Comparison of Gold Nanoparticles and Iodinated Contrast Media in Radiation Dose Reduction and Contrast Enhancement in Computed Tomography

Background: Gold nanoparticles with high atomic number and density have good potential to be used as contrast media in computed tomography. Objectives: In this study, we aimed to assess radiation dose and contrast enhancement performance of gold nanoparticles by measuring contrast to noise ratio compared to clinically used iodinated contrast agents at same concentrations. Contrast enhancement was evaluated in different tube voltages and currents. Materials and Methods: First, polyethylene glycol coated gold nanoparticles were synthesized with concentrations of 0.5 mM, 0.6 mM, and 0.7 mM. Gold nanoparticles and iodinated contrast media were scanned with CT imaging system at different tube voltages and time-current product. CT dose index (CTDI) value was measured by special phantom and electrometer. Improving in image contrast was assessed by contrast to noise ratio. Results: Results showed that gold nanoparticles in all concentrations and energies from 80 to 130 kVp display higher image contrast-to-noise ratio (CNR) than iodinated contrast media. Image CNR was increased by increasing kVp and mAs. The CNR value was maximum at the voltage of 80 and 130 kVp for iodinated compounds and gold nanoparticles, respectively. The CNR value for gold nanoparticles at 130 kVp and 200 mAs was approximately five times higher than that of iodinated compounds. Conclusion: Gold nanoparticles could be a good candidate for optimizing CT imaging by lowering radiation dose as low as possible while enhancing the image contrast.