Systems and methods for focal spot motion detection and correction
AssigneeGeneral Electric Company
InventorsBiju Jacob, Mingye Wu, Mark Allen Adamak
Life of this patent
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Abstract
The techniques disclosed may be used to detect and correct channel gain errors resulting from X-ray focal spot mis-alignment during the course of a scan. One benefit of the present invention relative to conventional techniques is that additional hardware is not required for detection of focal spot drift. Instead, the static mis-alignment of each blade is taken into account as part of estimating and correcting X-ray focal spot drift or mis-alignment. In this manner, the risk of image artefacts due to focal spot motion is reduced and the need for costly hardware solutions to detect focal spot motion is avoided.
Claims21
A method for estimating motion of an X-ray focal spot, comprising the acts of:
- acquiring image data by emitting X-rays from the X-ray focal spot toward a radiation detector comprising a plurality of channels, wherein a first subset of the channels each have a collimator blade positioned above the respective channel and a second subset of channels are unobstructed by collimator blades;
- for at least one respective channel of the first subset:
- estimating a relative channel gain for the respective channel;
- and
- estimating X-ray focal spot motion using the relative channel gain and an X-ray focal spot motion sensitivity ratio for the respective channel.
An imaging system, comprising:
- a source of X-ray radiation configured to emit X-rays from a focal spot during operation;
- a collimator comprising a plurality of collimator blades;
- a radiation detector, comprising a plurality of pixels, each pixel corresponding to a channel of the radiation detector, wherein a first subset of the channels each have a collimator blade positioned above the respective channel and a second subset of channels are unobstructed by collimator blades;
- processing circuitry configured to perform acts comprising:
- acquiring image data by causing X-rays to be emitted from the X-ray source toward the radiation detector;
- for at least one respective channel of the first subset:
- estimating a relative channel gain for the respective channel;
- and
- estimating X-ray focal spot motion using the relative channel gain and an X-ray focal spot motion sensitivity ratio for the respective channel.
A method for correcting for focal spot motion, comprising the acts of:
- estimating a relative channel gain for a respective channel of a radiation detector;
- estimating motion of an X-ray focal spot using the relative channel gain and an X-ray focal spot motion sensitivity ratio for the respective channel;
- calculating a focal spot motion correction based on the estimate of motion of the X-ray focal spot;
- and
- using the focal spot motion correction factor as part of an image reconstruction or post-reconstruction process to correct or remove artifacts or other image irregularities.
Dependencies are inferred from the claim text.