Photon-counting Computed Tomography of Lanthanide Contrast Agents with a High-flux 330-m-pitch Cadmium Zinc Telluride Detector in a Table-top System

We present photon-counting computed tomography (PCCT) imaging of contrast agent triplets similar in atomic number ( ) achieved with a high-flux cadmium zinc telluride (CZT) detector. The table-top PCCT imaging system included a -pitch CZT detector of size capable of using six energy bins. Four 3D-printed 3-cm-diameter phantoms each contained seven 6-mm-diameter vials with water and low and high concentration solutions of various contrast agents. Lanthanum ( ), gadolinium (Gd) ( ), and lutetium ( ) were imaged together and so were iodine ( ), Gd, and holmium ( ). Each phantom was imaged with 1-mm aluminum-filtered 120-kVp cone beam x rays to produce six energy-binned computed tomography (CT) images. -edge images were reconstructed using a weighted sum of six CT images, which distinguished each contrast agent with a root-mean-square error (RMSE) of and 0.51% for the 0.5% and 5% concentrations, respectively. Minimal cross-contamination in each -edge image was seen, with RMSE values in vials with no contrast. This is the first preliminary demonstration of simultaneously imaging three similar contrast agents with a difference in as low as 3.