Design and Initial Performance Evaluation of a Large-Animal Dynamic SPECT/CT Imaging System

Comparing with small animals, large animal models are more suitable for a variety of translational research. For large animal, existing SPECT systems are less optimal, due to limited FOV, spatial resolution and/or sensitivity. With the development of pharmacokinetics research, dynamic imaging capability becomes more and more important. Dynamic imaging requires high sensitivity and stationary structure, which conventional SPECT systems often do not possess. In this work, we aim at developing a large-animal dynamic SPECT/CT system with multi-pinhole collimators. The large animal SPECT consists of six stationary clinical SPECT detectors arranged in hexagon (radius: 470mm). The large FOV collimator consists of six 2×4 pinhole groups whose position and opening angle are designed to cover whole FOV (Φ200mm×300mm). The theoretical calculation and simulation are performed to evaluate performance of the collimator. For large FOV collimator, spatial resolution and sensitivity over pinhole diameter curves are calculated and pinhole diameter is determined to 2.7mm. In the center of FOV, spatial resolution is 5.9 mm and sensitivity is 0.0393%. In the hotrod phantom (3.0~5.5mm) simulation, 3.0mm hotrod can be clearly distinguished. The proposed system has capability to realize large animal dynamic imaging. The multi-pinhole collimator was designed and performance were evaluated by calculation and simulation. The prototype system with two detectors will be accomplished to perform preliminary experiment.