Abstract: Two different dispersing methods are used to prepare ~(188)Re-rhenium sulfide suspension, with obviously different particle-size distribution. Swirling device, offersus large-sized particles, 55% of which are larger than 5 μm, 19% are larger than 10 μm. However, ultrasonic dispersion can only produce suspension with large quantities of smaller particles, only 0.3% of which are larger than 10 μm and almost 93% are within 5 μm. The former suspension made by swirling device appears deposition within 6 minutes, and the other is not uniform after 15 minutes, which radiochemistry purity and particle-size distribution do not change distinctively within 24 hours. The conclusion is that both of the suspension should be regarded as radiopharmaceuticals for testing the optimal particle-size ranges for intra-articular injection.