Lag measurement in an a-selenium active matrix flat-panel imager.

摘要

Lag and residual contrast have been quantified in an amorphous selenium active matrix flat-panel imager as a function of frame time, kilovoltage (kV) and megavoltage (MV) x-ray photon energy and amount of incident radiation. The detector contains a 200 mum thick a-Se layer deposited on a thin film transistor array of size 8.7 x 8.7 cm2 with an 85 mum pitch.; For all energies, the lag for the n = 1 and n = 2 frame after exposure ranges from 0.45 to 0.91% and from 0.29 to 0.51%, respectively. The amount of lag was determined to be a function of the time after exposure irrespective of frame time or magnitude of exposure. The lag for MV energies was slightly less than that for kV energies. The residual contrast for all energies studied ranges from 0.41 to 0.75% and from 0.219 to 0.41% for the n = 1 and n = 2 frame, respectively.