Abstract: PREPARATION OF ~(125)I-LIPIODOLDu Jin；Jin Xiaohai；Chen Daming；Bei Hongsheng；Liu Yuemin；Wang Fan（China Institute of Atomic Energy，Bejjing 102413）ABSTRACT An isotopic exchange method has been used to label lipiodol with ~(125)I．The labelling efficiency ismore than 9 2％in the optimum condition（using ethanol as reaction medium，100℃，20 min ） andthe radiochemical purity of~(125)I- lipiodol is above 98％as detemined by TLC and HPLC. The labellingprocess does not change the chemical structure of lipiodol． The~(125)I- lipiodol is stable at least in onemonth at room temperature. Key words isotopic exchange reaction lipiodol~(125)I-lipiodol