中的放射性核素杂质不会提供任何诊断信息，但会增加患者所接受的辐射剂量。对于99mTc来说，即使是少量的长寿命放射性核素杂质也可能对99mTc本身产生的剂量有显著贡献。在这项初步研究中，已经对由裂变产物99Mo制备的高锝酸钠中杂质对特定器官的辐射剂量以及有效剂量当量进行了估算。除了欧洲药典规定的最大允许水平的99Mo、131I、103Ru、89Sr和90Sr之外，110mAg和239Pu被用作β-γ发射体和α发射体的代表性核素。使用欧洲药典规定的这些杂质的最大允许水平下的所有这些放射性核素，杂质对有效剂量当量的总贡献约为高锝酸盐中99mTc有效剂量当量的30%。就特定器官而言，肝脏和肾脏所接受的剂量分别可能是高锝酸盐本身剂量的3 - 4倍和1 - 3倍。尽管这些是最坏情况的计算，但应该重新考虑一种一致的方法，将杂质产生的额外有效剂量当量限制在例如99mTc本身有效剂量当量的10%以内。
