SPECT imaging properties of the CdTe-Timepix3 detector used in a new prototype FullSPECT 3D multimodal preclinical imaging system: Comparison with scintillation gamma camera

Small animal SPECT imaging represents a fast-evolving method for a noninvasive molecular imaging of metabolism, diseases, or malfunctions in live animal models. Preclinical imaging is important for translational research related to development and testing of new tracers, diagnostic and therapeutic methods for clinical application, and helps also in basic biological research. The small animal imaging requires better spatial resolution compared to human imaging. The improvement on the detector side should be implemented because the currently used scintillation gamma cameras are now touching their limits. The main goal of this work aims on introduction of a new concept of our prototype system (FullSPECT 3D) and comparison of the performance of its hybrid semiconductor Timepix3 based detector, and standard scintillation gamma camera in a commercially available device (Albira Preclinical Imaging System) for SPECT imaging on phantom and animal model. We compared both detector types on widely used 99mTc-HDP (for bone scan), and 125I labeled antibody biodistribution assays. The images taken with a single Timepix3 based detector were comparable and in some parameters exceeded standard detectors under similar geometry in 2D projections. The differences in 3D reconstructed images were not calculated because of the huge difference in the reconstruction algorithms, nevertheless the 3D images are shown as well. The future SPECT systems could benefit from the speed, energy resolution and size of Timepix3 based detectors and open the way to construction of very fast multimodal imagers requiring less ionizing radiation delivered to the patient.