A method for preparing an instant kit of 99mTc ( V ) DMSA was described. The effect of pH on labeling efficiency of the kit was investigated. 99mTc ( V ) DMSA was characterized by TLC on silicagel sheets , eluting with n-butanol : acetic acid : water = 3 : 2 : 3 (volume ratio). Radiochemical purity and stability of 99mTc ( V ) DMSA in vitro were studied. The results clearly demonstrated that the yield of 99mTc ( V ) DMSA was more than 95% at pH 8-8. 5 and the agent was stable in 3 h at room temperature. Eff...