CA1123974A - X-ray tomographic scanning - Google Patents
X-ray tomographic scanningInfo
- Publication number
- CA1123974A CA1123974A CA271,364A CA271364A CA1123974A CA 1123974 A CA1123974 A CA 1123974A CA 271364 A CA271364 A CA 271364A CA 1123974 A CA1123974 A CA 1123974A
- Authority
- CA
- Canada
- Prior art keywords
- array
- radiant energy
- source
- axis
- imaging apparatus
- 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
- 238000003384 imaging method Methods 0.000 claims description 9
- 230000000149 penetrating effect Effects 0.000 claims description 3
- 238000006073 displacement reaction Methods 0.000 claims 1
- 230000005855 radiation Effects 0.000 abstract description 4
- 238000000034 method Methods 0.000 description 10
- 238000005259 measurement Methods 0.000 description 6
- 238000005070 sampling Methods 0.000 description 5
- 230000033001 locomotion Effects 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 238000003325 tomography Methods 0.000 description 3
- 238000013480 data collection Methods 0.000 description 2
- 238000013519 translation Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- RNIHAPSVIGPAFF-UHFFFAOYSA-N Acrylamide-acrylic acid resin Chemical compound NC(=O)C=C.OC(=O)C=C RNIHAPSVIGPAFF-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000029058 respiratory gaseous exchange Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
- A61B6/4275—Arrangements for detecting radiation specially adapted for radiation diagnosis using a detector unit almost surrounding the patient, e.g. more than 180°
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
- A61B6/03—Computed tomography [CT]
- A61B6/032—Transmission computed tomography [CT]
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Medical Informatics (AREA)
- Radiology & Medical Imaging (AREA)
- Molecular Biology (AREA)
- Biophysics (AREA)
- High Energy & Nuclear Physics (AREA)
- Veterinary Medicine (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Optics & Photonics (AREA)
- Pathology (AREA)
- Public Health (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Physics & Mathematics (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Pulmonology (AREA)
- Theoretical Computer Science (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
- Apparatus For Radiation Diagnosis (AREA)
- Developing Agents For Electrophotography (AREA)
- Photoreceptors In Electrophotography (AREA)
- Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A radiographic apparatus where a rotating X-ray source scans a fan beam of radiation through an area of interest coplanar with the beam, and along a stationary circular array of detectors, During a revolution of the source, each detector produces a sequence of signals indicative of radiation indensity received, and those signals are processed to provide and image representative of the X-ray transmissivity of the scanned area.
A radiographic apparatus where a rotating X-ray source scans a fan beam of radiation through an area of interest coplanar with the beam, and along a stationary circular array of detectors, During a revolution of the source, each detector produces a sequence of signals indicative of radiation indensity received, and those signals are processed to provide and image representative of the X-ray transmissivity of the scanned area.
Description
~IZ3~7~
M AME P63 BAC~GROUND OF THE INV~TION
CH/ck 9717~/76 The present invention relates in general to radiant energy imaging and more particularly concerns novel apparatus cross and techniques for obtaining/sectional images of patients for diagnostic purposes. The invention is characterized ~y high resolution and speed and a number of other features which make it advantageous for use in computerized tomography.
Various techniques and measurement geometries may be high speed used for/computerized tomography. One technique utilizes an X-ray source and a detector array, in fixed relationship, trans-lated past the patient. A fan beam, impinging on a - detector array, produces a fan of measurements at varying angles at any given moment. During the translation, each detecto~
records a set of parallel measurements at one of these angles.
To acquire measurements at a new group of angles, the source-detector structure is rotated and then translated again. The advantages of this two-motion technique are: (1) high sampling may be resolution because each detector / sampled many times as it scans across a patient, ~2) no gain matching requirement because each detector scans across the entire patient, and (3) the feasibility of frequent calibration before and after each scan.
The disadvantages are: ~1) slowness due to the mechanical limitations of the two-motion technique and (2) the small ~an beam angle, needed to enable faster translation, which wastes useful X-rays.
A different scanning technique again uses a fan beam source and a detector array in figed relationship, but the structure is rotated about the patient with no translating motion.
Each detector records X-ray measurements tangent to a fixed circle.
This one-motion technique has the advantages of ~1) high scanning speeds because only one mechanical motion is required and (2) the feasibility of using a large fan angle. However7 its cLisadvantagPs 3~
~ ~ ~3~3~ ~
AA ~YE P63include (1) low sampling resolution due to the many tiny, closely CH/ck 9/17/76 spaced detectors required for fine sampling, (2) gain matching requirements because each detector does not scan across the entire patient, and (3) the impossibility of frequent calibration because calibration can only be achieved after removal of the patient as each detector does not scan across the entire patient.
It is an important object of this invention to provide an improved computerized tomography system.
It is another object of the invention to achieve the preceding object with a system that achieves high sampling resolution.
It is a further object of the invention to achieve one or more of the preceding objects with a system that does not require close matching in gain between detectors.
It is still a further object of the invention to achieve one or more of the preceding objects with a system that allows fre~uent calibration of detectors.
It is still a further object of the invention to achieve one or more of the preceding objects with a system that - 20 achieves high-speed scanning.
It is still a further object of the invention to achieve one or more of the preceding objects with a system that can utilize an X-ray fan beam of a large angle.
SUMMARY OF TME I~VENTIOM
According to the invention, there is a source of penetrating radiant energy, such as gamma or X-ray, which revolves concentrically within or without a s-tationary circular array of detectors- The source emits a fan beam which passes through the patient circle centered at the axis of rotation and illuminates a number of detectors simultaneously to provide a corresponding plurality of detected signals each representative of the radiant energy transmissivity ~L123~7~
AA AME P63between the source and a respective detector. Signal processing CH7ck 9/17/76 means combine the detected signals to provide a cross sectionaL image representative of the radiant energy transmissivity of the scanned region.
Numerous other features, objects and advantages o the invention will become apparent from the following specifica-tion when read in connection with the accompanying drawing in which:
: BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a combined block-diagrammatic representation of rotating X-ray source and stationary detector array configuration according to the invention; and FIG. 2 is a graphical representation of the geometry of the X-ray measurements recorded by one detector during one revolution of the X-ray source.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
With reference now to the drawing and more particularly FIG. 1 thereof, there is shown a combined block-diagrammatic ` representation of a rotating X-ray source and stationary detector array configuration according to the invention. X-ray source 11 rotates about axis 12 and emits a fan beam 13 of X-rays through ' an angle sufficiently wide to illuminate patient circle 14 i~ centered on axis 12. As X-ray source 11 revolves, fan beam 13 ~! illuminates a concentric, stationary, circular array 15 of scintillation detectors 16. At a given moment, beam 13 illuminates a contiguous group of individual detectors 16 simultaneously to provide a corresponding number of detected electrical signals each representative o~ the X-ray transmissivity between source 11 and a respective one of detectors 16. Signal processing means 17 is connected to detectors 16 for combining the de-tected ~ output signals to provide an image signal representative of the ;~ cross X-ray transmissivity of a/section of the patient within patient ~j; -4-;:
~23~Y~
AA AM~ P63 circle 14 just scanned. Imaging means 21 is responsive to the OEl/ck cross ~7~776 image signal ~or providing a visual image of the scanned/section.
The scanning system and patien~ may be relatively displaced axially to produce a sequence of images of corresponding axially cross displaced/sections.
Referring now to FIG. 2, there is shown a graphical representation of the geometry showing the sequence o radiation directions 22 between source 11 and one detector 16' during one revolution of X-ray source 11. Detector 16' is illuminated by fan beam 13 during a portion of a revolution of X-ray source 11. As X-ray source 11 moves through that portion of its revolution, de-tector 16' receives radiation primarily along a sequence of direc-tions 22 as source ll moves along an arc t~at subtends an angle embracing the entirety of patient circle 14. A similar sequence occurs for each of detectors 16 during one complete revolution of ~- X ray source 11. Signal processing means 17 combines the signals ~rom all detectors 16 to pro~ide a high-~uality cross sectional image signal or axial t~logram transverse/according to well-known techniques using digital computer processing. Imaging means 21 displays a visualimage of the tomogram.
~ 20 The invention is characterized by a number of features `~ that enable it to produce high-quality computerized tomograms without the disadvantages of other sys~ems. The invention achieves high sampling resolution because each detector 16 may be sampled many times as source 11 revolves around the patient.
Close gain matching is not required because each detector 16 collects data across the entire patient. A mismatch in gain will ; cause only a small DC offset in the final reconstructed image.
Another advantageous feature is that calibration of detectors 16 may be accomplished during each scan, so that removal of the patient is not necessary ~or each calibration and frequent calibration is possible.
Further desirable features include high-speed data collectiorl, due to -the single mechanical mot,ion (rotation of source 11), and the feasibil:ity of using a large angle for fan beam 13, which reduces waste of useful X-rays and allows more efficient clata collection. The high speed of the data collec-tion is desirable to eliminate the effects of the patient's breathing motion and other body motions.
In an e~emplary embodiment of the invention actually constructed and successfully operated to produce a high resolu-tion tomogram, there were 600 individual cletectors in the array illuminated by an X-ray fan beam spanning an angle of substan-tially 50 degrees about the a~is of rotation and abou-t 2-10 mm.
alony its axis. An X-ray source of energy up to lS0 kv at 100 ma, capable of completing a rotational s~an in 5, 10 or 20 seconds is used, A Data General model Eclipse* computer corn-bined the 600 detected output signals converted into digital form by digital-to-analog converters using the techniques des-cribed in the State University o-f New York at Buffalo Computer Sciences Dept. Technical Report No. 92 dated January 1975 entitled "Reconstruction from Diveryent Ray Data" by A. V.
Lakshminarayanan, While rotating the source with patient and circular array of detectors remaining stationary is the preferred form of the invention, it is within the principles of the invention to allow the X-ray source to remain stationary, and rotate the object beincl examined and the stationary detectors together.
'rhere has been descrihed a novel radiarl-t energy imaging system characterized by high resolution, high-speed data collection, and other features desirable in a computerized tornography system. It is evident tha-t those s]~illed in the ar-t may now make numerous uses and modifications of and departures * Trade maxk of Data General Corp.
~ ..,j ~ 6 -3~
from the specific e~mbodiments described herein without depart-ing from the inventive concepts. Consequently, the invention is to be construed as embracing each and every novel feature and novel combination of features present in or possessed by the apparatus and techniques therein disclosed and limited solely by the spirit and scope o the appended claims.
M AME P63 BAC~GROUND OF THE INV~TION
CH/ck 9717~/76 The present invention relates in general to radiant energy imaging and more particularly concerns novel apparatus cross and techniques for obtaining/sectional images of patients for diagnostic purposes. The invention is characterized ~y high resolution and speed and a number of other features which make it advantageous for use in computerized tomography.
Various techniques and measurement geometries may be high speed used for/computerized tomography. One technique utilizes an X-ray source and a detector array, in fixed relationship, trans-lated past the patient. A fan beam, impinging on a - detector array, produces a fan of measurements at varying angles at any given moment. During the translation, each detecto~
records a set of parallel measurements at one of these angles.
To acquire measurements at a new group of angles, the source-detector structure is rotated and then translated again. The advantages of this two-motion technique are: (1) high sampling may be resolution because each detector / sampled many times as it scans across a patient, ~2) no gain matching requirement because each detector scans across the entire patient, and (3) the feasibility of frequent calibration before and after each scan.
The disadvantages are: ~1) slowness due to the mechanical limitations of the two-motion technique and (2) the small ~an beam angle, needed to enable faster translation, which wastes useful X-rays.
A different scanning technique again uses a fan beam source and a detector array in figed relationship, but the structure is rotated about the patient with no translating motion.
Each detector records X-ray measurements tangent to a fixed circle.
This one-motion technique has the advantages of ~1) high scanning speeds because only one mechanical motion is required and (2) the feasibility of using a large fan angle. However7 its cLisadvantagPs 3~
~ ~ ~3~3~ ~
AA ~YE P63include (1) low sampling resolution due to the many tiny, closely CH/ck 9/17/76 spaced detectors required for fine sampling, (2) gain matching requirements because each detector does not scan across the entire patient, and (3) the impossibility of frequent calibration because calibration can only be achieved after removal of the patient as each detector does not scan across the entire patient.
It is an important object of this invention to provide an improved computerized tomography system.
It is another object of the invention to achieve the preceding object with a system that achieves high sampling resolution.
It is a further object of the invention to achieve one or more of the preceding objects with a system that does not require close matching in gain between detectors.
It is still a further object of the invention to achieve one or more of the preceding objects with a system that allows fre~uent calibration of detectors.
It is still a further object of the invention to achieve one or more of the preceding objects with a system that - 20 achieves high-speed scanning.
It is still a further object of the invention to achieve one or more of the preceding objects with a system that can utilize an X-ray fan beam of a large angle.
SUMMARY OF TME I~VENTIOM
According to the invention, there is a source of penetrating radiant energy, such as gamma or X-ray, which revolves concentrically within or without a s-tationary circular array of detectors- The source emits a fan beam which passes through the patient circle centered at the axis of rotation and illuminates a number of detectors simultaneously to provide a corresponding plurality of detected signals each representative of the radiant energy transmissivity ~L123~7~
AA AME P63between the source and a respective detector. Signal processing CH7ck 9/17/76 means combine the detected signals to provide a cross sectionaL image representative of the radiant energy transmissivity of the scanned region.
Numerous other features, objects and advantages o the invention will become apparent from the following specifica-tion when read in connection with the accompanying drawing in which:
: BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a combined block-diagrammatic representation of rotating X-ray source and stationary detector array configuration according to the invention; and FIG. 2 is a graphical representation of the geometry of the X-ray measurements recorded by one detector during one revolution of the X-ray source.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
With reference now to the drawing and more particularly FIG. 1 thereof, there is shown a combined block-diagrammatic ` representation of a rotating X-ray source and stationary detector array configuration according to the invention. X-ray source 11 rotates about axis 12 and emits a fan beam 13 of X-rays through ' an angle sufficiently wide to illuminate patient circle 14 i~ centered on axis 12. As X-ray source 11 revolves, fan beam 13 ~! illuminates a concentric, stationary, circular array 15 of scintillation detectors 16. At a given moment, beam 13 illuminates a contiguous group of individual detectors 16 simultaneously to provide a corresponding number of detected electrical signals each representative o~ the X-ray transmissivity between source 11 and a respective one of detectors 16. Signal processing means 17 is connected to detectors 16 for combining the de-tected ~ output signals to provide an image signal representative of the ;~ cross X-ray transmissivity of a/section of the patient within patient ~j; -4-;:
~23~Y~
AA AM~ P63 circle 14 just scanned. Imaging means 21 is responsive to the OEl/ck cross ~7~776 image signal ~or providing a visual image of the scanned/section.
The scanning system and patien~ may be relatively displaced axially to produce a sequence of images of corresponding axially cross displaced/sections.
Referring now to FIG. 2, there is shown a graphical representation of the geometry showing the sequence o radiation directions 22 between source 11 and one detector 16' during one revolution of X-ray source 11. Detector 16' is illuminated by fan beam 13 during a portion of a revolution of X-ray source 11. As X-ray source 11 moves through that portion of its revolution, de-tector 16' receives radiation primarily along a sequence of direc-tions 22 as source ll moves along an arc t~at subtends an angle embracing the entirety of patient circle 14. A similar sequence occurs for each of detectors 16 during one complete revolution of ~- X ray source 11. Signal processing means 17 combines the signals ~rom all detectors 16 to pro~ide a high-~uality cross sectional image signal or axial t~logram transverse/according to well-known techniques using digital computer processing. Imaging means 21 displays a visualimage of the tomogram.
~ 20 The invention is characterized by a number of features `~ that enable it to produce high-quality computerized tomograms without the disadvantages of other sys~ems. The invention achieves high sampling resolution because each detector 16 may be sampled many times as source 11 revolves around the patient.
Close gain matching is not required because each detector 16 collects data across the entire patient. A mismatch in gain will ; cause only a small DC offset in the final reconstructed image.
Another advantageous feature is that calibration of detectors 16 may be accomplished during each scan, so that removal of the patient is not necessary ~or each calibration and frequent calibration is possible.
Further desirable features include high-speed data collectiorl, due to -the single mechanical mot,ion (rotation of source 11), and the feasibil:ity of using a large angle for fan beam 13, which reduces waste of useful X-rays and allows more efficient clata collection. The high speed of the data collec-tion is desirable to eliminate the effects of the patient's breathing motion and other body motions.
In an e~emplary embodiment of the invention actually constructed and successfully operated to produce a high resolu-tion tomogram, there were 600 individual cletectors in the array illuminated by an X-ray fan beam spanning an angle of substan-tially 50 degrees about the a~is of rotation and abou-t 2-10 mm.
alony its axis. An X-ray source of energy up to lS0 kv at 100 ma, capable of completing a rotational s~an in 5, 10 or 20 seconds is used, A Data General model Eclipse* computer corn-bined the 600 detected output signals converted into digital form by digital-to-analog converters using the techniques des-cribed in the State University o-f New York at Buffalo Computer Sciences Dept. Technical Report No. 92 dated January 1975 entitled "Reconstruction from Diveryent Ray Data" by A. V.
Lakshminarayanan, While rotating the source with patient and circular array of detectors remaining stationary is the preferred form of the invention, it is within the principles of the invention to allow the X-ray source to remain stationary, and rotate the object beincl examined and the stationary detectors together.
'rhere has been descrihed a novel radiarl-t energy imaging system characterized by high resolution, high-speed data collection, and other features desirable in a computerized tornography system. It is evident tha-t those s]~illed in the ar-t may now make numerous uses and modifications of and departures * Trade maxk of Data General Corp.
~ ..,j ~ 6 -3~
from the specific e~mbodiments described herein without depart-ing from the inventive concepts. Consequently, the invention is to be construed as embracing each and every novel feature and novel combination of features present in or possessed by the apparatus and techniques therein disclosed and limited solely by the spirit and scope o the appended claims.
Claims (5)
1. Radiant energy imaging apparatus comprising, a source of a fan beam of penetrating radiant energy, an array of contiguous radiant energy detecting means located about an axis of rotation for converting incident penetrating radiant energy into a corresponding detected signal, and means for angularly relatively displacing said source and said array about said axis to sequentially illuminate different groups of said detecting means to provide a sequence of detected signals representative of the radiant energy response of the region between the path traveled by said source and said array.
2. Radiant energy imaging apparatus in accordance with claim 1 and further comprising, means for combining all said detected signals to provide an image signal, and means responsive to said image signal for produc-ing an image representative of said radian-t energy response.
3. Radiant energy imaging apparatus in accordance with claim 1 wherein said array encloses said axis of rotation and said source is located inside of said array and spaced from said axis.
4. Radiant energy imaging apparatus in accordance with claim 3 wherein said array is circular with its center on said axis and the path of relative displacement between said source and said array is a circle inside of and concentric with said array.
5. Radiant energy imaging apparatus in accordance with claim 4 wherein said array is stationary and said source rotates about said axis.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US72655676A | 1976-09-27 | 1976-09-27 | |
| US726,556 | 1976-09-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1123974A true CA1123974A (en) | 1982-05-18 |
Family
ID=24919078
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA271,364A Expired CA1123974A (en) | 1976-09-27 | 1977-02-04 | X-ray tomographic scanning |
Country Status (30)
| Country | Link |
|---|---|
| JP (1) | JPS5341989A (en) |
| AR (1) | AR215907A1 (en) |
| AT (1) | AT380165B (en) |
| AU (1) | AU508455B2 (en) |
| BE (1) | BE851918A (en) |
| BR (1) | BR7706396A (en) |
| CA (1) | CA1123974A (en) |
| CH (1) | CH616582A5 (en) |
| DD (1) | DD133399A5 (en) |
| DE (1) | DE2728815A1 (en) |
| DK (1) | DK82777A (en) |
| ES (1) | ES462511A1 (en) |
| FI (1) | FI61803C (en) |
| FR (1) | FR2365329A1 (en) |
| GB (1) | GB1539685A (en) |
| GR (1) | GR62632B (en) |
| HK (1) | HK43383A (en) |
| HU (1) | HU176639B (en) |
| IE (1) | IE45698B1 (en) |
| IL (1) | IL51336A (en) |
| IT (1) | IT1078364B (en) |
| MX (1) | MX143749A (en) |
| MY (1) | MY8300053A (en) |
| NL (1) | NL7709973A (en) |
| NO (1) | NO148209C (en) |
| PT (1) | PT67049B (en) |
| SE (1) | SE420158B (en) |
| SU (1) | SU650521A3 (en) |
| YU (1) | YU227277A (en) |
| ZA (1) | ZA775457B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3001103A1 (en) * | 1980-01-14 | 1981-07-16 | Siemens AG, 1000 Berlin und 8000 München | Transverse layer image computer tomograph - has ring of detectors narrowing trapezoidally towards scanning rotation centre |
| JPS61209641A (en) * | 1985-03-15 | 1986-09-17 | 株式会社東芝 | X-ray ct apparatus |
| EP0286393B1 (en) * | 1987-04-10 | 1992-11-19 | British Aerospace Public Limited Company | Imaging system |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1283915A (en) * | 1968-08-23 | 1972-08-02 | Emi Ltd | A method of and apparatus for examination of a body by radiation such as x or gamma radiation |
| DE2024037B2 (en) * | 1970-05-16 | 1980-01-17 | Koch & Sterzel Gmbh & Co, 4300 Essen | Multiple axis X=ray examination appts - has chair adjustable in three directions and turning with bracket parallel to floor |
| DE2442809A1 (en) * | 1974-09-06 | 1976-03-18 | Philips Patentverwaltung | ARRANGEMENT FOR DETERMINING ABSORPTION IN A BODY |
| GB1529799A (en) * | 1974-11-13 | 1978-10-25 | Emi Ltd | Radiography |
| NL181622C (en) * | 1975-02-21 | 1987-10-01 | Emi Ltd | RADIO CONTROLLER. |
| FR2304321A1 (en) * | 1975-03-20 | 1976-10-15 | Emi Ltd | X-ray scanning system - with multiple detectors providing detailed absorption data for a body under examination |
| GB1571510A (en) * | 1976-02-25 | 1980-07-16 | Emi Ltd | Radiography |
| GB1571509A (en) * | 1976-03-03 | 1980-07-16 | Emi Ltd | Radiography |
| JPS558167A (en) * | 1978-07-04 | 1980-01-21 | Pioneer Electronic Corp | Voltage setting circuit |
-
1977
- 1977-01-26 IL IL51336A patent/IL51336A/en unknown
- 1977-01-27 GR GR52661A patent/GR62632B/en unknown
- 1977-01-31 FR FR7702654A patent/FR2365329A1/en active Granted
- 1977-02-01 IT IT19856/77A patent/IT1078364B/en active
- 1977-02-04 CA CA271,364A patent/CA1123974A/en not_active Expired
- 1977-02-25 DK DK82777A patent/DK82777A/en not_active Application Discontinuation
- 1977-02-28 BE BE175341A patent/BE851918A/en not_active IP Right Cessation
- 1977-03-23 JP JP3200377A patent/JPS5341989A/en active Pending
- 1977-03-30 SE SE7703692A patent/SE420158B/en not_active IP Right Cessation
- 1977-06-22 CH CH767577A patent/CH616582A5/en not_active IP Right Cessation
- 1977-06-27 DE DE19772728815 patent/DE2728815A1/en not_active Ceased
- 1977-09-08 AT AT0647277A patent/AT380165B/en not_active IP Right Cessation
- 1977-09-12 ZA ZA00775457A patent/ZA775457B/en unknown
- 1977-09-12 NL NL7709973A patent/NL7709973A/en not_active Application Discontinuation
- 1977-09-16 FI FI772730A patent/FI61803C/en not_active IP Right Cessation
- 1977-09-19 PT PT67049A patent/PT67049B/en unknown
- 1977-09-21 ES ES462511A patent/ES462511A1/en not_active Expired
- 1977-09-21 AU AU28979/77A patent/AU508455B2/en not_active Expired
- 1977-09-23 DD DD77201184A patent/DD133399A5/en unknown
- 1977-09-23 NO NO773279A patent/NO148209C/en unknown
- 1977-09-26 AR AR269334A patent/AR215907A1/en active
- 1977-09-26 YU YU02272/77A patent/YU227277A/en unknown
- 1977-09-26 SU SU772529050A patent/SU650521A3/en active
- 1977-09-26 GB GB39968/77A patent/GB1539685A/en not_active Expired
- 1977-09-26 BR BR7706396A patent/BR7706396A/en unknown
- 1977-09-26 HU HU77AE512A patent/HU176639B/en unknown
- 1977-09-27 MX MX170706A patent/MX143749A/en unknown
- 1977-09-27 IE IE1973/77A patent/IE45698B1/en unknown
-
1983
- 1983-10-20 HK HK433/83A patent/HK43383A/en unknown
- 1983-12-30 MY MY53/83A patent/MY8300053A/en unknown
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