<正>The synthesis and labeling of 99mTc-N3-(N'-[2-sulfanyl-ethylamino)acetyl]-2-aminoethyl-sulfanyl-1-hexanamide}thymidine (99mTc-NHT) were studied.In the presence of sodium glucoheptonate(GH) and ethylene diamine tetraacetic acid(EDTA),99mTc-NHT was obtained by using bisaminoethanethiol(N2S2) as a bifunctional coupling agent.The radiochemical purity of the 99mTc-NHT was over 95%.Biodistribution of 99mTc-NHT was performed in hepatoma HepA tumor-bearing mice.At 2 h p.i.,the ratios of tumor-to-muscle,tumor-to-bone and tumor-to-blood were 4.41±0.32,2.45±0.24 and 1.51±0.18,respectively.