Thalidomide is a sedative drug discovered at the end of the 50s, it showed high anticancer activity so attempts were made to synthesize thalidomide analogs that had fewer side effects than the parent compound. DPDQA showed higher anticancer activities than thalidomide. Labeling of a DPDQA with ^99mTc using Na₂S₂O₄ as reducing agent was performed. The dependence of the radiolabeling yield on the concentrations of DPDQA and reducing agent, pH of the reaction mixture, reaction time, and reaction temperature was studied. Bio-distribution studies in mice with tumor induced in the right thigh were carried out. The tumor infected thigh/contralateral thigh uptake ratio (T/NT) was evaluated. The time for the maximum accumulation of the ^99mTc–DPDQA in the tumor site was evaluated after administration of the compound.