Printing anthropomorphic multi-energy CT phantoms for spectral imaging with office laser printers

Spectral CT systems enable material decomposition (MD) and generate material-specific images and virtual monoenergetic images (VMIs). Multi-energy CT (MECT) phantoms with accurate attenuation properties enable image quality evaluation and optimization of these spectral CT systems. Previous works have proposed radiopaque 3D printing methods that print potassium iodide (KI) solution on different types of papers using office inkjet printers to create realistic customized patient phantoms of different anatomies. However, these methods failed to reproduce the accurate energy dependent x-ray attenuation properties of different human tissues and can only be used in conventional CT systems. The KI solution used in this inkjet printing technique also results in clogged printer nozzles and leads to inconsistent printed structures and high cost of printer maintenance. In this work, we propose a 3D anthropomorphic MECT phantom generation process with office laser printers and customized iron oxide toner. These phantoms reproduce realistic patient anatomical structures and accurate energy dependent attenuation properties of different tissue types. We printed a 5 mm thick slice of a non-contrast anthropomorphic brain phantom to validate our method. This printed phantom was imaged using two different x-ray spectra, which were used to form VMIs. Our results show that our method can print customized anthropomorphic MECT phantoms for spectral imaging with accurate energy-dependent x-ray attenuation properties.