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31 Cards in this Set
- Front
- Back
Positron Decay
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Have an excess number of protons
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Lie below the line of ______
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stability
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Require accelerator for
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production
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Two 511 keV annihilation photons are emitted _______ degrees
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180
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Electron Capture
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For lower transition energies, electron capture is an alternative decay mode for proton-rich isotopes.
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Unlike larger/heavier charged particles,the positron does not travel in a straight path
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It bounces around like billard ball
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Detector Block
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A group of crystals tied into a 1 detector with a PMT at the end
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PET Sinograms
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Sinograms make a lot more sense to the computers but not to us
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Sinograms and projection views are different ways of showing the __________ data
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same
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Each pixel in the sinogram corresponds to a particular ____________ or detector pair
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LOR/line of response
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Delayed time window
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a method for estimating and correcting the number of random in a PET acquisition
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this works to some extent but creates a very
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noisy correction adding to the overall NOISE of the PET image
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As the count rate increases (patient dose)
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randoms increase faster than true events
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Delay Window Method
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Estimated Trues = prompts - delays
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2D
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slower acquisition time
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2D
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limit scatter and gain in resolution
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3D
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septa are removed, a lot faster imaging time
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3 D PET __________ drops off toward the edges
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sensitivity
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4-5 x increased _________ overall
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sensitivity
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Increased _________ from out of field activity
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randoms
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Time of Flight
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LSO
LYSO GSO |
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Time of flight
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see notes......better for bigge3r patient bec. you have a larger %
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Larger patient you have
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3.3 x improvement
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PEM
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Positron Emission Mammography
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CHB MicroPET scanner
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done for research, mouse `
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PET MRI
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FDG Tumor imaging
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Summary
Modern scanners designed for __________ imaging |
oncology
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All PET/CT sales are now
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NO MORE DEDICATED PET SCANNERS
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New scintillation detectors combine excellent detection efficiency and _________ decay time
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short
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Shorter decay time lead to the possibility of ________
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time of flight PET
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_______PET scanners can provide very high spatial resolution with high sensitivity in small foot print and easy access to the research animals.
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MICRO
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