A prototype of the MRI-compatible ultra-high resolution SPECT for in vivo mice brain imaging

In this paper, we will present a preliminary study based on a prototype of the MRI-compatible, ultra-high resolution SPECT system for use in a pre-existing Siemens 3.0 T MR scanner. The system uses an ultra-high special resolution energy-resolved photon-counting (ERPC) CdTe detector that we have recently developed. This detector consists of eight detector hybrids, each having a pixilated CdTe detector of 1mm thickness, bump-bonded to a custom-designed CMOS readout ASIC. Each detector hybrid offers an imaging area of 1.1cm x 2.2cm that is divided into an array of 32 x 64 pixels with a pitch size of 350μm x 350μm. A prototype SPECT system has been designed and tailored for use inside the 3.0 T Siemens scanner for tomographic imaging. It consists of a single ERPC detector head, coupled to a collimation aperture. The system is supported by a non-magnetic gantry that allows the system to be moved in and out the Siemens scanner and to be rotated around the object to obtain a sufficient angular sampling. All shielding, supporting and cooling structures are proved to be MRI-compatible. The imaging performance of the prototype system with presence of magnetic field will be evaluated by using image of the Co57 point source and the results will be presented.