Abstract: DEVELOPMENT OF99TcmDTPAOCTREOTIDE AS SOMATOSTATIN RECEPTOR IMAGING AGENT I. STUDYING OF LABELLING CONDITIONSCheng Zhen Lin Qiongfang Jin XiaohaiWang Fan Chen Daming Bai Hongsheng Fan Hongqiang Du Jin(Isotope Department, China Institute of Atomic Energy, Beijing 102413)ABSTRACTLabelling conditions of 99TcmDTPAoctreotide are studied, including pH value, temperature, time, various quantities of DTPAoctreotide and SnCl2·2H2O. The labelling yield can reach 90%. The labelling product could be further used for tumors SMS receptor imaging after purification. The paper chromatography and reverseHPLC for accurate and quick measurement of radiochemistry purity of products are investigated. Furthermore, the labelling product is a mixture consisting of several kinds of complexes proved by HPLC. The nature and proportion of the complexes depend on the labelling condition.Key words octreotide 99TcmDTPAoctreotide imaging agent labelling condition