Authors: P.A. Jackson, M. Geso
Affilation: RMIT University (Royal Melbourne Institute of Technology), Australia
Pages: 77 - 80
Keywords: gold nanoparticles, dual energy, Monte Carlo
There has been recent interest in the use of gold nanoparticles as contrast media in cancer diagnosis. This utilises either a high-concentration suspension to highlight all areas of vasculature or as an antibody-conjugated species with specificity for certain types of tumour cells. Modern dual-energy CT imaging protocols implement simultaneous scans using two x-ray sources with different tube potentials allowing the differentiation of materials on an elemental basis. This technique has been successfully employed with iodinated contrast media to digitally highlight or even remove its appearance from the recorded compound image set. Using Monte Carlo simulation, we have investigated an imaging protocol designed to highlight the presence of gold atoms in a tissue phantom. Gold’s K- and L-edges occur at 80.7 and 11.9 keV, requiring special consideration in order to remove its appearance from the low-kVp image while maintaining a high level of contrast relative to other anatomical features in the high-kVp image. In the investigated protocol, thin gold and copper filters are used to increase the spectral discrepancy between the low and high energy image sets. Subtraction image results show comparable contrast enhancement to conventional imaging parameters using iodinated CM while still removing the appearance of confounding anatomical structures.