time of flight

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time of flight

the time for a photon created by annihilation of a positron-electron pair to reach a detector; because annihilation photons are created in pairs and travel in opposite directions at about 3 × 1010 cm/sec, measurement of the difference in arrival time at detectors with subnanosecond resolution allows calculation of the location of the event; the basic physics of positron emission tomography.

time of flight

An MRI term referring to a magnetic resonance angiography technique based solely on the flow of unsaturated blood into a magnetised presaturated slice. The difference between the unsaturated and presaturated spins creates a bright vascular image without needing contrast media.

time of flight

(tīm flīt)
magnetic resonance imaging Rate of flow in a given time; causes some flowing nuclei to receive only one radiofrequency pulse and therefore produce a signal void.