CA1235531A - Rotating x-ray mask with sector slits - Google Patents
Rotating x-ray mask with sector slitsInfo
- Publication number
- CA1235531A CA1235531A CA000504552A CA504552A CA1235531A CA 1235531 A CA1235531 A CA 1235531A CA 000504552 A CA000504552 A CA 000504552A CA 504552 A CA504552 A CA 504552A CA 1235531 A CA1235531 A CA 1235531A
- Authority
- CA
- Canada
- Prior art keywords
- ray
- image area
- receptor
- disk
- slits
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
- G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
- G21K1/04—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
- A61B6/06—Diaphragms
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
- G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
- G01N23/043—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using fluoroscopic examination, with visual observation or video transmission of fluoroscopic images
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
- G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
- G21K1/025—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using multiple collimators, e.g. Bucky screens; other devices for eliminating undesired or dispersed radiation
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
- G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
- G21K1/04—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers
- G21K1/043—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers changing time structure of beams by mechanical means, e.g. choppers, spinning filter wheels
Abstract
ABSTRACT OF THE DISCLOSURE
In an X-ray system with a rotating disk having sector slits transmitting fan shaped X-ray beams from a source through a subject to the image area of an X-ray receptor an improved ratio S/P of X-rays (S) scattered from the subject to primary rays (P) forming a true image of the subject at the image area is realized if the dimensions of the system fall within the following ranges of dimensionless ratios:
(1) DW/RL is less than 0.5;
(2) D/L is greater than 0.15;
(3) LS*N/WD is greater than 0.15 and less than 0.6. In the above relationships, D is the distance of the disk from the X-ray source, W is the width of the X-ray image area spanned by the narrow beams, R is the radius of the disk, L is the distance between the X-ray source and the receptor, S* is the radially outermost slit width in the X-ray beam, and N is the number of slits whose beams simultaneously intersect the outer edge of the image area.
In an X-ray system with a rotating disk having sector slits transmitting fan shaped X-ray beams from a source through a subject to the image area of an X-ray receptor an improved ratio S/P of X-rays (S) scattered from the subject to primary rays (P) forming a true image of the subject at the image area is realized if the dimensions of the system fall within the following ranges of dimensionless ratios:
(1) DW/RL is less than 0.5;
(2) D/L is greater than 0.15;
(3) LS*N/WD is greater than 0.15 and less than 0.6. In the above relationships, D is the distance of the disk from the X-ray source, W is the width of the X-ray image area spanned by the narrow beams, R is the radius of the disk, L is the distance between the X-ray source and the receptor, S* is the radially outermost slit width in the X-ray beam, and N is the number of slits whose beams simultaneously intersect the outer edge of the image area.
Description
PATENT
~L~3~3~
ROTATING X-RAY MASK WITH SEIKO SLITS
BACKGROUND OF THE INVENTION
In diagnostic X-ray equipment unwanted X-ray scatter can be reduced by interposing a rotating X-ray-opaqUe masking disk with X-ray transparent slits between an X-ray tube and the subject under examination. These slits are pectoral with their divergent long sides defined by radii from the axis of the disk, and serve to confine the X-rays to a fan shaped beam with a narrow pectoral cross section sweeping across the subject. Examples of slit radiography appear in United States patents 2,730,566 (Burt, 4,315,146 (Ruin), and 4,404,591, (Boar).
A disk using a single slit for each exposure sweep must be sector shaped for uniform exposure across the image area of the subject, but gives rise to nonuniform scatter of X-rays from the subject. Scatter is quantified by the ratio S/P of X-rays scattered from the subject to the primary rays forming the true image of the subject. This scatter-to-primary ratio S/P is not uniform over the image area scanned by a single sector-shaped beam, and may be non uniform when disks with multiple slits are used to form a plurality of fan-shaped beams for each scan in a single X-ray exposure.
~L~3~3~
ROTATING X-RAY MASK WITH SEIKO SLITS
BACKGROUND OF THE INVENTION
In diagnostic X-ray equipment unwanted X-ray scatter can be reduced by interposing a rotating X-ray-opaqUe masking disk with X-ray transparent slits between an X-ray tube and the subject under examination. These slits are pectoral with their divergent long sides defined by radii from the axis of the disk, and serve to confine the X-rays to a fan shaped beam with a narrow pectoral cross section sweeping across the subject. Examples of slit radiography appear in United States patents 2,730,566 (Burt, 4,315,146 (Ruin), and 4,404,591, (Boar).
A disk using a single slit for each exposure sweep must be sector shaped for uniform exposure across the image area of the subject, but gives rise to nonuniform scatter of X-rays from the subject. Scatter is quantified by the ratio S/P of X-rays scattered from the subject to the primary rays forming the true image of the subject. This scatter-to-primary ratio S/P is not uniform over the image area scanned by a single sector-shaped beam, and may be non uniform when disks with multiple slits are used to form a plurality of fan-shaped beams for each scan in a single X-ray exposure.
- 2 - ~3~3~
I have discovered that uniform exposure and uniform scatter_to-primary ratio S/P over an image area can be achieved with multiple sector slits provided certain limits of the geometric parameters of the system are observed.
These limits are expressed in terms of dimensionless ratios and are thus general in scope.
~:3~3~
SUMMARY OF THE INVENTION
` According to- the invention an X-ray system for examining a subject comprises an X-ray source directing a dimensioned beam of X-radiation through a subject position;
an X-ray receptor with an image area in the beam beyond the subject position; and a rotating disk of radio-opaque material between the X-ray source and subject position, the disk having a plurality of spaced, sector-shaped X-ray slits in groups distributing X-radiation in narrow beams radially spanning the receptor image area and intersecting the outer edge of the image area while scanning the area during rotation of the disk; the dimensions of the system falling within the following ranges of dimensionless ratios:
(1) DOYLE is less than 0.5;
(2) D/L is greater than 0.15;
I have discovered that uniform exposure and uniform scatter_to-primary ratio S/P over an image area can be achieved with multiple sector slits provided certain limits of the geometric parameters of the system are observed.
These limits are expressed in terms of dimensionless ratios and are thus general in scope.
~:3~3~
SUMMARY OF THE INVENTION
` According to- the invention an X-ray system for examining a subject comprises an X-ray source directing a dimensioned beam of X-radiation through a subject position;
an X-ray receptor with an image area in the beam beyond the subject position; and a rotating disk of radio-opaque material between the X-ray source and subject position, the disk having a plurality of spaced, sector-shaped X-ray slits in groups distributing X-radiation in narrow beams radially spanning the receptor image area and intersecting the outer edge of the image area while scanning the area during rotation of the disk; the dimensions of the system falling within the following ranges of dimensionless ratios:
(1) DOYLE is less than 0.5;
(2) D/L is greater than 0.15;
(3) LS*N/WD is greater than 0.15 and less than 0.6 wherein D is the distance of the disk from the X-ray source, W is the width of the X-ray image area spanned by the narrow beams, R is the radius of the disk, L is the distance between the X-ray source and the receptor.
_ 4 _ ~3S~3~
S* is the radially outermost slit width in the X-ray beam, and is the number of slits whose beams Somali-tonsil intersect the outer edge of the image area whereby the quantity of scattered X-rays relative to Trays forming an image at the receptor is minimized and X-ray scatter is substantially uniform throughout the image area.
Preferably the system includes an X-ray screening grid between the subject position and image area.
_ 5 _ ~3~3~
DRAWING
FIG. 1 is a diagrammatic view of an X-ray system with a sector slit disk according to the invention; and FIG. 2 is an enlarged, fragmental plan view of the sector slit disk of FIG. 1.
- 6 5S3~
DESCRIPTION
The X-ray system of JIG. 1 consists of an X-ray tube XT with an anode A and a cathode K supplied with high voltage from an exposure control 1 to radiate Trays in a divergent beam from a focal spot source X along an axis Al.
From the source X the divergent X-ray beam passes through an image framing device F an an X-ray masking disk Do along the axis Al through the position P of a subject such as a human patient under examination on a table T, and thence through an X-ray screening grid H to an X-ray receptor OR.
The term framing device identifies a stationary X-ray-opaque shield which defines an image area IA at the receptor OR
and protects the patient from exposure to X-rays outside the image area. A suitable grid is available as Type No.
9862 054 84101 from Phillips Medical Systems, Shelton, Connecticut.
Although for the purposes of this invention the receptor OR may be an X-ray sensitive film or other X-ray responsive medium as shown the receptor is a scintillation screen producing a secondary, light image at it output area IA proportionate to received X-rays. The light image at the area IA is projected by lens optics o along a I
secondary, light axis A which is folded by a mirror M.
The projected light image passes through a light masking disk Do, similar to and synchronized with disk Do, onto the input face of a light image intensifier I optically coupled to a video tube VT such as an image isocon which converts the intensified light image into electrical video signal data. The video signal is applied through a data processor 3 to utilization means such as a video display 4 or recorder.
The X-ray mask Do shown in FIG. 2 is a disk of X-ray-opaque material such as tantalum, lead or uranium. Through the disk are X-ray transparent, sector shaped slits or apertures S whose long sides 6 are along radii from the center 5 of the disk ash slit transmits a fan shaped beam radially spanning the image area IA as it scans laterally across the area. The slits diverge radially outwardly of the disk, and are spaced apart in a group G, for example, approxi-mutely 40 slits distributed through an angle of approximately 90, 10 of which cover the radially outward edge E of the image area IA. The outer edge E intersects an arc S**
traversed by the radially outermost effective ends of slits The slits might extend further outwardly of this arc but ~;35533L
without effect. The significant slit width I* is the width of the slit along the arc S** where the fan beam from each slit intersects the corners of the image area IA a its radially outward edge E. The width W of the image area IA is the dimension of the image area spanned radially by the fan beam from each slit. This width W is shown at its actual location at the image area in EGO. 1, but is shown in FIG. 2 in reduced size W* by a reverse projection IA* of the image IA
area -from the receptor plane to the plane of the disk Do.
The projected image area IA* illustrates the same relation which the slits S have to the projected aria IA* as the fan shaped beams they transmit have to the actual image area IA
at the receptor R. In a disk of 10 centimeter radius the sector slits have a radially outer width near the disk periphery of 0,122 cm., for example. The spacing of the slits is determined by the dimensionless ratios described hereafter. As the X-ray-opa~ue disk Do rotates the sector slits S and their fan shaped beams scan laterally across the patient or other subject and across the image area.
9 ~3~i~i3~
In Figs 1 and 2 the disk Do and other components of the X-ray system have dimensions which, according to the present invention, can be selected, despite the divergent sector shape of the X-ray transmissive slits S, to hold the scatter-to-primary ratio S/P, substantially and practically uniform throughout the image area.
A substantially uniform scatter-to-primary ratio can be realized if the X-ray system meets the limitations of following three dimensionless ratios:
(1) DARRYL is less than 0.5;
(2) D/L is greater than 0.15;
(3) LS*N/WDis greater than 0.15; and less than 0.6.
The parameters of these ratios are shown in Figs 1 and 2, wherein:
D is the distance of the X-ray opaque disk Do from the X-ray source X.
W is the width of the X-ray image area spanned by the narrow fan beams, R is the radius of the disk Do, L is the distance between the X-ray source X and the receptor OR, S* is the radially outermost slit width in the X-ray beam, and g isle N is the number of slits S whose beams simultaneously intersect the outer edge of the image area during scanning of the image area.
Typical values of the above parameters satisfying the dimensionless ratios are:
R is 10 cm.
D is 20 cm.
W is 20 cm.
L is 100 cm.
S* is 0.122 cm.
N is 10 When the parameters defining the dimensionless ratios are specified the X-ray transmission of the slit group G, and the spacing between sector slits are specified.
Preferably these ratios also satisfy the limits -D/L is approximately 0~2 N is substantially equal to R
LS*N~WD is between 0.3 and 0.5.
A principal problem with multiple slits arises from the scatter of X-rays from one fan shaped beam spreading into neighboring beams This problem is significantly isle reduced by the presence Of the grid H between the subject position P and the image area IA.
It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.
_ 4 _ ~3S~3~
S* is the radially outermost slit width in the X-ray beam, and is the number of slits whose beams Somali-tonsil intersect the outer edge of the image area whereby the quantity of scattered X-rays relative to Trays forming an image at the receptor is minimized and X-ray scatter is substantially uniform throughout the image area.
Preferably the system includes an X-ray screening grid between the subject position and image area.
_ 5 _ ~3~3~
DRAWING
FIG. 1 is a diagrammatic view of an X-ray system with a sector slit disk according to the invention; and FIG. 2 is an enlarged, fragmental plan view of the sector slit disk of FIG. 1.
- 6 5S3~
DESCRIPTION
The X-ray system of JIG. 1 consists of an X-ray tube XT with an anode A and a cathode K supplied with high voltage from an exposure control 1 to radiate Trays in a divergent beam from a focal spot source X along an axis Al.
From the source X the divergent X-ray beam passes through an image framing device F an an X-ray masking disk Do along the axis Al through the position P of a subject such as a human patient under examination on a table T, and thence through an X-ray screening grid H to an X-ray receptor OR.
The term framing device identifies a stationary X-ray-opaque shield which defines an image area IA at the receptor OR
and protects the patient from exposure to X-rays outside the image area. A suitable grid is available as Type No.
9862 054 84101 from Phillips Medical Systems, Shelton, Connecticut.
Although for the purposes of this invention the receptor OR may be an X-ray sensitive film or other X-ray responsive medium as shown the receptor is a scintillation screen producing a secondary, light image at it output area IA proportionate to received X-rays. The light image at the area IA is projected by lens optics o along a I
secondary, light axis A which is folded by a mirror M.
The projected light image passes through a light masking disk Do, similar to and synchronized with disk Do, onto the input face of a light image intensifier I optically coupled to a video tube VT such as an image isocon which converts the intensified light image into electrical video signal data. The video signal is applied through a data processor 3 to utilization means such as a video display 4 or recorder.
The X-ray mask Do shown in FIG. 2 is a disk of X-ray-opaque material such as tantalum, lead or uranium. Through the disk are X-ray transparent, sector shaped slits or apertures S whose long sides 6 are along radii from the center 5 of the disk ash slit transmits a fan shaped beam radially spanning the image area IA as it scans laterally across the area. The slits diverge radially outwardly of the disk, and are spaced apart in a group G, for example, approxi-mutely 40 slits distributed through an angle of approximately 90, 10 of which cover the radially outward edge E of the image area IA. The outer edge E intersects an arc S**
traversed by the radially outermost effective ends of slits The slits might extend further outwardly of this arc but ~;35533L
without effect. The significant slit width I* is the width of the slit along the arc S** where the fan beam from each slit intersects the corners of the image area IA a its radially outward edge E. The width W of the image area IA is the dimension of the image area spanned radially by the fan beam from each slit. This width W is shown at its actual location at the image area in EGO. 1, but is shown in FIG. 2 in reduced size W* by a reverse projection IA* of the image IA
area -from the receptor plane to the plane of the disk Do.
The projected image area IA* illustrates the same relation which the slits S have to the projected aria IA* as the fan shaped beams they transmit have to the actual image area IA
at the receptor R. In a disk of 10 centimeter radius the sector slits have a radially outer width near the disk periphery of 0,122 cm., for example. The spacing of the slits is determined by the dimensionless ratios described hereafter. As the X-ray-opa~ue disk Do rotates the sector slits S and their fan shaped beams scan laterally across the patient or other subject and across the image area.
9 ~3~i~i3~
In Figs 1 and 2 the disk Do and other components of the X-ray system have dimensions which, according to the present invention, can be selected, despite the divergent sector shape of the X-ray transmissive slits S, to hold the scatter-to-primary ratio S/P, substantially and practically uniform throughout the image area.
A substantially uniform scatter-to-primary ratio can be realized if the X-ray system meets the limitations of following three dimensionless ratios:
(1) DARRYL is less than 0.5;
(2) D/L is greater than 0.15;
(3) LS*N/WDis greater than 0.15; and less than 0.6.
The parameters of these ratios are shown in Figs 1 and 2, wherein:
D is the distance of the X-ray opaque disk Do from the X-ray source X.
W is the width of the X-ray image area spanned by the narrow fan beams, R is the radius of the disk Do, L is the distance between the X-ray source X and the receptor OR, S* is the radially outermost slit width in the X-ray beam, and g isle N is the number of slits S whose beams simultaneously intersect the outer edge of the image area during scanning of the image area.
Typical values of the above parameters satisfying the dimensionless ratios are:
R is 10 cm.
D is 20 cm.
W is 20 cm.
L is 100 cm.
S* is 0.122 cm.
N is 10 When the parameters defining the dimensionless ratios are specified the X-ray transmission of the slit group G, and the spacing between sector slits are specified.
Preferably these ratios also satisfy the limits -D/L is approximately 0~2 N is substantially equal to R
LS*N~WD is between 0.3 and 0.5.
A principal problem with multiple slits arises from the scatter of X-rays from one fan shaped beam spreading into neighboring beams This problem is significantly isle reduced by the presence Of the grid H between the subject position P and the image area IA.
It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.
Claims (7)
1. An X-ray system for examining a subject comprising:
an X-ray source directing a dimensioned beam of X-radiation through a subject position;
an X-ray receptor with an image area in the beam beyond the subject position; and a rotating disk of radio-opaque material between the X-ray source and subject position, the disk having a plurality of spaced, sector-shaped X-ray slits in groups distributing X-radiation in narrow beams radially spanning the receptor image area and intersecting the outer edge of the image area while scanning the area during rotation of the disk;
the dimensions of the system falling within the following ranges of dimensionless ratios:
(1) DW/RL is less than 0.5;
(2) D/L is greater than 0.15;
(3) LS*N/WD is greater than 0.15 and less than 0.6 wherein D is the distance of the disk from the X-ray source, W is the width of the X-ray image axe spanned by the narrow beams, R is the radius of the disk, L is the distance between the X-ray source and the receptor.
S* is the radially outermost slit width in the X-ray beam, and N is the number of slits whose beams simultaneously intersect the outer edge of the image area, whereby the quantity of scattered X-rays relative to X-rays forming an image at the receptor is minimized and X-ray scatter is substantially uniform throughout the image area.
an X-ray source directing a dimensioned beam of X-radiation through a subject position;
an X-ray receptor with an image area in the beam beyond the subject position; and a rotating disk of radio-opaque material between the X-ray source and subject position, the disk having a plurality of spaced, sector-shaped X-ray slits in groups distributing X-radiation in narrow beams radially spanning the receptor image area and intersecting the outer edge of the image area while scanning the area during rotation of the disk;
the dimensions of the system falling within the following ranges of dimensionless ratios:
(1) DW/RL is less than 0.5;
(2) D/L is greater than 0.15;
(3) LS*N/WD is greater than 0.15 and less than 0.6 wherein D is the distance of the disk from the X-ray source, W is the width of the X-ray image axe spanned by the narrow beams, R is the radius of the disk, L is the distance between the X-ray source and the receptor.
S* is the radially outermost slit width in the X-ray beam, and N is the number of slits whose beams simultaneously intersect the outer edge of the image area, whereby the quantity of scattered X-rays relative to X-rays forming an image at the receptor is minimized and X-ray scatter is substantially uniform throughout the image area.
2. A system according to claim 1 including a stationary X-ray screening grid between the subject position and the image area.
3. A system according to claim 1 wherein the X-ray receptor produces a light image and the system includes a light receptor and a rotating disk of light-opaque material and light-transparent sector slits between the X-ray receptor and slight receptor.
4. A system according to claim 1 wherein the ratio D/L is greater than 0.15.
5. A system according to claim 1 wherein N is substantially equal to R.
6. A system according to claim 1 wherein the ratio L/D is approximately 0.2.
7. A system according to claim 1 wherein the ratio LS*N/WD is between 0.3 and 0.5.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US743,386 | 1985-06-11 | ||
| US06/743,386 US4646339A (en) | 1985-06-11 | 1985-06-11 | Rotating X-ray mask with sector slits |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1235531A true CA1235531A (en) | 1988-04-19 |
Family
ID=24988594
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000504552A Expired CA1235531A (en) | 1985-06-11 | 1986-03-19 | Rotating x-ray mask with sector slits |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4646339A (en) |
| CA (1) | CA1235531A (en) |
| DE (1) | DE3619027A1 (en) |
| FR (1) | FR2582928A1 (en) |
| GB (1) | GB2176380B (en) |
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| DE102016221205B4 (en) | 2016-10-27 | 2018-07-26 | Siemens Healthcare Gmbh | Method for generating X-ray images and X-ray system |
| US10770195B2 (en) | 2017-04-05 | 2020-09-08 | Viken Detection Corporation | X-ray chopper wheel assembly |
| WO2019245636A1 (en) | 2018-06-20 | 2019-12-26 | American Science And Engineering, Inc. | Wavelength-shifting sheet-coupled scintillation detectors |
| WO2021247615A1 (en) | 2020-06-02 | 2021-12-09 | Viken Detection Corporation | X-ray imaging apparatus and method |
| US11175245B1 (en) | 2020-06-15 | 2021-11-16 | American Science And Engineering, Inc. | Scatter X-ray imaging with adaptive scanning beam intensity |
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| US3780291A (en) * | 1971-07-07 | 1973-12-18 | American Science & Eng Inc | Radiant energy imaging with scanning pencil beam |
| GB1475492A (en) * | 1973-06-01 | 1977-06-01 | Emi Ltd | Apparatus for examining objects by means of penetrating radiation |
| US4315146A (en) * | 1979-08-17 | 1982-02-09 | The Research Foundation Of State University Of New York | Process and apparatus for scatter reduction in radiography |
| US4403338A (en) * | 1980-11-14 | 1983-09-06 | Stephen Rudin | Process and apparatus for scatter reduction in radiography |
| US4404591A (en) * | 1982-01-04 | 1983-09-13 | North American Philips Corporation | Slit radiography |
| US4433427A (en) * | 1982-01-26 | 1984-02-21 | Elscint, Inc. | Method and apparatus for examining a body by means of penetrating radiation such as X-rays |
| US4534051A (en) * | 1982-12-27 | 1985-08-06 | John K. Grady | Masked scanning X-ray apparatus |
| US4896344A (en) * | 1984-10-15 | 1990-01-23 | Grady John K | X-ray video system |
-
1985
- 1985-06-11 US US06/743,386 patent/US4646339A/en not_active Expired - Fee Related
- 1985-11-18 GB GB08528324A patent/GB2176380B/en not_active Expired
-
1986
- 1986-01-20 FR FR8600689A patent/FR2582928A1/en not_active Withdrawn
- 1986-03-19 CA CA000504552A patent/CA1235531A/en not_active Expired
- 1986-06-06 DE DE19863619027 patent/DE3619027A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB8528324D0 (en) | 1985-12-24 |
| GB2176380A (en) | 1986-12-17 |
| GB2176380B (en) | 1988-12-21 |
| FR2582928A1 (en) | 1986-12-12 |
| US4646339A (en) | 1987-02-24 |
| DE3619027A1 (en) | 1986-12-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |