Imaging Core

Core Director:
Jeffrey Duerk, Ph.D.

The Small Animal Imaging Core will occupy ~8000 ft.2 of renovated space in the basement of Lerner Tower of UHC in close proximity to the Animal Resource Center and the Department of Radiology’s existing imaging program. The center is being constructed and operated through numerous federal, state, and institutional grants, including an earlier BRTT, on gastrointestinal cancers.

Imaging Systems and Capabilities

Magnetic Resonance Imaging and Spectroscopy:
MR capabilities include two (7.0T/9.4T) Bruker Biospec in-vivo imaging/spectroscopy systems. These systems have 30cm/20cm bores, respectively. Broadband excitation and receivers (4 channels) provide capabilities for advanced multi-nuclear (1H/19F/13C/23Na/2D/31P) imaging and spectroscopy. Applications include in-vivo proton and phosphorus metabolism, measurement of tissue perfusion, in-vivo spatially resolved estimation of pH, etc. The systems are equipped with pulse sequence design and development software, as well as ECG, respiratory gating capabilities for motion-sensitive examinations, high-resolution imaging of the brain, and/or heartbeat-synchronized ultra-fast imaging. A full-body human 4.0T scanner is also part of the center to support increased SNR/resolution as compared to current clinical systems and to facilitate translational research to patients. The system will also be equipped with pulse sequence software for flexibility for research applications. A radiofrequency electronics design and fabrication laboratory is available to produce custom transmit / receive coils for specific MRI/MRS imaging applications.

MicroPET:
An R4 micro-PET system (Concorde Microsystems, Inc, Knoxville, TN) will provide high sensitivity (~900cps/uCi) and high resolution (~2mm) PET imaging capability. MicroPET can be used for very high sensitivity in-vivo estimation of, FDG/Glucose metabolism, perfusion, etc. in mice, rats, cats, rabbits, groundhogs, etc. The R4 has a bore diameter of 12cm and an axial field of view of ~10cm provided by 6144 high-resolution LSO detectors arranged into 64-element blocks. The scanner has no septa and operates solely in 3D mode. The scanner includes a computer-controlled animal bed, a laser alignment system, and software for data collection, correction, reconstruction and analysis.

MicroSPECT/CT:
This second generation scanner is a dedicated purpose-built small animal combined CT and SPECT imager (Gamma Medica) specific for high-resolution in vivo imaging in the animal-laboratory setting. Detectors and the x-ray tube rotate around the horizontal subject. Co-registered images are acquired without removing the animal from the imaging system, thereby preserving registration. It can record SPECT images from more than one radionuclide simultaneously for probing multiple receptor systems simultaneously using isotopes that emit photons of different energy.

Scintigraphy:
The prototype planar scintigraphy system from Thomas Jefferson National Lab combines X-ray and planar gamma scintigraphy to map functional information on anatomical references, using a special x-ray tube and matched flat panel detector. The scintigraphic portion consists of a pixilated crystal coupled with a position-sensitive PME. It is also equipped with high sensitivity copper collimator, particularly useful for I-125 imaging.

“Hot” Chemistry Lab:
A radiopharmaceutical lab is available for safe handling of radiotracers used in nuclear medicine. This lab is equipped with a pneumatic delivery system for fast and safe delivery of short half-life radioactive materials from the nearby cyclotron. The lab has a chemical fume hood, a 4C refrigerator, and a -20C freezer for handling and storage of radioactive materials and tissue samples.

Bioluminescence Imaging (BLI):
BLI measures targeted gene expression in-vivo by coupling the light emitting luciferase gene (or other reporter gene) to a specific gene of interest. The BLI imaging system (Roper Scientific, Inc.) consists of a liquid N2 cooled (below -115°C) CCD camera (Versarray 1024, with a 50-mm f-0.7 lens (Nikon, Japan)), light-tight sample chamber, controller, and data acquisition software. The CCD camera has a quantum efficiency of ~90% for photons having wavelengths 500-650 nm.

Fluorescence:
Funds from a recently awarded R24-SAIRP grant will be used to purchase or construct a high-resolution, high-sensitivity fluorescence system with multi-spectral capabilities for tracking gene expression from Xenogen. The fluorescence system will have a dark enclosure to allow the system to be used for bioluminescence as well. The remaining cost for this system is requested from the BRTT.

Optical CoherenceTomography (OCT):
OCT measures light scattering in opaque tissues with micron-scale resolution to depths of 1-2 mm. Images of living specimens are obtained at 8-32 frames/second; no contact is necessary between the probe and the sample. It can be used for imaging exposed tissue surfaces directly or via a miniature catheter probe for endoscopic imaging. The instrument also images in alternative contrast modes, including Doppler (blood flow in microcirculation), polarization-contrast (form-birefringence contrast in neural, skeletal/muscle) and spectroscopic contrast (hydration and oxygen saturation). Multiple OCT systems are also available for patient research.

Animal Welfare:
The center houses 4 individual animal holding/preparation rooms to quarantine specific colonies/species, each equipped with a class II biological safety cabinet to protect both animals and researchers from airborne pathogens and chemical vapors. Multiple gas anesthesia systems provide remote, controllable sedation (isofluorane) to multiple animals simultaneously from gas manifolds and distribution systems. Multiple laptop computer systems monitor/control respiration, EKG, and body temperature during experiments. A blood sampling device is also available for pharmacokinetic studies.

Computer:
Other high-end PC computers and image analysis software programs are available within the Center. Software analysis tools are developed at sites such as Matlab, Analyze and IDL and are engineered in-house for specific imaging applications. All labs and offices are wired to access the Case fiberoptic network for high-speed transmission and archiving of images and data. A 1.4TB image archive system is also available. Images will be accessible via a web-based database that will provide imaging study results as well as cost and scheduling capabilities.