The experimental study of biodistribution of iss Re-sulfide suspension with different particle size

Objective To evaluate biodistribution of ^188Re-sulfide suspension prepared with different particle size in normal rabbits in order to select an optimal particle size for intra-articular injection. Methods Two separate groups of a total 36 normal rabbits were injected intra-articularly into the knee joint with 22.2 MBq（0.2 ml） of the suspension. In 12 rabbits of group 1, all the animals were sacrificed at 10, 30 min and 5, 24 h （3 rabbits each） after injection of suspension Ⅰ preparated by ultrasonic dispersion. The other 24 rabbits received suspension Ⅱ dispersed by swirling device, and 6 rabbits sacrificed at each time. Then samples of various organs were obtained, weighed and their radioactivity was counted. Results Significant differences were detected during the first 10 min from the extra-articular leakages of radioactivity into lung, spleen and liver. Suspension Ⅱ produced far less uptake by these organs （0. 004,0. 003,0. 002 %ID/g ） than suspension I （0.05,0.04,0.10 %ID/g ）. Negligible leakages were found in other major organs throughout the whole study, such as brain, heart, testes etc. The above data indicated in dicated that radioactivity in the blood declined rapidly l0 min after administration and most of ^188Re-sulfide suspension were retained in the injected site, while the remaining of injected dose was excreted via kidney. Therefore the radiation injury of the nontargeting tissue was minimal. Conclusions The present study indicates that particle size of ^188Re-sulfide suspension plays an important role on extra-articular leakage, ^188Re-sulfide suspension dispersed by swirling device would be an attractive radiosynovectomy agent in terms of its lack of leakage, easy to prepare and quality controllable. Key words: Rhenium ;  Sulfides ;  Pharmacokinetics ;  Rabbits