Systems and methods of determining focal spot x-axis position from projection data
AssigneeGeneral Electric Company
InventorMichael Floyd Gard
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Abstract
The present invention, in one form, is a method of determining focal spot position in a computed tomography system using conventional scan data. The computed tomography system includes, in one embodiment, a bowtie filter attenuating an x-ray beam along two symmetrically disposed raypaths. The symmetrical raypaths impinge upon respective detector channels at identifiable path lengths. The raypath lengths are compared to determine whether the focal spot has shifted.
Claims20
A computed tomography system comprising an x-ray source having a focal spot during operation, a filter for providing a monotonically varying differential path length as the focal spot moves relative to the filter in at least one dimension, a detector having a plurality of detector channels, said x-ray source oriented so that the x-rays from said x-ray source impinge upon said detector during operation, and an x-ray beam position detection system coupled to said detector, said x-ray beam position detection system comprising a processor programmed to:
- for respective selected detector channels, sum the signal intensities detected at each selected detector channel over an entire scan to generate a summed intensity signal for each selected channel, at least two detector channels being selected for such summation;
- and
- determine a change in x-ray beam position using the summed intensity signals for at least two selected detector channels.
A method for operating a computed tomography system, the computed tomography system including an x-ray source having a focal spot during operation, a filter for providing a monotonically varying differential path length as the focal spot moves relative to the filter in at least one dimension, and a detector having a plurality of detector channels, the x-ray source oriented so that the x-rays from the x-ray source impinge upon the detector during operation, said method comprising the steps of:
- for respective selected detector channels, summing the signal intensities detected at each selected detector channel over an entire scan to generate a summed intensity signal for each selected channel, at least two detector channels being selected for such summation;
- and
- determining a change in x-ray beam position using the summed intensity signals for at least two selected detector channels.
Dependencies are inferred from the claim text.