Perfusion phantom for the optimization of dynamic contrast-enhanced dedicated breast CT: Iodine contrast curves in a simplified breast phantom

Dynamic contrast-enhanced breast CT (DCE-bCT) is a novel functional imaging technique that captures the wash-in and wash-out of an iodinated contrast agent in the breast. This information could be helpful for tumor diagnosis, treatment planning and response monitoring. However, the optimal acquisition and reconstruction protocol must be determined before clinical implementation. Therefore, this research aims to create a dynamic breast phantom that can simulate clinically relevant time-intensity curves (TICs) with known ground truth. A simplified breast phantom was developed using 3D printing with its outer shape based on a quality control phantom. Polylactic acid material was chosen for its properties similar to those of the skin in terms of x-ray attenuation. The phantom was filled with olive oil to simulate fatty tissue. The phantom was connected to a perfusion setup consisting of two syringe pumps to inject and withdraw contrast or water, tubing, and a container with a mixer. The setup was used with the DCE-bCT system and an Iomeron contrast solution. The theoretical curve was compared to the DCE-bCT-estimated curve and showed a similar shape but different maximum enhancement (8.62 vs 6.97 mg I/mL). In addition, four types of clinically relevant TICs were simulated using potassium-iodine as a contrast agent and monitored using an in-line optical spectroscopy system. To achieve accurate and repeatable TICs, the next step is to program the syringe pumps. Thereafter, the setup will be used in combination with a to-be-developed tumor phantom for further optimization of DCE-bCT.