Speaker
Description
Photon-counting computed tomography (PC-CT) is a next-generation imaging technology that enables material discrimination and localization with K-edge imaging by detecting individual X-ray photons along with their energy information. In a previous study, we developed one-dimensional PC-CT system consisting of multipixel photon counters (MPPCs) and yttrium-gadolinium-aluminum-gallium garnet (YGAG) scintillators with a matching 1 × 64 pixel size. This system successfully demonstrated material discrimination and concentration estimation in an object. However, the one-dimensional detector has a limitation in acquisition speed, making it impractical for medical applications.
In this study, we developed a two-dimensional PC-CT system employing a 1024-channel pixel array detector, composed of 16 × 64 pixels to realize fast and dynamic imaging. Signals from the MPPC are processed by an originally developed LSI whose performance has been validated through experiments with the one-dimensional PC-CT system. Performance evaluation revealed an average energy resolution of 40.7±2.1 % (FWHM at 59.5 keV) over the 1024 channels, and a count rate tolerance of 4.4±0.2 MHz, which are equivalent to those of the one-dimensional system.
Furthermore, as a preliminary experiment for application to dynamic imaging, in vivo imaging of mice injected with a gadolinium-based contrast agent, gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB), was performed. The imaging time was drastically reduced to ~1/10 of that of a one-dimensional system, demonstrating the feasibility of dynamic imaging. We will briefly report the detailed in vivo imaging evaluation results using the developed two-dimensional system.
