EP0714038A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Digital sensor cassette for mammography
Assignee: Lockheed Martin Corp
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Filing: 1995-11-24
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Granted: —
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Expires: 2015-11-24
Abstract
Abstract A CCD-scintillator x-ray image sensor (18) has a high sensitivity at room temperature and a low profile, enabling the use of the x-ray image sensor in most modern mammography x-ray machines. A cassette 10 that encloses the CCD-based x-ray image sensor has the approximate dimensions of 10.5 x 7.7 x 0.6 inches, and is thus form and fit compatible with conventional film-based cassettes. An electronic interface to the cassette requires but a single cable (24) and a standard connector (22) for connection to a CCD sensor electronics unit. The CCD sensor electronics unit interfaces to a computer, such as a conventional personal computer or workstation, having a relatively high resolution display and a provision for digitally recording high-resolution electronic images. The high sensitivity at ambient (room) temperature results from an x-ray scintillator screen (18c) that is coupled to the CCD image sensor (18a) via a bias cut fiber optic faceplate (18b). The CCD image sensor has very low dark current density, high responsivity to the green fluorescence of the screen, and multiple output ports for minimizing the time required for readout and for minimizing the noise bandwidth at the output.
Inventors
- 👤 Michael Sayag
- 👤 Andrew Karellas
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 08:23
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/50; A61B6/502; A61B6/42; A61B6/4208; A61B6/4233; G; G01; G01T; G01T1/00; G01T1/29; G01T1/2914; G01T1/2921; G01T1/2928
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
87 words
An imaging device, comprising: a region comprised of a material that is responsive to incident x-ray radiation for converting at least a portion of the incident x-ray radiation into light; a two dimensional light sensor array having a radiation receiving surface containing charge coupled device light sensors; and a bias cut fiber optic faceplate interposed between a bottom surface of the region and said radiation receiving surface of the array for guiding the light to the charge coupled device light sensors with a substantially 1:1 imaging ratio.
Claim 2
Dependent Claim
34 words
An imaging device as set forth in claim 1 wherein said device has a total thickness that enables said device to be installed within a housing having a total thickness of approximately 0.6 inch.
Claim 3
Dependent Claim
26 words
An imaging device as set forth in claim 2 wherein said housing is has at least one wall that is substantially transparent to the incident x-rays.
Claim 4
Dependent Claim
89 words
An imaging device as set forth in claim 1 wherein said device is installed within a housing that also contains a plurality of preamplifiers for reading out a light-induced charge from individual ones of said charge coupled device light sensors, said housing further containing a plurality of A/D converters for converting electrical signals representative of the read-out light induced charge to digital representations of the electrical signals and means for coupling outputs of said A/D converters to a cable for conveying said outputs to a remotely located data processor.
Claim 5
Dependent Claim
41 words
An imaging device as set forth in claim 4 wherein said housing has dimensions that are form and fit compatible with an x-ray film cassette of a type that is installable within an x-ray machine for use during a mammographic examination.
Claim 6
Dependent Claim
274 words
An x-ray system including an x-ray source providing an x-ray beam, said x-ray system further comprising: x-ray sensor means for generating a signal for indicating a presence of said x-ray beam; and an electronic imaging cassette installable within said x-ray beam, said cassette having at least one wall that is substantially transparent to said x-ray beam, said cassette containing at least one imaging device comprising; scintillating screen means comprised of a material that is responsive to said x-ray beam that passes through said wall for converting at least a portion of the beam into light; a two dimensional light sensor array having a radiation receiving surface containing charge coupled device light sensors; and a bias cut fiber optic faceplate interposed between a bottom surface of the screen means and said radiation receiving surface of said array for guiding the light to the charge coupled device light sensors; said cassette further comprising, a plurality of amplifier circuits for converting a light-induced charge from individual ones of said charge coupled device light sensors into representative voltages; a plurality of A/D converters for converting the voltages representative of the read-out light induced charge into digital representations of the voltages; means for coupling outputs of said A/D converters to a remotely located image display means; and timing circuit means operable for generating timing signals for said array for controlling the read out of the light-induced charge from individual ones of said charge coupled device light sensors, said timing circuit means being responsive to said signal generated by said x-ray sensor means for suspending the generation of said timing signals during a time that said x-ray beam is present.
Claim 7
Dependent Claim
35 words
An x-ray system as set forth in claim 6 wherein said image display means includes means for transforming the outputs of said A/D converters to displayable image pixels and for storing said displayable image pixels.
Claim 8
Dependent Claim
62 words
An x-ray system as set forth in claim 6 wherein said scintillating screen means has a surface area suitable for obtaining a radiographic image of at least a portion of a breast, and wherein said bias cut fiber optic faceplate relays light generated by said scintillating screen means to said radiation receiving surface of said array with a substantially 1:1 imaging ratio.
Claim 9
Independent Claim
171 words
A method of obtaining an x-ray of an object, comprising the steps of: providing an electronic cassette containing an uncooled two dimensional CCD array having a radiation receiving surface that is optically coupled to an output of a material that is responsive to x-ray radiation that passes through the object for converting the x-ray radiation into electromagnetic radiation having wavelengths that are suitable for conversion into photo-induced charge by individual pixels of the CCD array; generating clocking pulses for reading out dark current charge from within individual pixels of the CCD array; generating a signal for indicating a beginning of an x-ray exposure of the object; in response to the generation of the signal, terminating the generation of the clocking pulses during the x-ray exposure so as to enable the accumulation of photo-induced charge within individual pixels of the CCD array; in response to a termination of the x-ray exposure, initiating the generation of the clocking pulses; and reading out the photo-induced charge from within individual pixels of the CCD array.
Claim 10
Dependent Claim
40 words
A method as set forth in claim 9 wherein the CCD array is partitioned into a plurality of sub-arrays, and wherein the step of reading out the photo-induced charge reads out the charge in parallel from each of the sub-arrays.
Claim 11
Dependent Claim
49 words
A method as set forth in claim 9 and further including the steps of: converting within the cassette the read out photo-induced charge from each pixel to a digital representation of the magnitude of the charge; and transmitting the digital representations from the cassette to a digital storage device.
Claim 12
Dependent Claim
59 words
A method as set forth in claim 9 and further including the steps of: converting within the cassette the read out photo-induced charge from each pixel to a digital representation of the magnitude of the charge; and transmitting the digital representations from the cassette to a display device for displaying an image corresponding to the read out photo-induced charge.
Claim 13
Independent Claim
183 words
A system for obtaining an x-ray of an object, comprising: an electronic cassette containing at least one uncooled two dimensional CCD array having a radiation receiving surface that is optically coupled to an output of a material that is responsive to x-ray radiation that passes through the object for converting the x-ray radiation into electromagnetic radiation having wavelengths that are suitable for conversion into photo-induced charge by individual pixels of the CCD array; means for outputting a signal for indicating a beginning of an x-ray exposure of the object; and means for generating clocking pulses for reading out dark current charge from within individual pixels of the CCD array, said generating means being responsive to the outputting of the signal for terminating the generation of the clocking pulses during the x-ray exposure so as to enable the accumulation of photo-induced charge within individual pixels of the CCD array, said generating means being further responsive to a termination of the x-ray exposure for initiating the generation of the clocking pulses for reading out the photo-induced charge from within individual pixels of the CCD array.
Claim 14
Dependent Claim
34 words
A system as set forth in claim 13 wherein the CCD array is partitioned into a plurality of sub-arrays, and wherein the photo-induced charge is read out in parallel from each of the sub-arrays.
Claim 15
Dependent Claim
52 words
A system as set forth in claim 13 and further comprising: means for converting, within the electronic cassette, the read out photo-induced charge from each pixel to a digital representation of the magnitude of the charge; and means for transmitting the digital representations from the electronic cassette to a digital storage device.
Claim 16
Dependent Claim
62 words
A system as set forth in claim 13 and further comprising: means for converting, within the electronic cassette, the read out photo-induced charge from each pixel to a digital representation of the magnitude of the charge; and means for transmitting the digital representations from the electronic cassette to a display device for displaying an image corresponding to the read out photo-induced charge.
Claim 17
Dependent Claim
43 words
A system as set forth in claim 13 and further comprising a bias cut fiber optic faceplate that is interposed between said material and said radiation receiving surface of said CCD array for guiding the light thereto with a substantially 1:1 imaging ratio.
Claim 18
Dependent Claim
43 words
A system as set forth in claim 13 wherein there are a plurality of said uncooled two dimensional CCD arrays that are closely abutted one to another for forming a substantially continuous image corresponding to an x-ray radiation transmission profile of the object.
References Cited (Backward Citations)
No citation records indexed.
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