Optimization of Energy Combination for Gold-based Contrast Agents below K-edges in Dual-energy Micro-CT.

Dual-energy micro-Computed Tomography provides high resolution non-invasive images at low cost. It can determine the concentrations of component materials in a mixture. Taking the advantages of K-edge, the gold-based agents contribute to improve the contrast of some physiological tissues with low natural contrast. Because the K-edge of gold (80.7 kVp) is excessively high, the anatomical structures could not be identified clearly in in vivo small animal experiments. In this study, the energy combination below K-edge is optimized to differentiate bone, soft tissue and gold. Furthermore, we evaluate the effects of concentration of contrast agents, the extrinsic filtration setting and dose level. Based on the quantitative analysis results of material decomposition, the optimized energy pair gathered in a certain range where the low-energy is 30kVp-40kVp. Our results can provide a practical guidance for the design of in vivo small animal experiments using gold-based contrast agents.