The SARIC houses a state-of-the-art integrated small animal imaging platform for near simultaneous and co-registered radionuclide SPECT, PET and CT imaging (Inveon, Seimens). The Inveon (Siemens) imaging system is capable of true trimodal imaging guided by computer positions systems located within the gantry. The system has an integrated system for inhaled anesthesia and maintenance of isothermia. There is an onsite radionuclide hot lab for dosimetry, cold kit preparation, and storage. Typical applications include high-resolution CT anatomic imaging, cell tracking, perfusion imaging, molecular imaging, cell proliferation, enzyme activity, pharmacodynamics, gene profiling, and metabolic imaging.
The CT imaging system is a single integrated gantry with a 14 bit x-ray imaging detector with 4,096 X 4,096 pixels (10 X 10 cm FOV) for imaging not only small but large rodents. The system has variable focus x-ray source for spatial resolution down to 20 microns. There is also a high-performance work station with real-time and scalable reconstruction with 512 X 512 X 768 voxel volumes.
For SPECT imaging there is a 2-headed detector (15 X 15 cm) system for whole animal or high-magnification studies. Gamma ray detection range is from 30 to 300 keV. The system has a general purpose, mouse pinhole, and rat pinhole collimator.
For PET imaging, there is a high performance lutetium oxyorthosilicate (LSO) crystal detector with absolute sensitivity of 10% at the center of the FOV. The detector pixel spacing (1.59 X 1.59 mm) provides a 1.4 mm full width at half-maximum spatial resolution using a traditional filtered back projection algorithm. An axial FOV up to 30 cm is possible.
The research workplace software provides imaging review, image fusion (including 3-D fusion images of CT, SPECT and PET), and analysis packages. Radionuclide data can be processed with either filtered back projection or alternatively with iterative reconstruction (ordered-subset expectation maximization [OSEM]) processing for better signal-to-noise or shorter acquisition times. CT attenuation correction algorithms are used.
Although the director of the SARIC maintains a nuclear license for the facility, approval of all protocols employing radionuclides must be obtained through the Radiation Safety Office at OHSU. All investigators must be familiar with SARIC post-imaging handling procedures for animals receiving radionuclides.