Patent ID: 6051837
Filing Date: 2000-04-18
Classification: G01T

Abstract:
A method for identifying PMT drift in an edge PMT of a gamma camera wherein the camera includes a plurality of PMTs arranged in an array, the array including a central point at which, during a flood procedure, an intensity signal having intensity M is generated, a field of view FOV edge blocking at least a portion of the edge PMT, the PMT including a center point and at least one dimension over which the PMT intensity profile changes due to the blocked PMT portion, during an initial flood procedure, the PMT intensity profile including a first point at which the intensity level is N where N is a fraction of M, the method comprising the steps of, during a subsequent flood procedure:generating an updated intensity profile for the PMT;determining a second point on the second intensity profile at which the intensity level is N;comparing the first and second points:(a) where the second point is further from the center point than the first point, indicating that the PMT gain is too high; and(b) where the second point is closer to the center point than the first point, indicating that the PMT gain is too low.