Development of Pre-Clinical SPECT for MRI

We describe a single photon emission computed tomograph (SPECT) which can be operated inside state-of-theart magnetic resonance imaging (MRI) systems. The combined SPECT/MRI system allows one to acquire simultaneously the data from both modalities and co-register the images in space and time. Unlike conventional SPECT systems, which use scintillators and photomultiplier tubes, the new SPECT is based on the semiconductor cadmium zinc telluride (CZT) and application specific integrated circuits (ASICs) - two technologies which are MR-compatible and almost insensitive to magnetic fields. The γ-radiation imaging system has a 3-cm diameter fieldof- view and allows one to acquire regional tomographic images in mice without moving the camera.