重卤素核素~(211)At的制备及快速标记
THE PREPARATION AND FAST LABELLING OF HEAVY HALOGEN NUCLIDE 211At
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摘要: <正> 砹是一个无稳定同位素的重卤素元素,它既具有某些金属的性质,又具有卤素的特性。砹可以直接取代碘化物中的碘,生成多种砹化合物。在砹的二十余种同位素中,~(211)At的半衰期较长(T_(1/2) =7.2h),它的α衰变分支比为42%,K电子俘获分支比为58%。K俘获产物~(211)Po是半衰期为0.56s的纯α放射体。故也可以把~(211)At视为纯α放射体。它的α粒子平均能量为6.8Abstract: Bombardment of 26 MeV a beam on bismuth of natural abundance is carried out on the 1.2m cyclotron in Atomic Energy Institute to produce the heavy halogen nuclide 211At by the reaction 209Bi (α, 2n) 211At. The bombardment is followed by dry distillation at a temperature of 560-700℃ to extract the 211At from the irradiated target. 211At is then ob-sorbed in a solution of 0.1M NaOH and 0.05M Na2SO3 to obtain Na211At solution. The half-life of 211At is determined and the a energies of 211At and its EC daughter 211Po are identified.The product is then used to label NCL-6-I for forming a new compound NCL-6-211At by isotopic exchange in the presence of crown ether. Finally, an animal distribution test is carried out with the new compound. The results show that the compound is selectively concentrated in the adrenal gland. It seems that the compound NCL-6-211At is promissing for biological applications.