US4404591A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Slit radiography
Assignee: Philips North America LLC
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Filing: 1982-01-04
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Granted: 1983-09-13
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Expires: 2002-01-04
Abstract
Abstract In radiography apparatus a moving slit collimator is disposed between an X-ray source and a patient undergoing examination. Radiation is detected with an X-ray image intensifier and television pickup chain. The field of view of the television pickup is limited to that area of the output screen of the X-ray image intensifier which corresponds to the image produced by direct radiation which passes through the moving slit. The view of the television pickup may be limited by a second slit, disposed between the X-ray image intensifier and television pickup which moves in synchronism with the first slit. Alternately, the view of a television pickup may be limited by synchronizing scan signals for the pickup of the with the motion of the slit collimator.
Inventors
- 👤 David C. Bonar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 08:44
CPC Classifications
G; G21; G21K; G21K1/00; G21K1/02; G21K1/025; H; H05; H05G; H05G1/00; H05G1/08; H05G1/64
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
186 words
In a radiography system which includes: source means which function to direct X-ray radiation through an examination area; an X-ray image intensifier having an input screen which is disposed to receive radiation from the source means which has passed through the examination area and an output screen for producing an intensifed visible image which corresponds to radiation impinging on the input screen; television pickup means disposed to view the output screen which function to produce a television signal corresponding to an image thereon; and first scanning means which define and move a first X-ray collimator slit disposed between the source means and the examination area and which functions to limit direct radiation from the source means to a limited portion of the input screen; the improvement comprising second scanning means which function, in synchronism with the motion of the first collimator slit, to limit the view of the television pickup means to a limited area of the output screen on which the image corresponds to radiation on the limited area of the input screen which receives direct radiation from the source means through the first slit.
Claim 2
Dependent Claim
186 words
In a radiography system which includes: source means which function to direct X-ray radiation through an examination area; an X-ray image intensifier having an input screen which is disposed to receive radiation from the source means which has passed through the examination area and an output screen for producing an intensifed visible image which corresponds to radiation impinging on the input screen; television pickup means disposed to view the output screen which function to produce a television signal corresponding to an image thereon; and first scanning means which define and move a first X-ray collimator slit disposed between the source means and the examination area and which functions to limit direct radiation from the source means to a limited portion of the input screen; the improvement comprising second scanning means which function, in synchronism with the motion of the first collimator slit, to limit the view of the television pickup means to a limited area of the output screen on which the image corresponds to radiation on the limited area of the input screen which receives direct radiation from the source means through the first slit.
Claim 3
Dependent Claim
55 words
The apparatus of claim 1, wherein: the second scanning means comprises a second diaphragm which defines a second light collimator slit disposed between the output screen and the television pickup means and means for moving the second diaphragm so that the second slit is functionally aligned with and moves in synchronism with the first slit.
Claim 4
Dependent Claim
56 words
The apparatus of claim 1 or 2, further comprising means for scanning an image sensitive area of the television pickup means to produce a signal therefrom and wherein the second scanning means functions to limit the scan of the image sensitive area to limited portions thereof which view the said limited area of the output screen.
Claim 5
Dependent Claim
43 words
The apparatus of claim 3, wherein the means for scanning the image sensitive area further function to discharge background image information from the limited portions of the image sensitive area before producing a signal which corresponds to an image produced by direct radiation.
Claim 6
Dependent Claim
14 words
The apparatus of claim 4, wherein the television pickup means is a vidicon tube.
Claim 7
Dependent Claim
15 words
The apparatus of claim 3 where the television pickup means is a solid state array.
Claim 8
Dependent Claim
32 words
The apparatus of claim 2 wherein the first and second slits are rectangular and wherein the first and second scanning means move the slits perpendicular to the longitudinal dimension of the slits.
Claim 9
Dependent Claim
40 words
The apparatus of claim 2 wherein the first and second slits are sectors of circles disposed on a common axis and wherein the first and second scanning means function to rotate the first and second slits around the common axis.
Claim 10
Dependent Claim
23 words
The apparatus of claim 8 wherein the common axis is within a field of view of the input screen of the image intensifier.
Claim 11
Dependent Claim
57 words
The apparatus of claim 1 or 2 further comprising third diaphragm means which define a third collimator slit disposed between the examination area and the input screen of the X-ray image intensifier means and means for moving the third diaphragm means so that the third slit is aligned with and moves in synchronism with the first slit.
Claim 12
Independent Claim
51 words
The apparatus of claims 1 or 2 further comprising fourth diaphragm means which define a fourth collimator slit disposed between the source means and the first slit and means for moving the fourth diaphragm means so that the fourth slit is aligned with and moves in synchronism with the first slit.
Claim 13
Dependent Claim
49 words
The apparatus of claim 10 further comprising fourth diaphragm means which define a fourth collimator slit disposed between the source means and the first slit and means for moving the fourth diaphragm means so that the fourth slit is aligned with and moves in synchronism with the first slit.
Claim 14
Dependent Claim
69 words
The apparatus of claim 3 wherein the first slit is rectangular, the first scanning means moves the first diaphragm perpendicular to the longitudinal dimension of the first slit and wherein the means for scanning produces a raster scan having a horizontal sweep which is functionally parallel to the longitudinal dimension of the first slit and a vertical sweep which is functionally parallel to the motion of the first slit.
Claim 15
Dependent Claim
175 words
In the method of slit radiography which includes the steps of: directing X-ray radiation from an X-ray source, through an examination area and onto an input screen of an X-ray image intensifier; operating the image intensifier to produce, on an output screen thereof, a visible image of the X-rays which are incident on the input screen; viewing the output screen with a television pickup and scanning the pickup to produce a video signal which corresponds to the visible image; collimating the X-ray radiation through x-ray collimator slit which is disposed between the source and the examination area to limit direct X-ray illumination of the input screen to a small portion thereof; and moving the X-ray collimator slit to progressively scan the examination area and to progressively illuminate adjacent portions of the input screen with X-ray radiation; the improvement comprising: limiting the field of view of the television pickup to a small portion of the output screen on which the visible image corresponds to direct radiation which illuminates the input screen through the X-ray collimator slit.
Claim 16
Dependent Claim
175 words
In the method of slit radiography which includes the steps of: directing X-ray radiation from an X-ray source, through an examination area and onto an input screen of an X-ray image intensifier; operating the image intensifier to produce, on an output screen thereof, a visible image of the X-rays which are incident on the input screen; viewing the output screen with a television pickup and scanning the pickup to produce a video signal which corresponds to the visible image; collimating the X-ray radiation through x-ray collimator slit which is disposed between the source and the examination area to limit direct X-ray illumination of the input screen to a small portion thereof; and moving the X-ray collimator slit to progressively scan the examination area and to progressively illuminate adjacent portions of the input screen with X-ray radiation; the improvement comprising: limiting the field of view of the television pickup to a small portion of the output screen on which the visible image corresponds to direct radiation which illuminates the input screen through the X-ray collimator slit.
Claim 17
Dependent Claim
42 words
The method of claim 14 wherein the steps of limiting the field of view of the television pickup comprise moving an optical collimator slit between the output screen and the television pickup in synchronism with the motion of the X-ray collimator slit.
Claim 18
Dependent Claim
47 words
The method of claim 14 or 15 wherein the steps of limiting the field of view of the pickup comprises electrically scanning a limited portion of a light sensitive of the pickup in synchronism with the motion of the X-ray collimator slit to produce a viedo signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |