Truncation compensation algorithm for iterative reconstruction
AssigneeKoninklijke Philips Electronics N.V.
InventorsJinghan Ye, Mary K. Durbin
Life of this patent
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Abstract
An imaging system (10) includes at least one radiation detector (20) disposed adjacent a subject receiving aperture (18) to detect and measure at least one of emission and transmission radiation from a subject, the detector (20) at a plurality of projection angles. A processor (64) determines which radiation data belong to a field of view of the radiation detector (20) at each projection angle. An image processor (70, 72) iteratively reconstructs the radiation detected only in the determined field of view into image representations. Truncated data is compensated by supplying the untruncated data from the projections taken at different angles at which the truncated data is untruncated.
Claims20
An imaging system comprising:
- at least one radiation detector disposed adjacent a subject to detect and measure at least one of emission and transmission radiation from a subject, the detector being movable around the subject to receive the radiation and generate measured projection data at a plurality of projection angles;
- a FOV means for determining a plurality of pixels which belongs to a field of view of the radiation detector at each projection angle;
- an image processor which iteratively reconstructs the radiation detected only in the field of view into image representations, the image processor including:
- a forward projector which projects the image representations from the corresponding image memory;
- a means for comparing the forward projected image representations with the measured projection data and, based on the comparison, determining a set of correction factors;
- and
- a backprojector for backprojecting the correction factors, which correspond only to the pixels within the determined field of view, into the image representations;
- and
- an image memory in which the image representations are iteratively reconstructed.
A method of imaging comprising:
- detecting and measuring at least one of emission and transmission radiation from a subject at a plurality of projection angles;
- generating measured projection data at the plurality of projection angles;
- determining a plurality of pixels which belongs to a field of view within which the radiation is detected by a radiation detector at each projection angle;
- and
- iteratively reconstructing the radiation detected in the field of view into image representations in an image memory, including:
- forward projecting the image representations;
- comparing the forward projected image representations with the measured projection data;
- based on the comparison, determining a set of correction factors;
- and
- backprojecting the correction factors, which correspond only to the pixels within the determined field of view, into the image representations.
A diagnostic imaging system including:
- an emission memory which stores measured emission projections from a subject which projections are detected by a radiation detector;
- a transmission memory which stores measured transmission data from the subject which data are detected by the radiation detector;
- a processor which determines a field of view of the radiation detector;
- an attenuation map memory which stores transmission attenuation maps;
- an image memory which stores emission maps;
- a processor which is programmed to perform steps of:
- (a) generating the transmission attenuation maps via forward projecting the transmission attenuation maps from the attenuation map memory,
- (b) comparing the projected transmission attenuation maps with the transmission data,
- (c) based on the comparison, determining a set of correction factors,
- (d) backprojecting the correction factors, which correspond only to the data within the determined field of view, into the transmission attenuation maps of the attenuation map memory;
- and
- (e) iteratively repeating steps (a) through (d) until the projected transmission attenuation maps converge with the transmission data.
Dependencies are inferred from the claim text.