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Positron from FDG and an electron combine to create two 511keV photons. If the signals arrive within nano seconds they are accepted to create the image. This process is called ‘electronic collimation’ and is what makes PET so sensitive.
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Positron from FDG and an electron combine to create two 511keV photons If the signals arrive within nano seconds they are accepted to create the image. This process is called ‘electronic collimation’ and is what makes PET so sensitive The light flash is converted to an electrical signal in the photomultiplier tubes Much more signal amplification takes place in the photomultiplier tubes coincidence The signal is amplified in the photomultiplier tubes Scintillating crystals connected to photomultiplier tubes Crystals create a flash of light when 511keV photons hit patient Pet scanners consist of rings of detectors, composed of photomultiplier tubes connected to scintillating crystals, that circle the patient. Here we see 2 such opposing detectors in one ring. The 2 signals from the photomultiplier tubes are fed into circuitry that defines the time difference between signals