US5867553A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Computed tomography scanner with reduced power x-ray source
Assignee: Analogic Corp
•
Filing: 1996-10-30
•
Granted: 1999-02-02
•
Expires: 2016-10-30
Abstract
Abstract The disclosed CT scanner includes an X-ray source and an array of X-ray detectors fixed to a reduced geometry disk which is supported for rotation about an isocenter of the disk. The X-ray source is a reduced power source and a beam hardening filter of reduced size is positioned proximal to the X-ray source so the scanner uses a relatively soft X-ray beam. The scanner further includes circuitry for compensating for non-linearities and channel-to-channel variation in the X-ray detectors.
Inventors
- 👤 Bernard M. Gordon
- 👤 John Dobbs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:14
CPC Classifications
G; G01; G01N; G01N23/00; A; A61; A61B; A61B6/00; A61B6/40; A61B6/4064; A61B6/4071; A61B6/02; A61B6/03; A61B6/032; A61B6/4021; A61B6/4035; A61B6/58; A61B6/582; A61B6/583
Claims Analysis
Total Claims: 75
Claim 1
Independent Claim
159 words
A medical computed tomography scanning system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays so that the X-rays emanate substantially from a focal spot, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; a support for supporting a patient; and means for rotating at least the X-ray generating means about a rotation axis defining an isocenter of the system such that at least said X-ray generating means rotates about the support and the focal spot remains substantially at a fixed, predetermined radial distance from the isocenter during a scan; wherein the means for generating X-rays is positioned for rotation about said rotation axis such that the focal spot is separated a substantially fixed radial distance from the isocenter by a predetermined amount sufficient to accommodate a patient but less than about 510 mm.
Claim 2
Dependent Claim
159 words
A medical computed tomography scanning system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays so that the X-rays emanate substantially from a focal spot, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; a support for supporting a patient; and means for rotating at least the X-ray generating means about a rotation axis defining an isocenter of the system such that at least said X-ray generating means rotates about the support and the focal spot remains substantially at a fixed, predetermined radial distance from the isocenter during a scan; wherein the means for generating X-rays is positioned for rotation about said rotation axis such that the focal spot is separated a substantially fixed radial distance from the isocenter by a predetermined amount sufficient to accommodate a patient but less than about 510 mm.
Claim 3
Dependent Claim
33 words
A system according to claim 1, wherein the X-ray generating means includes a source of X-rays operable at a rated power of less than about 12 kW, but sufficient to perform a scan.
Claim 4
Dependent Claim
57 words
A system according to claim 1, wherein the X-ray generating means includes an anode and a cathode, means for maintaining the anode at a potential different from the cathode and means for generating a current between the cathode and the anode so that the rated power is sufficient to perform a scan, but less than 12 kW.
Claim 5
Dependent Claim
72 words
A system according to claim 1, wherein the X-ray generating means for generating X-rays includes a filter so as to pass soft X-rays so that the energy levels of soft X-rays emanating from the focal spot and incident on the X-ray detector means between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter, and less than unfiltered X-rays emanating from the focal spot.
Claim 6
Dependent Claim
53 words
A system according to claim 1, wherein the X-ray generating means for generating X-rays operates so that the X-rays emanating from the focal spot and incident on the detector means include X-ray photons having a range of energy levels, the range of energy levels having, a peak between 20 keV and 50 keV.
Claim 7
Dependent Claim
58 words
A system according to claim 1, further including a beam hardening filter disposed proximal to the X-ray generating means and between the X-ray generating means and the X-ray detector means, the beam hardening filter comprising a sheet of metal providing an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 8
Dependent Claim
18 words
A system according to claim 1, wherein the X-ray detector means comprises a plurality of solid state detectors.
Claim 9
Dependent Claim
85 words
A system according to claim 1, wherein said X-ray detector means comprises a plurality of detectors, said system further comprising beam defining means, mounted proximal to the focal spot, for forming a fan beam of the X-rays so that at least a portion of the fan beam is incident on the plurality of detectors, and monitoring means for maintaining the fan beam substantially incident on each of said detectors irrespective of any displacement of said focal spot in a direction parallel to the rotation axis.
Claim 10
Dependent Claim
66 words
A system according to claim 8, wherein said X-ray detector means comprises an array of detectors, and the monitoring means includes (a) means for sensing a displacement of the focal spot in a direction parallel to the rotation axis, and (b) means for shifting the beam defining means so as to maintain the fan beam substantially incident on the same portion of the array of detectors.
Claim 11
Dependent Claim
35 words
A system according to claim 1, wherein said X-ray detector means comprises a plurality of detectors, and further comprising best estimate filter means for filtering the output signals generated by the plurality of X-ray detectors.
Claim 12
Dependent Claim
35 words
A system according to claim 1, wherein said X-ray detector means comprises a plurality of detectors, and further comprising calibration means for compensating for a non-linearity of the signal output of each of the detectors.
Claim 13
Dependent Claim
28 words
A system according to claim 1, wherein said X-ray detector means comprises a plurality of detectors, and further comprising calibration means for compensating for variations among the detectors.
Claim 14
Dependent Claim
52 words
A system according to claim 1, wherein the means for generating X-rays is positioned for rotation about said rotation axis such that the focal spot is separated a substantially fixed radial distance from the isocenter by less than about 510 mm, but greater than a distance on the order of 450 mm.
Claim 15
Dependent Claim
39 words
A system according to claim 1, wherein the X-ray generating means includes a source of X-rays operable at a rated power of less than about 12 kW, but greater than a power level on the order of 1 kW.
Claim 16
Dependent Claim
30 words
A system according to claim 1, wherein the X-ray generating means includes a source of X-rays operable so that said source uses on the order of 100 mAs per scan.
Claim 17
Dependent Claim
115 words
A medical computed tomography system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; a support for supporting a patient; and means for rotating at least the X-ray generating means about a rotation axis such that said X-ray generating means rotates about said support; wherein the X-ray generating means includes a source of X-rays operable at a rated power less than 12 kW, but sufficient to perform a 360 degree scan in a time period on the order of two seconds.
Claim 18
Dependent Claim
115 words
A medical computed tomography system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; a support for supporting a patient; and means for rotating at least the X-ray generating means about a rotation axis such that said X-ray generating means rotates about said support; wherein the X-ray generating means includes a source of X-rays operable at a rated power less than 12 kW, but sufficient to perform a 360 degree scan in a time period on the order of two seconds.
Claim 19
Dependent Claim
14 words
A system according to claim 16, wherein the X-ray detectors comprise solid state detectors.
Claim 20
Dependent Claim
106 words
A system according to claim 16, wherein said X-ray generating means for generating X-rays generates the X-rays so that the X-rays emanate substantially from a focal spot and said X-ray detector means comprises a plurality of detectors, said system further comprising beam defining means, mounted proximal to the focal spot, for forming a fan beam of the X-rays so that at least a portion of the fan beam is incident on the plurality of detectors, and monitoring means for maintaining the fan beam substantially incident on each of said detectors irrespective of any displacement of said focal spot in a direction parallel to the rotation axis.
Claim 21
Dependent Claim
56 words
A system according to claim 18, wherein the monitoring means includes (a) means for sensing a displacement of the focal spot in a direction parallel to the rotation axis, and (b) means for shifting the beam defining means so as to maintain the fan beam substantially incident on the same portion of the array of detectors.
Claim 22
Dependent Claim
35 words
A system according to claim 16, wherein said X-ray detector means comprises a plurality of detectors, and further comprising best estimate filter means for filtering the output signals generated by the plurality of X-ray detectors.
Claim 23
Dependent Claim
35 words
A system according to claim 16, wherein said X-ray detector means comprises a plurality of detectors, and further comprising calibration means for compensating for a non-linearity of the signal output of each of the detectors.
Claim 24
Dependent Claim
28 words
A system according to claim 16, wherein said X-ray detector means comprises a plurality of detectors, and further comprising calibration means for compensating for variations among the detectors.
Claim 25
Dependent Claim
67 words
A system according to claim 16, wherein the X-ray generating means for generating X-rays operates so that the energy levels of soft X-ray photons generated by the X-ray generating means and incident on the X-ray detector means between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter, and less than unfiltered X-rays generated by the X-ray generating means.
Claim 26
Dependent Claim
44 words
A system according to claim 16, wherein the X-rays generated by the X-ray generating means and incident on the detector means include X-ray photons having a range of energy levels, the range of energy levels having a peak between 20 keV and 50 keV.
Claim 27
Dependent Claim
58 words
A system according to claim 16, further including a beam hardening filter disposed proximal to the X-ray generating means and between the X-ray generating means and the X-ray detector means, the beam hardening filter comprising a sheet of metal providing an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 28
Dependent Claim
151 words
A medical computed tomography system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; a support for supporting a patient; and means for rotating at least the X-ray generating means about a rotation axis such that said X-ray generating rotates about said support; wherein the X-ray generating means for generating X-rays includes a source of X-rays and a filter so as to pass soft X-rays so that the energy levels of soft X-ray photons generated by said X-ray generating means and incident on the X-ray detector means between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter and less than unfiltered X-rays generated by said source of X-rays.
Claim 29
Dependent Claim
151 words
A medical computed tomography system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; a support for supporting a patient; and means for rotating at least the X-ray generating means about a rotation axis such that said X-ray generating rotates about said support; wherein the X-ray generating means for generating X-rays includes a source of X-rays and a filter so as to pass soft X-rays so that the energy levels of soft X-ray photons generated by said X-ray generating means and incident on the X-ray detector means between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter and less than unfiltered X-rays generated by said source of X-rays.
Claim 30
Dependent Claim
55 words
A system according to claim 26, wherein the X-ray generating means for generating X-rays operates so that X-ray photons generated by said X-ray generating means and incident on the X-ray detector means include X-ray photons having a range of energy levels, the range of energy levels having a peak between 20 keV and 50 keV.
Claim 31
Dependent Claim
58 words
A system according to claim 26, further including a beam hardening filter disposed proximal to the X-ray generating means and between the X-ray generating means and the X-ray detector means, the beam hardening filter comprising a sheet of metal providing an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 32
Dependent Claim
118 words
A medical computed tomography system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; means for rotating at least the X-ray generating means about a rotation axis; a support for supporting a patient; and a beam hardening filter disposed proximal to the X-ray generating means and between the X-ray generating means and the X-ray detector means, the beam hardening filter comprising a sheet of metal providing an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 33
Dependent Claim
118 words
A medical computed tomography system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; means for rotating at least the X-ray generating means about a rotation axis; a support for supporting a patient; and a beam hardening filter disposed proximal to the X-ray generating means and between the X-ray generating means and the X-ray detector means, the beam hardening filter comprising a sheet of metal providing an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 34
Dependent Claim
18 words
A system according to claim 29, wherein the X-ray detector means includes a plurality of solid state detectors.
Claim 35
Dependent Claim
106 words
A system according to claim 29, wherein said X-ray generating means for generating X-rays generates the X-rays so that the X-rays emanate substantially from a focal spot and said X-ray detector means comprises a plurality of detectors, said system further comprising beam defining means, mounted proximal to the focal spot, for forming a fan beam of the X-rays so that at least a portion of the fan beam is incident on the plurality of detectors, and monitoring means for maintaining the fan beam substantially incident on each of said detectors irrespective of any displacement of said focal spot in a direction parallel to the rotation axis.
Claim 36
Dependent Claim
56 words
A system according to claim 31, wherein the monitoring means includes (a) means for sensing a displacement of the focal spot in a direction parallel to the rotation axis, and (b) means for shifting the beam defining means so as to maintain the fan beam substantially incident on the same portion of the array of detectors.
Claim 37
Dependent Claim
28 words
A system according to claim 29, wherein said X-ray detector means comprises a plurality of detectors, and further comprising calibration means for compensating for variations among the detectors.
Claim 38
Dependent Claim
35 words
A system according to claim 29, wherein said X-ray detector means comprises a plurality of detectors, and further comprising calibration means for compensating for a non-linearity of the signal output of each of the detectors.
Claim 39
Dependent Claim
35 words
A system according to claim 29, wherein said X-ray detector means comprises a plurality of detectors, and further comprising best estimate filter means for filtering the output signals generated by the plurality of X-ray detectors.
Claim 40
Dependent Claim
97 words
A medical computed tomography system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; a support for supporting a patient; and means for rotating at least the X-ray generating means about a rotation axis such that said X-ray generating means rotates about said support; wherein the X-ray generating means includes a source of X-rays operable on the order of 100 mAs per scan.
Claim 41
Dependent Claim
97 words
A medical computed tomography system, comprising: X-ray tomography means including (a) X-ray generating means for generating X-rays, and (b) X-ray detector means for detecting at least a portion of the X-rays generated by the X-ray generating means and incident on the X-ray detection means during a tomographic scan; a support for supporting a patient; and means for rotating at least the X-ray generating means about a rotation axis such that said X-ray generating means rotates about said support; wherein the X-ray generating means includes a source of X-rays operable on the order of 100 mAs per scan.
Claim 42
Dependent Claim
67 words
A system according to claim 36, wherein the X-ray generating means for generating X-rays operates so that the energy levels of soft X-ray photons generated by the X-ray generating means and incident on the X-ray detector means between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter and less than unfiltered X-rays generated by the X-ray generating means.
Claim 43
Dependent Claim
44 words
A system according to claim 36, wherein the X-rays generated by the X-ray generating means and incident on the detector means include X-ray photons having a range of energy levels, the range of energy levels having a peak between 20 keV and 50 keV.
Claim 44
Independent Claim
52 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and during a scan, rotating an X-ray source about a rotation axis such that said X-ray source rotates about the patient and operating the X-ray source at a rate on the on the order of 100 mAs per scan.
Claim 45
Independent Claim
52 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and during a scan, rotating an X-ray source about a rotation axis such that said X-ray source rotates about the patient and operating the X-ray source at a rate on the on the order of 100 mAs per scan.
Claim 46
Dependent Claim
70 words
A method according to claim 39, wherein the step of operating the X-ray source includes the step of generating X-rays so that the energy levels of soft X-ray photons generated by the X-ray source and incident on an array of detectors between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter and less than unfiltered X-rays generated by the X-ray source.
Claim 47
Dependent Claim
41 words
A method according to claim 39, wherein the step of operating the X-ray source includes the step of generating X-ray photons having a range of energy levels, the range of energy levels having a peak between 20 keV and 50 keV.
Claim 48
Independent Claim
94 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and rotating at least an X-ray source having a focal spot about a rotation axis so as to define an isocenter such that (a) at least the X-ray source rotates about the patient and the focal spot remains substantially at a fixed, predetermined radial distance from the isocenter during a scan, and (b) the focal spot is separated a substantially fixed radial distance from the isocenter by a predetermined amount sufficient to accommodate a patient, but less than about 510 mm.
Claim 49
Independent Claim
94 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and rotating at least an X-ray source having a focal spot about a rotation axis so as to define an isocenter such that (a) at least the X-ray source rotates about the patient and the focal spot remains substantially at a fixed, predetermined radial distance from the isocenter during a scan, and (b) the focal spot is separated a substantially fixed radial distance from the isocenter by a predetermined amount sufficient to accommodate a patient, but less than about 510 mm.
Claim 50
Dependent Claim
31 words
A method according to claim 42, further including the step of operating the X-ray source at a rated power of less than about 12 kW, but sufficient to perform a scan.
Claim 51
Dependent Claim
57 words
A method according to claim 42, wherein the X-ray source includes an anode and a cathode, further including the steps of maintaining the anode at a potential different from the cathode; and generating a current between the cathode and the anode so that the rated power is sufficient to perform a scan, but less than 12 kW.
Claim 52
Dependent Claim
69 words
A method according to claim 42, wherein the X-ray source includes a filter so as to pass soft X-rays so that the energy levels of soft X-rays emanating from the focal spot and incident on an array of X-ray detectors between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter, and less than unfiltered X-rays emanating from the focal spot.
Claim 53
Dependent Claim
42 words
A method according to claim 42, wherein the X-rays emanating from the focal spot and incident on the detectors include X-ray photons having a range of energy levels, the range of energy levels having a peak between 20 keV and 50 keV.
Claim 54
Dependent Claim
60 words
A method according to claim 42, further including the step of disposing a beam hardening filter proximal to the X-ray source and between the X-ray source and an array of X-ray detectors, the beam hardening filter comprising a sheet of metal providing an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 55
Dependent Claim
76 words
A method according to claim 42, further comprising the steps of forming a fan beam of the X-rays so that at least a portion of the fan beam is incident on an array of detectors, and monitor the position of the fan beam relative to the rotation axis for maintaining the fan beam substantially incident on each of the detectors irrespective of any displacement of the focal spot in a direction parallel to the rotation axis.
Claim 56
Dependent Claim
53 words
A method according to claim 48, wherein the step of monitoring includes (a) sensing a displacement of the focal spot in a direction parallel to the rotation axis, and (b) shifting a beam defining subsystem so as to maintain the fan beam substantially incident on the same portion of the array of detectors.
Claim 57
Dependent Claim
29 words
A method according to claim 42, further comprising the step of filtering each of the output signals generated by the plurality of X-ray detectors with a best estimate filter.
Claim 58
Dependent Claim
24 words
A method according to claim 42, further comprising the step of compensating for a non-linearity of the signal output of each of the detectors.
Claim 59
Dependent Claim
31 words
A method according to claim 42, further comprising the step of compensating for variations in responses of detectors of an array of detectors positioned to receive X-rays from the X-ray source.
Claim 60
Independent Claim
55 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and scanning the patient with an X-ray beam while filter the X-ray beam with a beam hardening filter comprising a sheet of metal providing an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 61
Independent Claim
55 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and scanning the patient with an X-ray beam while filter the X-ray beam with a beam hardening filter comprising a sheet of metal providing an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 62
Independent Claim
87 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and rotating the X-ray source about a rotation axis such that the X-ray source rotates about the patient, and generates soft X-rays so that the energy levels of soft X-ray photons generated by said X-ray source and incident on an array of X-ray detectors between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter and less than unfiltered X-rays generated by said source of X-rays.
Claim 63
Independent Claim
87 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and rotating the X-ray source about a rotation axis such that the X-ray source rotates about the patient, and generates soft X-rays so that the energy levels of soft X-ray photons generated by said X-ray source and incident on an array of X-ray detectors between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter and less than unfiltered X-rays generated by said source of X-rays.
Claim 64
Dependent Claim
44 words
A method according to claim 54, the soft X-rays generated by the X-ray source and incident on the X-ray detector means include X-ray photons having a range of energy levels, the range of energy levels having a peak between 20 keV and 50 keV.
Claim 65
Dependent Claim
43 words
A method according to claim 54, further including the step of filtering the X-rays with a beam hardening filter, wherein the beam hardening filter provides an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 66
Independent Claim
65 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and rotating at least the X-ray source about a rotation axis such that the X-ray source rotates about the patient and the X-ray source is operated at a rated power less than 12 kW, but sufficient to perform a 360 degree scan in a time period on the order of two seconds.
Claim 67
Independent Claim
65 words
A method of performing a medical computed tomography scan, comprising: supporting a patient; and rotating at least the X-ray source about a rotation axis such that the X-ray source rotates about the patient and the X-ray source is operated at a rated power less than 12 kW, but sufficient to perform a 360 degree scan in a time period on the order of two seconds.
Claim 68
Dependent Claim
63 words
A method according to claim 57, wherein the X-ray source is operated so that the energy levels of soft X-ray photons generated by the X-ray source and incident on an array of X-ray detectors between about 20 keV and about 50 keV are greater than that provided by a 0.008 inch copper filter, and less than unfiltered X-rays generated by the X-ray source.
Claim 69
Dependent Claim
44 words
A method according to claim 57, wherein the X-rays generated by the X-ray source and incident on an array of detectors includes X-ray photons having a range of energy levels, the range of energy levels having a peak between 20 keV and 50 keV.
Claim 70
Dependent Claim
57 words
A method according to claim 57, further including the step of positioning proximal to the X-ray generating means and between the X-ray source and an array of X-ray detectors, a beam hardening filter comprising a sheet of metal providing an X-ray photon filtering characteristic equivalent to that of a sheet of copper less than 0.008 inches thick.
Claim 71
Dependent Claim
86 words
A method according to claim 57, wherein the X-ray source generates X-rays so that the X-rays emanate substantially from a focal spot, said method further comprising the step of forming a fan beam of the X-rays emanating from the focal spot so that at least a portion of the fan beam is incident on a plurality of detectors, and maintaining the fan beam substantially incident on each of the detectors irrespective of any displacement of the focal spot in a direction parallel to the rotation axis.
Claim 72
Dependent Claim
60 words
A method according to claim 61, wherein the step of maintaining the fan beam substantially incident includes the steps of (a) sensing a displacement of the focal spot in a direction parallel to the rotation axis, and (b) shifting the fan beam so as to maintain the fan beam substantially incident on the same portion of the plurality of detectors.
Claim 73
Dependent Claim
47 words
A method according to claim 57, wherein a plurality of X-ray detectors are positioned to receive X-rays emanating from the X-ray source during a scan, further including the step of filtering each of the output signals of the X-ray detectors with a plurality of best estimate filters.
Claim 74
Dependent Claim
24 words
A method according to claim 63, further including the step of compensating for a non-linearity of the signal output of each of the detectors.
Claim 75
Dependent Claim
20 words
A method according to claim 63, further including the step of compensating for variations in the responses of the detectors.
References Cited (Backward Citations)
US4365155A
Cited
US4547893A
Cited
US4785354A
Cited
US4803711A
Cited
US4911189A
Cited
US5220589A
Cited
US5550886A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-02-01 | 2002-08-03 | 2003-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-02-01 | 2006-08-03 | 2007-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-02-01 | 2010-08-03 | 2011-02-02 | $7700.00 | Window Closed / Lapsed |