Method and apparatus for optimizing dosage to scan subject
AssigneeGE Medical Systems Global Technology Company, LLC
InventorJiang Hsieh
Life of this patent
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Abstract
The present invention is directed to a CT imaging system utilizing a pre-subject cone-angle dependent filter to optimize dosage applied to the scan subject for data acquisition. The cone angle dependent pre-subject filter is designed to have a shape that is thicker for outer detector rows and thinner for inner detector rows. As a result, x-rays corresponding to the outer detector rows undergo greater filtering than the x-rays corresponding to the inner detector rows.
Claims23
A cone angle dependent pre-subject filter configuration for use with a radiation emitting imaging device, the filter configuration comprising:
- a flat surface configured to extend along a z-direction;
- a concave surface configured to extend parallel to the flat surface along the z-direction and arranged to optimize data utilization efficiency of the radiation emitting device;
- and
- a number of sidewalls oriented along an x-direction and connecting the flat surface and the concave surface in a single structure.
A radiation emitting imaging device comprising:
- a rotatable gantry having an opening defined therein for receiving a subject to be scanned;
- a subject positioner configured to position the subject within the opening along a z-axis;
- a high frequency (HF) electromagnetic energy projection source configured to project HF electromagnetic energy to the subject;
- at least one filtering device configured to filter HF electromagnetic energy projected to the subject, the filtering device having a body defined by a length that extends along the z-axis and a width that extends along an x-axis and when the body has a section of concavity that extends along the length of the filtering device;
- a detector array having a plurality of detectors to detect HF electromagnetic energy passing through the subject and to output a plurality of electrical signals indicative of an intensity of the HF electromagnetic energy detected;
- a data acquisition system (DAS) connected to the detector array and configured to receive the plurality of electrical signals;
- and
- an image reconstructor connected to the DAS and configured to reconstruct an image of the subject from the plurality of signals received by the DAS according to a reconstruction algorithm.
A cone angle dependent pre-subject filter comprising:
- means for increasing HF electromagnetic energy flux in a first region corresponding to a first set of rows of a CT detector array;
- means for decreasing HF electromagnetic energy flux in a second region corresponding to a second set of rows of the CT detector array.
A method of manufacturing a pre-subject filter for use with a radiation emitting imaging device, the method comprising the steps of:
- determining a desired noise index level and selecting a filtering material from a bulk having a requisite attenuation coefficient to achieve the desired noise index level;
- defining a block of filtering material;
- shaping the block to have a linear emission surface;
- and
- fashioning the block to have a curvilinear reception surface.
Dependencies are inferred from the claim text.