Patent ID: 7873144
Filing Date: 2011-01-18
Classification: A61B,G01T

Abstract:
1. A radiographic imaging apparatus comprising: a primary radiation source which projects a beam of radiation into an examination region in which a subject is disposed for an examination, the primary radiation source having an ON state and an OFF state; a detector which converts detected radiation passing through the examination region into electrical detector signals representative of the detected radiation and a temporally changing offset B(t); an offset measuring circuit which measures a value (B a grid pulse circuit which turns the primary radiation source between the ON and OFF states at a rate between 1000 and 5000 pulses per second, such that the offset B(t) is re-measured between 1000 and 5000 times per second; a correction circuit which determines corrections to the detector signals to compensate for the temporally changing offset B(t) from the measured offset values and corrects the detector signals with the determined corrections.