Room: Exhibit Hall
Purpose: This study evaluated the dependences of imaging contrast enhancement on the nanoparticle type, concentration, imaging beam energy and target thickness using the kilovoltage photon beams. This macroscopic study was carried out using the EGSnrc Monte Carlo code.
Methods: Monte Carlo simulation was used to model different nanoparticles (Au, Pt, I, Ag and Feâ‚‚Oâ‚ƒ), which were infused within a heterogeneous phantom (50 Ã— 50 Ã— 10.5 cmÂ³) with various nanoparticle concentrations (3, 7, 18, 30 and 40 mg/ml), imaging beam energies (mimicking a computed tomography source of 100, 120, 130 and 140 kVp) and thicknesses of target layer (0.5 â€“ 2 cm). The imaging contrast enhancement was determined by the imaging contrast ratio, defined as the ratio of imaging contrast at the target layer with added nanoparticles to the contrast at the layer without nanoparticles. The contrast ratios were predicted by Monte Carlo simulation regarding different nanoparticle types, concentrations, imaging beam energies and target layer thicknesses.
Results: Monte Carlo results showed obvious connection between a high nanoparticle concentration (40 mg/ml) and a high imaging contrast ratio, low imaging beam energy (100 kVp) and a high imaging contrast ratio, and a small target layer thickness (0.5 cm) and a high imaging contrast ratio. For all types of nanoparticles investigated, the gold nanoparticles were found to have the highest imaging contrast ratio of 3.7 with a concentration of 40 mg/ml using the 100 kVp photon beam.
Conclusion: It is concluded that the medical imaging contrast could be enhanced by increasing the contrast ratio using gold nanoparticles as the contrast agent to accomplish this improvement, using a high nanoparticle concentration, low imaging beam energy and a small target thickness.