Imaging Performance of the MOLECUBES β-CUBE - a dedicated small animal PET scanner using monolithic LYSO scintillator

Abstract

The MOLECUBES β-CUBE scanner is the newest commercially available PET scanner for rodent imaging. The scanner is lightweight, modular and utilizes a small footprint, enabling bench-top imaging. Its PET detector comprises of an 8mm thick monolithic LYSO scintillator read-out by an array of 3.2 mm x 3.2 mm Hamamatsu silicon photomultipliers. The monolithic scintillator not only improves scintillator packing fraction, but also enables depth-of-interaction measurement that permits development of such a compact PET scanner. Arranged in 5 rings of 9 detectors, the scanner diameter of 7.6 cm and axial length of 13 cm make it suitable for imaging both whole body mice and rats. Initial scanner characterization demonstrates the scanner to have good sensitivity and excellent volumetric spatial resolution. NEMA point-source measurement provides a spatial resolution of $\lt 1$ mm and sensitivity of $\sim 12$% (255 - 765 keV) at the center of the scanner. It has good count-rate capability to permit static and dynamic imaging studies for both mice and rats. In combination with the X-CUBE - a dedicated highresolution small animal CT, it offers quantitative imaging with spatially co-registered fully 3D PET-CT images.