PET CT Flashcards
a positron is a ____ _____.
a positron is a positively charged electron
what happens when the positron collides with an electron
an annihilation interaction
what is the most commonly used radionuclide in PET CT
fluorodeoxyglucose (FDG)
what is FDG a tracer for?
glucose metabolism
name two instances where glucose metabolism in cells are above baseline
within tumor cells and within infected cells
what does the annihilation interaction result in?
the production of two gamma rays of 511 keV each, released at 180 degrees to each other
what is the half-life of FDG?
110 Minutes
what is the basis of PET imaging?
positron emission, annihilation, with the emission of two photons 180 degrees apart
describe the detector in PET
Blocks of scintillation crystals arranged in a circle, mounted on a gantry, four PM tubes per detector block. scinitllator.
the block of scintillation crystal is subdivided into _____ _____
the block of scintillation crystal is subdivided into detector elements
what separates detector elements and why?
a reflective material separates the detector elements to prevent cross-talk of light photons between detector elements
what reads the signal from the crystal?
the PM tubes
why are PMTs the preferred photodetector?
they have high gain resulting in an electrical output with a good signal to noise ratio
