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| – Information – |
| Micro-positron emission tomography (microPET) is a powerful tool for assessing cell, tissue, and organ function in vivo. Positrons, which are antimatter equal in mass but opposite in charge to an electron, are emitted from proton-rich nuclei. Depending on their energy, positrons travel an average distance (the annihilation distance) before interacting with an electron (matter). When the matter (electron) and antimatter (positron) collide (Figure 1), two anti-parallel 511 keV photons are emitted. It is these 511 keV photons that are detected by the ring of detectors on a PET scanner. Only photons that hit detectors 180˚ apart and at the same time are considered "true" counts, hence the term "coincidence counting." Although not always appreciated, the density of electrons in a tissue will have a profound effect on the annihilation distance, with less dense tissues like lung having a longer distance, and thus, lower inherent resolution. |
Proton-rich PET radionuclides are synthesized in particle accelerators (e.g., cyclotrons) or in nuclear generators. These positron emitting-radionuclides are attached to molecules of interest (molecular probes), or in some cases the radionuclide itself is the probe (e.g., 124I 2 or Na 18F). The key features of common PET radioisotopes are shown in Table 1. Since most PET isotopes are difficult and expensive to synthesize, or have extremely short half-lives, they are not routinely available. The exception is 18F, which has a 110-minute half-life and which is available in many chemical forms. The form 2-deoxy-2-[ 18F]fluoro-D-glucose ( 18FDG) is the most commonly used PET compound because it is taken up by cells similarly to glucose, but is not metabolized and is trapped inside after phosphorylation by hexokinase.
Please click her for a downloadable table of Table 1: Pet Isotopes arranged by increasing half-lives.
When isotopes are used in combination with a microCT scanner, investigators can quantify the exact amount of radioactivity in any organ or tissue of interest in a living animal. The key variables to a successful experiment are the chemical form of the positron-emitting isotope, the half-life of the radioisotope relative to the process under study (typically within 1-2 half-lives), the amount of radioactivity injected, the specific activity of the injected isotope, the spatial resolution of the microPET scanner, the sensitivity of the detection system of the microPET scanner, and the energy discrimination, that is, the ability to reject photons far from 511 keV. |
Figure 1: Positron collision with an electron in tissue releases two anti-parallel (i.e., 180˚ apart) 511 keV photons (a.k.a., gamma rays). Each photon will arrive at position-sensitive detectors arranged in a ring. With permission from: Levin, Craig S. Primer on Molecular Imaging Technology. European Journal of Nuclear Medicine.Vol 32, No 14, 2005. |
| – Specifications –
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PET Detector
- Crystal material: LYSO
- Crystal Thickness (mm): 13
- Crystal Pixel Size (mm): 1.12x1.12
- Number of Crystals: 39,780
- Packing Fraction (%): 92
- PS-PMTs (256 channel): 24
- Axial FOV (mm): 95
- Extended Axial FOV (mm): 300 (With translational motion)
- Transaxial FOV (mm): 94
- Bore size (mm): 150
- Sensitivity at CFOV (%): 8.3 (250-750keV window)
- Resolution at CFOV (mm): <1.2 (Filtered Back Projection)
- NEC mouse: 720kcps
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X-ray CT System
- X-Ray Tube:
- Energy range (kV): 35-90
- Tube Power (W): 8
- Max. Tube Current (μA): 180
- Focal Spot Size (μm): 5(@4W) 9(@8W) Detector:
- Detector Material: Gd2O2S
- Detector Size (mm 2 ): 50x175 Variable Zoom:
- Transaxial FOV (mm): 35-120
- Voxel Size (μm): 9-37 Helical Scanning:
- Axial FOV (mm): 300
- Scout scanning capability
- Closed Cabinet X-ray System
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Acquisition Console
Integrated Intel Core 2 Quad 3GHz, 4 GB RAM
- 17” touch screen and keyboard
- GPU for real-time CT reconstruction
InVivoScope™ Workstation
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Multi-modality display and analysis suite
- Intel Core 2 Quad, 4 GB RAM
- Fully DICOM compatible
- Includes DICOM server and broswer
Options
- Minerve® animal handling
- Pathogen-free imaging environment
- ECG and Respiratory Gating
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24-hour notice is required for changing or cancelling an appointment, or you will be charged for the scheduled time.
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| – Rates –
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Bioscan NanoPET/CT
Academic users: $350.00 per hour plus cost of isotope; billing is in 1/2 hour increments.
MicroCT only: $200.00 per hour; billing is in 1/2 hour increments.
Corporate users: $500.00 per hour plus cost of isotope; billing is in 1/2 hour increments.
MicroCT only: $300.00 per hour; billing is in 1/2 hour increments.
All isotope prices are subject to change.
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| – Checklist and Forms –
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| The BIDMC and Longwood SAIF are murine viral pathogen-free and endo/ectoparasite-free animal facilities. All incoming animals must be of the identical health status. Prior to acceptance and transport of rodents to the BIDMC and Longwood SAIF a recent (within 3 months) health report must be submitted and reviewed by the BIDMC veterinarian. All decisions regarding animal import are at the discretion of the BIDMC veterinarian, and are final.
Checklist
Import Request Form
Transport Request Form (For BIDMC SL3 ARF only; all others must use the Import Request Form)
Customer Survey
Boiler Plate Language for Animal Protocol Amendments
Boiler Plate Language for Grant Applications and Papers
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Animals transported from BIDMC SL3* ARF |
Animals transported from within BIDMC but not SL3* ARF |
Animals transported to the BIDMC from an OUTSIDE institution |
Long-term studies
(> 1 day) |
- Animals can move back and forth with approved BIDMC protocol/amendment
- Only Transport Form is needed |
- There is no long-term imaging of animals currently available, however, a satellite animal facility will open in summer 2007
- An approved BIDMC protocol/
amendment, Import Form, and Health Report will be needed to use the satellite facility once it opens |
- There is no long-term imaging of animals currently available, however, a satellite animal facility will open in summer 2007
- An approved Institutional protocol/
amendment, Import Form, and Health Report will be needed to use the satellite facility once it opens |
Short-term studies
(<1 day) |
- Animals can move back and forth with approved BIDMC protocol/amendment
- Only Transport Form is needed |
- Animals can be imported once (terminal experiment) with an approved BIDMC protocol/amendment
- Import Form and Health Report are needed |
- Animals can be imported once (terminal experiment) with an approved Institutional protocol/amendment
- Import Form and Health Report are needed |
*SL3 – BIDMC Slosberg-Landay 3rd floor Animal Research Facility.
The Longwood SAIF cannot accept any animals from the Thorn building or other, similar facilities. |
Other Notes:
- Previously euthanized animals or tissue specimens can be imaged if they are placed in a sealed plastic bag prior to shipment and must remain in the plastic bag while imaged; they must then be placed in a second plastic bag prior to disposal without protocol/health forms (i.e., animals can be imaged post mortem).
- After an animal has been euthanized, it can be taken back to its originating institution by the client for necropsy/histology.
- For short-term studies, all animals must be euthanized after imaging. In rare instances and only with written approval by the BIDMC veterinarian, live animals can be returned to their originating institution if a certain procedure in the approved animal protocol can be performed only at the originating facility and its endpoint is euthanasia by the end of the day (e.g., reperfusion of animal with formaldehyde for histology).
- Currently there is no overnight housing of animals at the BIDMC Animal Research Facility (Slosberg-Landay 3) until the completion of the new satellite facility (expected in summer 2007). Animals will only be accepted into the satellite if they are free of rodent viruses, endoparasites, and ectoparasites as per a recent health report.
- Animals that will come into the new, long-term satellite animal facility cannot be moved back to the SL3 facility without 8 weeks of quarantine. |
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