RESUMO
Objective To prepare 99Tcm-B2-S22-AFA (99Tcm-TP1623)and investigate its biodistribution and kinetic imaging in healthy animals.Methods TP-1623 was synthesized and labeled indirectly by 99Tcm using stannous chloride as the reductive agent.The labeling rate was determined with chromatography using Whatman 3MM filter paper and by calculating the specific activity.The biodistribution of 99Tcm-TP1623 was tested at 1,5,10,30,60,120 min after intravenous injection into mice.According to the SPECT images and the time response of the radioactivity in the region of interest (ROI),the dynamic distribution of 99Tcm-TP1623 was assayed.Results The radiolabeling rate of 99Tcm-TP1623 was (96.4-± 0.1) ％ and the specific activity was (24.35 ± 0.06) TBq/mmol.After being conserved at room temperature for 4 h,the radiochemical purity of 99Tcm-TP1623 was (95.03 ± 0.97) ％.The oil-water distribution coefficient was-(2.51 ± 0.15).The bio-distribution test showed that the radioactivity in mice blood disappeared very fast over time by a quick excretion through renal.Meanwhile,the radioactivities in the heart,lung,liver,muscle and bone of mice decreased gradually along time and after 60 min they approached to the lowest levels.The radioactivity in brain always kept at a low level,but the radioactivity in intestinal increased slowly.For rabbits,the SPECT images showed that the radioactivity in blood disappeared quickly and the radioactivities were eliminated through kidneys.Meanwhile there were excretion images in gallbladder and intestinal,but no obvious nuclide accumulation in thyroids and stomach,and low radioactivity in brain as well.Conclusions 99Tcm-TP1623 is easy to prepare and has a high radiolabeling efficiency and good stability in vivo and in vitro,and it has excellent dynamic characteristics in normal animals.