US3873833A - Electron radiographic system with liquid absorber - Google Patents

Electron radiographic system with liquid absorber Download PDF

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Publication number
US3873833A
US3873833A US456532A US45653274A US3873833A US 3873833 A US3873833 A US 3873833A US 456532 A US456532 A US 456532A US 45653274 A US45653274 A US 45653274A US 3873833 A US3873833 A US 3873833A
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US
United States
Prior art keywords
liquid
gap
electrodes
electrons
dielectric sheet
Prior art date
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Expired - Lifetime
Application number
US456532A
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English (en)
Inventor
Frank V Allan
John H Lewis
Katherine J Lewis
Arthur L Morsell
Eric P Muntz
Paul B Scott
Murray S Welkowsky
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ELSCINT IMAGING Inc
Elscint Ltd
Elscint Inc
Original Assignee
Xonics Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Xonics Inc filed Critical Xonics Inc
Priority to US456532A priority Critical patent/US3873833A/en
Priority to CA219,969A priority patent/CA1030207A/en
Priority to NL7501953A priority patent/NL7501953A/xx
Priority to DE19752507147 priority patent/DE2507147A1/de
Priority to IT48368/75A priority patent/IT1029880B/it
Priority to FR757506379A priority patent/FR2266201B1/fr
Priority to GB860375A priority patent/GB1454976A/en
Priority to BE153894A priority patent/BE826157A/xx
Application granted granted Critical
Publication of US3873833A publication Critical patent/US3873833A/en
Priority to JP3863275A priority patent/JPS5542758B2/ja
Assigned to ELSCINT, LIMITED, ELSCINT, INC., ELSCINT IMAGING, INC. reassignment ELSCINT, LIMITED ASSIGNORS DO HEREBY QUITCLAIM, ASSIGN AND TRANSFER THEIR ENTIRE RIGHTS, TITLE AND INTEREST THEY MAY HAVE IN SAID INVENTIN TO ASSIGNEES Assignors: XONICS MEDICAL SYSTEMS, INC., XONICS, INC.
Assigned to XONICS INC., A CA. CORP. reassignment XONICS INC., A CA. CORP. RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: FIRST CHICAGO INVESTMENT CORPORATION, AS AGENT
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/054—Apparatus for electrographic processes using a charge pattern using X-rays, e.g. electroradiography
    • G03G15/0545—Ionography, i.e. X-rays induced liquid or gas discharge
    • 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

Definitions

  • the 56 1 34 82 electrons and positive ions are attracted toward the [58] g 492 335 respective electrodes for deposit on the dielectric i 5 5 1 sheet to produce the latent electrostatic image.
  • the liquid is x-ray opaque and electrically nonconducting and may be a solvent with a gas or nonionic metallic [56] References Cited compounds dissolved therein, or may be in liquefied UNITED STATES PATENTS gas. 3,774,029 ll/l973 Mutz et al 250/315 12 Claims, 1 Drawing Figure :PL: 1 4?
  • This invention relates to electron radiographic systems of the type shown in U.S. Pat. No. 3,774,029 and in particular, to a new and improved system with a liquid adsorber in the gap between the electrodes in place of the conventional gas.
  • a dielectric receptor sheet is positioned at one of the electrode surfaces in a gap between a pair of electrodes.
  • a source of x-rays is directed to the gap past the object being xrayed, and incoming x-ray photons generate electrons and positive ions in the gap for attraction toward the respective electrodes.
  • Charges are collected on the dielectric receptor providing a latent electrostatic image of the object, and this image is developed to a visual image by standard xerographic techniques with the density of the deposited toner powder being a function of the magnitude of the electrostatic charge.
  • a radiopaque gas is maintained in the gap, typically of 8-15 mm width, at super atmospheric pressure, typically five to ten atmospheres. While the gas absorber systems provide highly satisfactory results, the production and maintenance of the high pressures in the gap result in problems in design, manufacture and operation of the imaging chambers or cassettes which hold dielectric receptor and gas during the x-ray exposure. Also, the 8-l5 mm gap required for the gas absorber system results in problems related to image resolution which necessitate the use of spherically shaped electrodes or a spherical electric field between the elecrodes as described in copending U.S. application, Ser. No. 388,212, filed Aug. 14, 1973.
  • the present invention is directed to a new and improved electron radiographic imaging system which may be operated at ambient pressure and with a gap less than mm and which utilizes a liquid as the x-ray absorber in place of the gas of the prior art devices.
  • One advantage to be derived from a liquid absorber is the requirement ofless gap thickness and, in the case of dissolved gases, less pressure for a desired quantum efficiency in the imaging system. Also, the substantially higher density of the liquid restricts the photoelectron range to a very small value essentially independent of pressure in the gap, with a resultant improvement in resolution.
  • radiopaque liquid x-ray absorber comprising liquified gases, liquids whose molecular structure includes heavy atoms, and heavy atom radiopaque material dissolved in a liquid solvent.
  • heavy atom is intended to mean atoms of atomic number 17 or greater. The limit of atomic number 17 is determined by the ratio of x-ray photons which are absorbed via the photoelectric process or scattered via the Compton collisional process within the imaging chamber.
  • the electrons and positive ions produced by photoelectric absorption are correlated witih the target (body) absorption whereas the electrons and positive ions produced by an x-ray photon which has undergone a Compton collision (path deflection) are not correlated with the target absorption and thus tend to degrade the image quality.
  • the ratio of photoelectric to Compton events for a typical x-ray photon of 50 KeV 2 is approximately one for an atom with atomic number 17. Since for atoms of lower atomic number the Compoton effect dominates, the useful limit for x-ray absorbers for imaging purposes is set at atomic number 17.
  • FIGURE of the drawing is a vertical sectional view of an x-ray imaging system employing a liquid absorber which may be a heavy atom liquid or a solvent with dissolved radiopaque material or a liquified gas.
  • a liquid absorber which may be a heavy atom liquid or a solvent with dissolved radiopaque material or a liquified gas.
  • An imaging system particularly adapted for making chest x-ray pictures is illustrated with an x-ray source 10 spaced from a receptor housing 11 and arranged so that the person or other object 12 to be x-rayed can be positioned between the x-ray source and the housing, preferably against the plate 13 of the housing.
  • a receptor supply roll 16, an imaging chamber 17, a liquid developer unit 18, and a toner fusing station 19 are provided within the housing 11. Hinged doors 20, 21 provide access to the interior of the housing.
  • the dielectric receptor sheet 25 is fed from the roll 16 through the imaging chamber 17, the developer unit 18 and the fusing station 19 by drive rolls and idler rolls as desired, and leaves the housing at an exit slot 26.
  • Other imaging chamber configurations including those shown in the prior art may be utilized as desired.
  • the imaging chamber 17 includes a vessel 30 with a U shaped passage 31 positioned within a channel portion 32 of the housing 1 1, preferably with thermal insulation material 33 placed about the vessel 30.
  • a refrigeration unit 34 is connected to the vessel 30 for maintaining the vessel and contents at a temperature below ambient.
  • Electrodes 37, 38 are mounted in the vessel 30 in spaced relation, defining a gap 39 therebetween.
  • the plate 13 of the housing, the insulation material 33, and the wall of the vessel 30 between the x-ray source and the electrode 37 should be made of materials having low x-ray absorbtion. Suitable materials for the electrodes 37, 38 are discussed in the aforesaid U.S. Pat. No. 3,774,029.
  • a high voltage supply 40 is connected acrosss the electrodes 37, 38 via switch 41 and leads 42, 43.
  • the receptor sheet 25 may be held in position against the electrode 37 by rollers 44, 45.
  • a liquid 50 is placed in the passage 31 of the vessel 30, filling the gap 39.
  • This iquid is an x-ray opaque electrically nonconducting liquid and in the embodiment illustrated comprises hexane with xenon dissolved therein.
  • the housing 11 is made substantially airtight and is charged with xenon at atmospheric pressure to reduce the likelihood of contamination of the hexane solvent by atmospheric constituents.
  • the amount of gas which can be dissolved into the solvent increases with a decrease in temperature of the solvent and it has been found that the amount of xenon which can be dissolved in hexane can be about doubled by maintaining the hexane at -20C.
  • the system can be operated at room temperature, eliminatto the housing via line 53. Both reduced temperatureand increased pressure may be employed to increase the xenon concentration in the liquid.
  • the electron radiographic system with the liquid in the gap between the electrodes operates in the same manner as the system of the aforementioned patent.
  • the incoming x-ray photons are absorbed by the liquid in the gap and electrons and positive ions are produced.
  • Electrons are attached toward the anode and the positive ions toward the cathode. Charges build up on the dielectric receptor forming a latent electrostatic image of the object exposed to the radiation. After the exposure, the receptor is advanced through the developer and the fusing station to provide the visual image and the resultant picture may be used in the same manner as the conventional x-ray picture.
  • the liquid absorber in the gap should be electrically nonconducting and should have an electrical resistivity greater than 10" ohmcentimeters when in use. A lower resistivity for the liquid tends to discharge any electrostatic image in contact with the liquid within a few seconds, thus making retrieval of the image very difficult.
  • the liquid should be x-ray opaque or radiopaque, that is, the liquid should absorb incoming x-ray photons and produce electrons and positive ions. Also, the absorbing atoms of the liquid should have an atomic number of at least l7 and preferably at least 35.
  • Krypton may be used in place of xenon for dissolving into the solvent.
  • suitable solvents include lsopar- G, P-Xylene, Toluene, Mesitylene, n Heptane, and certain commerical products such as Kerosine, Amsco 123-15. and Ultrasene. All ofthe above liquids have an Oswalds coefficient at room temperature for solubility of xenon which is greater than two and all of them can be purified to the extent that their electrical resistivity is at least l ohm-centimeters. However, the stability of certain compounds when subjected to x-rays varies and the most desirable for use in liquid absorbers are those which are the most stable such as n-hexane, nheptane, and lsopar G.
  • the number density of the primary x-ray absorbing atoms desirably is at least 10 absorbing atoms per cubic centimeter or liquid.
  • Other materials suitable for dissolving in the solvent include Bromine, lodine, and nonionic metallic compounds having an atomic number of at least l7 and preferably 35 or higher. as mixtures of such compounds. Examples of suitable non-ionic metallic compounds are sandwich compounds such as ferrocene and ruthenocene and related compounds.
  • lanthanide series elements such as La and Ce from non-ionic complexes with chelating compounds with the general formula where M denotes the metal atom and R,, R denote groups such as CH C H etc.
  • Tetravalent tin compounds such as SnCl, and Snl are also non-ionic. All useable materials including orgonometallic compounds of Pb for example, must form nonconducting solutions and be sufficiently soluable to attain the required concentration of absorbers in the solution.
  • the liquid in the gap between the electrodes may be a liquid the molecules of which include heavy atoms in their structure, with an atomic number of at least l7 and preferably with an atomic number of 30 to 36 and higher.
  • Suitable liquids include CCl,, CCl Br, CH l- CHFl CCl;,l, CH- Brl, CH- Cl l, CH Rl, CH Cl 21, other compounds of similar molecular composition containing elements of atomic number 17 or greater, and mixtures thereof.
  • liquids should have proper electrical resistivity (i.e., at least 10 ohm-centimeters), be sufficiently stable under x-ray radiation to maintain their characteristics during use preferably for several weeks, and in order to obtain an adequate quantum efficiency have a mass attenuation coefficient, ap (cm'-/gm), greater than 10 for a 50 KeV x-ray photon.
  • the liquid with molecules comprised of heavy atoms may be used in the apparatus of the drawing by placing it in the passage 31 of the vessel 30.
  • the system is usually operated at ambient temperature and ambient pressure, and the refrigeration unit and insulation material may be omitted.
  • the housing may be charged with an inert gas such as carbon dioxide to reduce the likelihood of contamination of the liquid.
  • Another embodiment is the use of liquified gases such as liquid xenon or krypton as the liquid absorber. ln this case, the imaging chamber would be operated at the liquification temperature (165K for xenon) and the receptor would pass out of the refrigerated gap to a warmer region charged with gaseous xenon or other gas for development.
  • liquified gases such as liquid xenon or krypton
  • liquid is a liquid with molecules including heavy atoms and selected from the gourp consisting of CCL, CClgBr, CH l CHFI CCl l, CH Brl, CH ClI, CH Rl, CHClgl, and mixtures thereof.
  • liquid comprises a nonconducting solvent having dissolved therein, a non-ionic material having atoms with an atomic number of at least 17.
  • said liquid comprises a nonconducting solvent having dissolved therein, a material selected from the group consisting of xenon. krypton, bromine, iodine, non ionic metallic compounds having an atomic number of at least l7, and mixtures thereof.
  • a system as defined in claim 5 including means for maintaining said liquid at a temperature below ambient.
  • a system as defined in claim 5 including means for maintaining said liquid at a pressure greater than ambient.
  • a system as defined in claim 8 including means for maintaining said liquid at a temperature below the boiling point of said gas.
  • a method of producing an electrostatic image on a dielectric sheet including the steps of:

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  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Pathology (AREA)
  • General Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Multimedia (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Radiology & Medical Imaging (AREA)
  • Immunology (AREA)
  • Engineering & Computer Science (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • X-Ray Techniques (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
US456532A 1974-04-01 1974-04-01 Electron radiographic system with liquid absorber Expired - Lifetime US3873833A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US456532A US3873833A (en) 1974-04-01 1974-04-01 Electron radiographic system with liquid absorber
CA219,969A CA1030207A (en) 1974-04-01 1975-02-13 Electron radiographic system with liquid absorber
NL7501953A NL7501953A (nl) 1974-04-01 1975-02-19 Elektroradiografisch stelsel.
DE19752507147 DE2507147A1 (de) 1974-04-01 1975-02-19 Elektronenradiographische einrichtung mit einer fluessigabsorptionsvorrichtung
IT48368/75A IT1029880B (it) 1974-04-01 1975-02-27 Apparecchio radiografico elettronico e relativo procedimento per produrre immagini
GB860375A GB1454976A (en) 1974-04-01 1975-02-28 Electron radiographic systems
FR757506379A FR2266201B1 (enrdf_load_stackoverflow) 1974-04-01 1975-02-28
BE153894A BE826157A (fr) 1974-04-01 1975-02-28 Appareil de radiographie et procede de production d'une image electrostatique
JP3863275A JPS5542758B2 (enrdf_load_stackoverflow) 1974-04-01 1975-04-01

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US456532A US3873833A (en) 1974-04-01 1974-04-01 Electron radiographic system with liquid absorber

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US3873833A true US3873833A (en) 1975-03-25

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US456532A Expired - Lifetime US3873833A (en) 1974-04-01 1974-04-01 Electron radiographic system with liquid absorber

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US (1) US3873833A (enrdf_load_stackoverflow)
JP (1) JPS5542758B2 (enrdf_load_stackoverflow)
BE (1) BE826157A (enrdf_load_stackoverflow)
CA (1) CA1030207A (enrdf_load_stackoverflow)
DE (1) DE2507147A1 (enrdf_load_stackoverflow)
FR (1) FR2266201B1 (enrdf_load_stackoverflow)
GB (1) GB1454976A (enrdf_load_stackoverflow)
IT (1) IT1029880B (enrdf_load_stackoverflow)
NL (1) NL7501953A (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3939345A (en) * 1974-12-23 1976-02-17 Xonics, Inc. Liquid crystal imaging of radiograms
US3965352A (en) * 1975-04-24 1976-06-22 Xonics, Inc. X-ray system with electrophoretic imaging
US3988583A (en) * 1974-03-19 1976-10-26 Konishiroku Photo Industry Electrostatic imaging process using X-rays
US4021668A (en) * 1975-03-26 1977-05-03 Agfa-Gevaert, A.G. Ionography imaging chamber
US4119849A (en) * 1975-03-19 1978-10-10 Agfa-Gevaert N.V. Radiography
US4135090A (en) * 1977-05-16 1979-01-16 Degaston Alexis N Liquid ionizing radiation detector
FR2601493A1 (fr) * 1986-07-08 1988-01-15 Thomson Csf Dispositif pour former des images par deplacement de fluides et son utilisation a la realisation de filtres spatiaux a rayons x

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4632642A (en) * 1985-06-24 1986-12-30 Whirlpool Corporation Motor-fan mounting system for canister vacuum cleaner

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3774029A (en) * 1972-06-12 1973-11-20 Xonics Inc Radiographic system with xerographic printing

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS556912B2 (enrdf_load_stackoverflow) * 1973-12-14 1980-02-20

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3774029A (en) * 1972-06-12 1973-11-20 Xonics Inc Radiographic system with xerographic printing

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3988583A (en) * 1974-03-19 1976-10-26 Konishiroku Photo Industry Electrostatic imaging process using X-rays
US3939345A (en) * 1974-12-23 1976-02-17 Xonics, Inc. Liquid crystal imaging of radiograms
US4119849A (en) * 1975-03-19 1978-10-10 Agfa-Gevaert N.V. Radiography
US4021668A (en) * 1975-03-26 1977-05-03 Agfa-Gevaert, A.G. Ionography imaging chamber
US3965352A (en) * 1975-04-24 1976-06-22 Xonics, Inc. X-ray system with electrophoretic imaging
US4135090A (en) * 1977-05-16 1979-01-16 Degaston Alexis N Liquid ionizing radiation detector
FR2601493A1 (fr) * 1986-07-08 1988-01-15 Thomson Csf Dispositif pour former des images par deplacement de fluides et son utilisation a la realisation de filtres spatiaux a rayons x

Also Published As

Publication number Publication date
JPS50137176A (enrdf_load_stackoverflow) 1975-10-31
FR2266201A1 (enrdf_load_stackoverflow) 1975-10-24
CA1030207A (en) 1978-04-25
JPS5542758B2 (enrdf_load_stackoverflow) 1980-11-01
NL7501953A (nl) 1975-10-03
DE2507147A1 (de) 1975-10-09
GB1454976A (en) 1976-11-10
IT1029880B (it) 1979-03-20
FR2266201B1 (enrdf_load_stackoverflow) 1979-02-09
BE826157A (fr) 1975-06-16

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Owner name: ELSCINT IMAGING, INC., MASSACHUSETTS

Free format text: ASSIGNORS DO HEREBY QUITCLAIM, ASSIGN AND TRANSFER THEIR ENTIRE RIGHTS, TITLE AND INTEREST THEY MAYHAVE IN SAID INVENTIN TO ASSIGNEES;ASSIGNORS:XONICS, INC.;XONICS MEDICAL SYSTEMS, INC.;REEL/FRAME:005029/0007

Effective date: 19880718

Owner name: ELSCINT, LIMITED, ILLINOIS

Free format text: ASSIGNORS DO HEREBY QUITCLAIM, ASSIGN AND TRANSFER THEIR ENTIRE RIGHTS, TITLE AND INTEREST THEY MAYHAVE IN SAID INVENTIN TO ASSIGNEES;ASSIGNORS:XONICS, INC.;XONICS MEDICAL SYSTEMS, INC.;REEL/FRAME:005029/0007

Effective date: 19880718

Owner name: ELSCINT, INC., MASSACHUSETTS

Free format text: ASSIGNORS DO HEREBY QUITCLAIM, ASSIGN AND TRANSFER THEIR ENTIRE RIGHTS, TITLE AND INTEREST THEY MAYHAVE IN SAID INVENTIN TO ASSIGNEES;ASSIGNORS:XONICS, INC.;XONICS MEDICAL SYSTEMS, INC.;REEL/FRAME:005029/0007

Effective date: 19880718

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Owner name: XONICS INC., A CA. CORP., ILLINOIS

Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:FIRST CHICAGO INVESTMENT CORPORATION, AS AGENT;REEL/FRAME:005013/0715

Effective date: 19881207