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US 7,583,790 B2Granted
Direct conversion energy discriminating CT detector with over-ranging correction
AssigneeGeneral Electric Company
InventorsDavid M. Hoffman, James Walter LeBlanc, John Eric Tkaczyk, Robert F. Senzig, Yanfeng Du
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Abstract
A CT detector capable of energy discrimination and direct conversion is disclosed. The detector includes multiple layers of semiconductor material with the layers having varying thicknesses. The detector is constructed to be segmented in the x-ray penetration direction so as to optimize count rate performance as well as avoid saturation. The detector also includes variable pixel pitch and a flexible binning of pixels to further enhance count rate performance.
Claims25
A CT detector comprising:
- a first pair of direct conversion layers arranged in an overlapping pattern and constructed to directly convert radiographic energy to electrical signals representative of energy sensitive radiographic data;
- and
- a first array of electrical contacts positioned between the first pair of direct conversion layers, each contact in the first array of electrical contacts electrically coupled to each of the first pair of direct conversion layers and configured to collect electrical signals converted in each of the first pair of direct conversion layers;
- wherein the first array of electrical contacts are electrically connected to form first and second sub-pixels, the first sub-pixel having an area greater than the second sub-pixel.
1 more element
A radiographic imaging system comprising:
- a radiation source to project radiographic energy toward a subject to be scanned;
- a detector assembly configured to receive radiographic energy from the radiation source and attenuated by the subject, the detector assembly comprising:
- a plurality of direct conversion detectors configured to convert the received radiographic energy to electrical signals representative of energy sensitive radiographic data, the plurality of direct conversion detectors including:
- a first direct conversion detector;
- and
- a second direct conversion detector positioned to receive radiographic energy passing through the first direct conversion detector;
- and
- a first set of electrical contacts positioned between and in contact with the first and second direct conversion detectors and configured to collect electrical signals from both the first and second direct conversion detectors;
- a data acquisition system (DAS) coupled to the first set of electrical contacts and configured to receive the electrical signals therefrom;
- and
- an image reconstructor connected to the DAS and configured to reconstruct an image of the subject from the electrical signals received by the DAS;
- wherein the first set of electrical contacts comprises two or more sub-pixels, each sub-pixel comprising one or more electrical contacts of the first set of electrical contacts.
9 more elements
A method of manufacturing a CT detector, the method comprising:
- positioning a first direct conversion layer to receive x-rays from an x-ray source;
- positioning a second direct conversion layer to receive x-rays from the x-ray source that pass through the first direct conversion layer;
- attaching a first array of electrical contacts to each of the first and second direct conversion layers;
- electrically coupling each contact in the first array of electrical contacts to each of the first and second direct conversion layers such that each contact is configured to collect electrical charge converted in each of the first and second direct conversion layers;
- and
- combining outputs of the first array of electrical contacts such that data from non-saturated electrical contacts is read out to a DAS, and data from saturated electrical contacts is ignored.
3 more elements
A CT detector comprising:
- a first direct conversion layer constructed to directly convert radiographic energy to electrical signals representative of energy sensitive radiographic data;
- a second direct conversion layer constructed to directly convert radiographic energy to electrical signals representative of energy sensitive radiographic data;
- an array of electrical contacts positioned between the first and second direct conversion layers, each contact in the array of electrical contacts electrically coupled to each of the first and second direct conversion layers and configured to collect electrical signals converted in each of the first and second direct conversion layers;
- and
- a truth circuit coupled to the array of electrical contacts, the truth circuit configured to group electrical signals of non-saturated channels and ignore electrical signals from saturated channels.
2 more elements
A CT detector comprising:
- a first direct conversion layer constructed to directly convert radiographic energy to electrical signals representative of energy sensitive radiographic data;
- a second direct conversion layer constructed to directly convert radiographic energy to electrical signals representative of energy sensitive radiographic data;
- an array of electrical contacts positioned between the first and second direct conversion layers, each contact in the array of electrical contacts electrically coupled to each of the first and second direct conversion layers and configured to collect electrical signals converted in each of the first and second direct conversion layers;
- and
- a circuit configured to receive signals from the array of electrical contacts, the circuit comprising an energy level discriminator configured to exclude signals deriving from photons having an energy level corresponding to a noise level.
2 more elements
Dependencies are inferred from the claim text.