Exposure control in an x-ray image detector
First Claim
1. An X-ray detector apparatus comprising an array of detector pixels, each pixel comprising a conversion element for converting incident radiation into a charge flow, a charge storage element and a switching device enabling the charge stored to be provided to an output of the pixel, and wherein a plurality of dose sensing pixels further comprise a dose sensing element, wherein charge flow from the conversion element during X-ray exposure results in a change in the charge stored on the charge storage element and also results in a dose sensing signal being generated which can be read out from the pixel.
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Abstract
An X-ray detector apparatus comprises an array of detector pixels (20), each pixel (20) comprising a conversion element (26;260) for converting incident radiation into a charge flow, a charge storage element (28) and a switching device (29) enabling the charge stored to be provided to an output of the pixel (20). A plurality of dose sensing pixels further comprise a dose sensing element (40;50). Charge flow from the conversion element (26;260) during X-ray exposure results in a change in the charge stored on the charge storage element (28) and also results in a dose sensing signal being generated which can be read out from the pixel (20). The dose sensing pixels enable a dose signal to be obtained without reading the charges stored on the pixel charge storage elements, so that dose sensing can be carried out during exposure.
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Citations
15 Claims
- 1. An X-ray detector apparatus comprising an array of detector pixels, each pixel comprising a conversion element for converting incident radiation into a charge flow, a charge storage element and a switching device enabling the charge stored to be provided to an output of the pixel, and wherein a plurality of dose sensing pixels further comprise a dose sensing element, wherein charge flow from the conversion element during X-ray exposure results in a change in the charge stored on the charge storage element and also results in a dose sensing signal being generated which can be read out from the pixel.
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15. In an X-ray examination apparatus comprising:
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an X-ray source for exposing an object to be examined to X-ray energy and an X-ray detector for receiving an X-ray image after attenuation by the object to be examined, comprising an array of detector pixels, each pixel comprising a conversion element for converting incident radiation into a charge flow, a charge storage element and a switching device enabling the charge stored to be provided to an output of the pixel, wherein a plurality of dose sensing pixels further comprise a dose sensing element, wherein charge flow from the conversion element during X-ray exposure results in a change in the charge stored on the charge storage element and also results in a dose sensing signal being generated which can be read out from the pixel, a method of controlling the X-ray examination apparatus comprising;
exposing the object to be examined with X-ray radiation;
monitoring output signals from selected dose sensing pixels during the exposure;
halting the X-ray exposure in response to the dose sensing signal monitoring; and
reading out the charges stored on the charge storage elements to obtain an X-ray image.
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Specification