We synthesized inorganic/polymer hybrid materials by a reverse microemulsion method for achieving multimodal contrast agent. Hybrid nanoparticles were synthesized with bio-responsive polymer and biocompatible layered double hydroxide (LDH) in nonylphenol ethoxylate (NP-9)/cyclohexane reverse microemulsion. Reverse microemulsion is liquid mixtures of water dispersed in oil with surfactant, micelles have the tails spreading out with the head groups at the center. Ratio of water to surfactant, W₀ was important to control the size and its morphology. Controlling the ratio enables us to synthesis nanometer sized hibrids with a 50-100nm diameter like round shape. Gd-DTPA and gallium species as metal radio isotope were introduced to this hybrid, in order to apply the contrast properties for computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) to one contrast agent. Powder X-ray diffraction (PXRD) patterns showed the crystal structure of typical LDH, and Fourier transform infrared (FT-IR) spectra were exhibited all kinds of chemical species were well introduced to this hybrid. It was verified that sizes of hybrids were 100-200 nm with spherical morphology by scanning electron microscopy (SEM).