A PET/SPECT/X-ray prototype for whole body mouse imaging

Introduction In this work we present a hybrid, prototype SPECT/PET/CT system, suitable for whole-body small animal imaging. The integrated SPECT/PET/CT system has three components and is mounted on a computer-controlled rotating gantry. Purpose The main goal of this work is to provide a robust infrastructure for animal studies on national and regional level. Materials and methods The SPECT component is based on two H8500 Position-Sensitive-Photomultiplier-Tubes, a 1 × 1 × 5mm 3 NaI(Tl) pixelated scintillator and a general purpose hexagonal collimator. The PET components are based on the same PSPMTs coupled to 2 × 2 × 5 mm 3 BGO pixelated scintillators. The X-Ray detector is a high speed, low noise and high sensitivity flat panel detector, model C10900D-40 from Hamamatsu. It is based on the CMOS technology and it is suitable for real-time static and CT imaging with high dynamic range. The X-ray tube, SourceBlock™ by Source-Ray Inc, integrates an X-ray tube and a high voltage generator into one physical package. The SB-80-500 model has a 33 μm minimal focal spot, a variable voltage 35–80 kVp and 20–500 μA current. Results The SPECT system has been evaluated with phantoms and small animals and has a 1.5 mm spatial resolution for 99m Tc, while it can provide fast images for dynamic mice studies. Two additional collimators allow imaging of higher energy isotopes. The spatial resolution of the PET system is equal to 2.5 mm, while further optimization is possible by using proper reconstruction algorithms and corrections. The X-ray system provides high resolution (10 μm) anatomical images of mice, which are fused with the functional images of PET/SPECT. Conclusions The presented system provides unique infrastructure to support preclinical research on national and regional level.