Bioquin-HMPAO (BH) was previously investigated as a novel brain imaging agent by in vivo biodistribution studies. Present studies are carried out to explore radiolabeling and in vitro behaviour evaluation of poly (lactic-co-glycolic acid) (PLGA) encapsulated BH nanocapsules (BH-PLGA NCs). BH-PLGA NCs were characterized utilizing dynamic light scattering and scanning electron microscope. Encapsulation effect on radiolabeling with Tc-99m was examined by stability and lipophilicity studies and effect on in vitro behaviour of Tc-99m-BH was evaluated by incorporation studies on DAOY, U87-MG and A549 cells. It is observed that PLGA encapsulation has a positive and reinforcement effect.