Artificial compound-eye gamma camera for MRI compatible SPECT imaging

In this work, we proposed a next generation MRI compatible SPECT system, MRC-SPECT-II, based on an artificial compound eye (ACE) gamma camera design inspired by compound eyes often found in small invertebrate. The MRC-SPECT II had a very compact - 6cm detector ring size, but it consisted of 1536 independent micro-pinhole-gamma-camera-elements looking at the object. Each of the micro-camera-elements covered a narrow view angular in the object space. This system design could cover a FOV of 1cm diameter with a very rich angular sampling. Furthermore, the Monte Carlo study showed MRC-SPECT-II could achieve peak geometry efficiency of around 1.5% (as compared to the typical levels of 0.1%-0.01% found in modern pre-clinical SPECT instrumentations), while maintaining a spatial resolution of around 0.5 mm. Compared to the MRC-SPECT-I system that we have developed, the compact MRC-SPECT-II system could sit inside pre-clinical MRI scanner and potentially allowed us to take MRI and SPECT imaging at the same time. Also the dramatic increase in sensitivity could potentially lead to a radical change in how we might employ SPECT imagining in both pre-clinical and (potentially) clinical practice, by offering much lower detection limit and allowing for new imaging procedures that would be difficult to implement with the current generation of SPECT instrumentations.