EP0000792B1 - Ecran renforçateur radiographique - Google Patents

Ecran renforçateur radiographique Download PDF

Info

Publication number
EP0000792B1
EP0000792B1 EP78200053A EP78200053A EP0000792B1 EP 0000792 B1 EP0000792 B1 EP 0000792B1 EP 78200053 A EP78200053 A EP 78200053A EP 78200053 A EP78200053 A EP 78200053A EP 0000792 B1 EP0000792 B1 EP 0000792B1
Authority
EP
European Patent Office
Prior art keywords
screen
phosphor
ray image
image intensifying
ray
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
Application number
EP78200053A
Other languages
German (de)
English (en)
Other versions
EP0000792A1 (fr
Inventor
André Roger Suys
Willy Karel Van Landeghem
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.)
Agfa Gevaert NV
Original Assignee
Agfa Gevaert NV
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
Priority claimed from BE2056201A external-priority patent/BE858256A/xx
Application filed by Agfa Gevaert NV filed Critical Agfa Gevaert NV
Publication of EP0000792A1 publication Critical patent/EP0000792A1/fr
Application granted granted Critical
Publication of EP0000792B1 publication Critical patent/EP0000792B1/fr
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/16—X-ray, infrared, or ultraviolet ray processes
    • G03C5/17—X-ray, infrared, or ultraviolet ray processes using screens to intensify X-ray 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
    • G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens

Definitions

  • the present invention relates to improved X-ray image intensifying screens comprising halide containing phosphors and to a process for producing such screens.
  • the commonly used X-ray intensifying screens comprise a support and a layer of fluorescent particles dispersed in a coherent film-forming macromolecular binder medium. Normally a protective coating is applied on top of the fluorescent layer to shield said layer from ambient influences e.g. moisture, air and mechanical abrasion.
  • these protective coatings are composed of cellulose derivatives or synthetic polymers e.g. polyvinyl chloride.
  • Vinyl fluoride polymers and copolymers are described for that purpose in the United States Patent Specification 3,164,719 of Herbert Bauer, issued January 5, 1965.
  • U.S. Patent Specification 3,836,784 the use of vinylidene fluoride polymers in the phosphor layer to counteract moisture has been described.
  • layers comprising cellulose derivatives are somewhat permeable to moisture and therefore more hydrophobic but also more costly synthetic polymers, e.g. polymers containing fluorine atoms, are applied to shield the phosphor layer for moisture.
  • the protection against moisture is required not only to prevent the fluorescent layer from staining but also to prevent water from contacting the phosphor particles since certain phosphors such as the halide-containing phosphors may react with water and loose thereby their fluorescence power.
  • certain phosphors such as the halide-containing phosphors may react with water and loose thereby their fluorescence power.
  • the halide-containing phosphors especially the rare-earth oxyhalide phosphors are relatively easily attacked by water so that an intensifying screen containing these phosphors without protection against moisture becomes rapidly useless.
  • an X-ray image intensifying screen which screen incorporates halide-containing phosphor particles, and wherein the phosphor particles are afforded a high protection against the influence of moisture and loss of fluorescence power.
  • the present invention includes also a process for preparing such screens.
  • the present X-ray image intensifying screen comprises in dispersed form in a supported or self-supporting binder layer:
  • intensification factor of an X-ray image intensifying screen is understood here the quotient of the X-ray exposure required to produce without the use of an intensifying screen an optical density of 1 on a silver halide film, divided by the X-ray exposure required to produce the same density on the same silver halide film by means of said X-ray image intensifying screen, the conditions of the X-ray irradiation and the conditions of development being the same in both cases.
  • the X-ray image intensifying screens commonly used have an intensification factor of at least 4 at 40 kV and of at least 5 at 150 kV.
  • One of the features of the X-ray image intensifying screen according to the present invention is that it comprises halide-containing phosphor particles that are admixed, combined in contact with, or have reacted with one or more organic compounds that are capable of reacting with hydrogen chloride, e.g. hydrogen chloride scavengers, and/or with labile halogen, e.g. labile chlorine or bromine, e.g. one or more of such compounds containing an anion, preferably an anion with oleophilic group or containing a chemical group, preferably a chemical group with oleophilic character, which anion or group can take part in a displacement reaction wherein labile halogen atoms are replaced by said anion or group.
  • hydrogen chloride e.g. hydrogen chloride scavengers
  • labile halogen e.g. labile chlorine or bromine
  • the stabilising compound is a colourless organic compound yielding a preferably colourless reaction product on reacting with hydrogen chloride.
  • a first category of stabilizing compounds for use according to the present invention is formed by organic compounds that contain at least one metal atom and that are hydrogen halide scavengers and/or are capable of replacing labile halogen by an organic group. Within this category or organic compounds very good results have been obtained with organic metal salts and organometallic compounds.
  • a second category of stabilizing compounds for use according to the present invention is described in the co-pending European Patent Application 0 000 961 filed on even date herewith and is formed by organic compounds that contain no metal atoms and that correspond to one of the following general formulae: wherein
  • the groups X may be the same or different chemical groups.
  • Hydrocarbon as used herein is straight-chain, branched-chain or ring-closed saturated or unsaturated hydrocarbon.
  • Stoichiometric amounts of acetyl chloride and of the organic compound to be examined are dissolved in anhydrous benzene and heated herein for 24 h in the presence of a stoichiometric amount of pyridine.
  • the pyridinium chloride formed is separated from the cooled reaction mixture (20°C) by filtering or centrifuging. If pyridinium chloride crystals happen to be contained in the cooled reaction mixture, the compound meets the demand, viz. to be usable as a stabilising agent in the present invention.
  • organic compound to be examined is a primary or secondary amine
  • pyridine may be omitted from the reaction mixture and the chlorides corresponding with these amines form in the reaction.
  • Pyridine is normally used as hydrogen chloride scavenger in alcoholysis (see John H. Billman and Elisabeth S. Cleland in Methods of Synthesis in Organic Chemistry - Edward Brothers, Inc. Ann Arbor, Mich., U.S.A. (1951) 78).
  • the use of pyridine as condensing agent in the preparation of acid anhydrides starting from a carboxylic acid chloride and a carboxylic acid has been described by Wagner and Zook, Synthetic Organic Chemistry - John Wiley and Sons (1953) 558.
  • Suitable organic compounds of this second category are organic compounds according to the above general formulae wherein X is a mercapto group, a primary or secondary amino group, a carboxyl group or a hydroxyl group, which is linked to an aliphatic group or aromatic nucleus.
  • the above mentioned compounds with reactive hydrogen are preferably used in binder compositions containing no splittable halogen atom, thus preferably not in combination with halogenated mono-olefinic polymers or copolymers such as vinyl chloride homopolymers and copolymers.
  • halogenated mono-olefinic polymers or copolymers such as vinyl chloride homopolymers and copolymers.
  • the presence of hydrogen chloride enhances the decomposition of poly(vinyl chloride).
  • organic compounds containing no metal atoms for stabilising the halide-containing phosphors against moisture are organic compounds from which organic compounds with active hydrogen can be formed by hydrolysis, e.g. organic acid anhydrides, esters, amides and nitriles.
  • organic compounds with active hydrogen can be formed by hydrolysis
  • these compounds contain long chain (C 8 C ZO ) hydrocarbon groups as e.g. in hexadecenyl- succinic anhydride, lauric acid methyl ester, stearic acid methyl ester, stearamide and stearonitrile.
  • These compounds are capable of forming with water in situ in the screen composition compounds within the scope of the above general formulae.
  • a preferred optional feature resides in the employment of a compound or mixture of compounds which reduce the adverse effects of moisture on the halide containing phosphor and which protective power satisfies a certain test.
  • This test (hereafter called the "Standard Test") has been devised for the purpose of assessing the level of effectiveness of any selected substance for the protection of the halide-containing phosphor in accordance with the invention and is as follows:
  • moisture-treated screen B would show a fluorescent power of less than 10% relative to that of the non-moisture-treated screen B.
  • a compound or combination of compounds is regarded as satisfying the above Standard Test if the result of the determination in step 6 is that the fluorescent light-emitting power of screen A incorporating that compound or combination of compounds is at least 25% of that of the non-moisture treated screen B.
  • the compound or compounds affording the moisture protection is or are such that when such compound or compounds is or are used in screen A in the Standard Test the fluorescent light-emitting power of screen A is at least 65% are most preferably at least 75% of that of the non-moisture treated screen B.
  • a stabilizing compound belonging to the first category referred to hereinabove which is an organic metal salt, e.g. a metal salt of a carboxylic acid, a so-called metal carboxylate.
  • an organic metal salt e.g. a metal salt of a carboxylic acid, a so-called metal carboxylate.
  • a bi- or tri-valent metal e.g. barium, lead, cadmium or zinc salts.
  • the stabilizing activity of these compounds is assumed to be in their ability to replace labile halogen e.g. chlorine, bromine, or iodine by the acyloxy group -OCOR where R represents an organic group that hydrophobizes the halide-containing phosphor onto which it has been attached.
  • labile halogen e.g. chlorine, bromine, or iodine
  • organic compounds for stabilizing purposes according to the present invention and belonging to the first category referred to are water-insoluble mercaptides e.g. a tin mercaptide corresponding to the following general formula: wherein R is a straight-chain, branched-chain or ring-closed saturated or unsaturated hydrocarbon group, preferably a hydrocarbon group containing at least 4 carbon atoms, e.g. n-butyl.
  • the oleophilic R-S-group is chemically attached to the halide containing phosphor particle containing labile halogen atoms in the form of halide anions and that an exchange of halogen takes place, the mercapto group providing a water-repelling character to the phosphor particle, to which it is chemically bound at its surface.
  • Metal dialkyl mercaptides are prepared e.g. as described by Donald J. Cram and George J. Hammond in their book Organic Chemistry 2nd ed. (1964) McGraw-Hill Book Company Inc. New York, p.552.
  • organotin compounds organoantimony and organobismuth compounds as compounds belonging to the first category of compounds referred to hereinbefore.
  • organotin compounds are known as hydrogen chloride- or hydrogen bromide-scavengers or are known for the slow-down of thermal degradation of poly(vinyl chloride).
  • examples of such compounds are triphenylantimony, triphenylbismuth and tetraphenyltin.
  • a suitable class of organotin compounds corresponds to the following formula: wherein:
  • organotin stabilizing compounds are dialkyltinmercaptides, especially the organotin compounds that are within the scope of one of the following general formulae: wherein
  • Organo-metallic compounds suitable for use according to the invention are further described in the United States Patent Specifications 2,914,506 of Gerry P. Mack, Jackson Heights and Emery Parker, issued November 24, 1959, 2,888,435 of James M. Wallace, Jr. issued May 26, 1959, 2,801,258 of Ernest W. Johnson, issued July 30, 1957, 2,789,102 of Elliott L. Weinberg, 2,789,103 of Elliott L. Weinberg and Louis A. Tomka, 2,789,104 of Hugh E. Ramsden, Elliott L. Weinberg and Louis A. Tomka, 2,789,105 of Louis A. Tomka and Elliott L. Weinberg, all issued April 16, 1957, 2,726,227 and 2,726,254 both of William E. Leistner and Olga H.
  • organo metallic compounds e.g. dibutyltin sulphide
  • suitable organometallic compounds e.g. dibutyltin sulphide
  • thiols are used that contain a hydrocarbon group of at least 6 carbon atoms.
  • Such thiols including aliphatic as well as aromatic representatives have been described by Arthur I. Vogel, Textbook of Practical Organic Chemistry, Longmans 3rd ed. (1959) p.502. Excellent results are obtained with 1-n-dodecane thiol (laurylmercaptan).
  • organic compounds are employed which contain the reactive hydrogen in an amino group, i.e. primary or secondary amines.
  • primary or secondary amines Preferably aliphatic primary or secondary amines are used that contain a hydrocarbon group of at least 8 carbon atoms. Good results are obtained with 1-n-dodecylamine (laurylamine).
  • organic compounds are employed which contain the reactive hydrogen in a carboxyl group.
  • aliphatic carboxylic acids are used that contain a hydrocarbon group of at least 6 carbon atoms. Excellent results are obtained with dodecanoic acid (lauric acid), but aliphatic carboxylic acids containing more than one carboxyl group are considered too, e.g. hexadecylenesuccinic acid, octadecylsuccinic acid, as well as carboxylic acids substituted with a hydroxyl group or a mercapto group, e.g. 12-hydroxystearic acid.
  • organic compounds which contain the reactive hydrogen in a hydroxyl group, which is preferably linked to a hydrocarbon group of at least 6 carbon atoms as e.g. in lauryl alcohol, p-t-amylphenol and isohexadecyl alcohol.
  • the hydrocarbon groups as referred to hereinbefore may comprise substituents that do not enhance the water-solubility of the organic compounds beyond the already given value.
  • Suitable substituents rendering the compounds more hydrophobic are halogen atoms, e.g. fluorine, chlorine and bromine, such as e.g. in p-bromophenol and perfluorocaprylic acid.
  • the preferred stabilizing organic compounds used according to the invention are colourless and upon reaction with the halide-containing phosphor yield a colourless hydrophobic reaction product at the surface of the phosphor particles.
  • halide-containing phosphor particles which are already to some extent protected against loss of fluorescence power by moisture by the above defined substance(s) are admixed with non-hygroscopic halide free fluorescent pigment particles in the amount given.
  • halide free fluorescent pigment particles are preferably such that after having been stored for 64 h under conditions of 80% relative humidity and 25°C, they show a weight increase by uptake of water of at most 0.1%.
  • Halide-free phosphor particles that are suited for use according to the present invention are calcium tungstate, terbium-doped gadolinium oxysulphide (Gd 2 O 2 S:Tb), terbium-doped lanthanum oxysulphide (La 2 O 2 S:Tb) and terbium-doped yttrium oxysulphide (Y 2 O 2 S:Tb).
  • the halide-free phosphor particle emit in the spectral range wherein the halide-containing phosphor emits.
  • blue light emitting calcium tungstate phosphor particles are used in admixture with blue-light emitting rare earth oxyhalide phosphor particles.
  • the invention is particularly concerned with X-ray image intensifying screens including as halide-containing phosphor particles rare-earth oxyhalide phosphor particles containing e.g. as host metal lanthanum and/or gadolinium and one or more other rare-earth metals as activator metal.
  • the activator metal is preferably terbium or thulium.
  • cerium, ytterbium, erbium and/or yttrium are used as activator metal preferably in combination with terbium.
  • Blue-light-emitting phosphors suited for use according to the present invention are within the scope of the following general formula: wherein:
  • the halogen X is preferably present in the range of between the stoichiometric amount and 2.5% deviating thereof.
  • Preferred rare-earth oxyhalide phosphors include ytterbium as impurity and have the following general formula: wherein:
  • rare-earth oxyhalide phosphors contain lanthanum and/or gadolinium as host metal and thulium as activator metal. Such phosphors are described in the United States Patent Specification 3,795,814 and are stated to have a relative speed of more than 3 with respect to calcium tungstate.
  • halide phosphors In rare-earth metal oxyhalide phosphors a part of the halide may be fluoride e.g. as is present in a mixed crystal compound having the following general formula and whose preparation is described in the published German Patent Application 2,329,396: wherein:
  • Suitable rare-earth oxyhalide phosphors contain gadolinium as host metal and cerium as activator metal optionally together with yttrium. These phosphors are described in the published German Patent Application 2,540,344 and correspond to the following general formula: wherein:
  • These phosphors are less hygroscopic than the phosphors according to the first two general formulae mentioned abpve.
  • Terbium-activated lanthanum oxybromide phosphors modified for the elimination of afterglow may also be used. Such phosphors have been described in the published German Patent Application 2,461,260. In these phosphors part of the lanthanum is replaced by lead and/or thallium.
  • halide-containing phosphor particles are e.g. barium fluoride chloride activated with europium (II) described e.g. in French Patent Specification 2,185,667, filed May 23, 1973 by Philips Gloeilampenfabrieken N.V. and cesium iodide phosphors e.g. cesium iodide activated with sodium or thallium (see e.g. United States Patent Specification 3,836,784).
  • the amount of stabilizing compound or mixture of stabilizing compounds suitable for a practically useful increase in stability against moisture of the applied halide-containing phosphor particles may be determined by simple tests.
  • the stabilizing compound(s) is (are) combined by admixture with halide-containing phosphor particles in a chosen phosphor binder layer combination in an amount sufficient to maintain the fluorescent light-emitting power of the layer in a moisture treatment as defined above for screen (A) at a level of at least 75% of the level before said treatment.
  • Effective amounts of stabilizing compound(s), e.g. for use in admixture with lanthanum oxybromide phosphors, are in the range of 0.05 to 10 g per 100 g of phosphor.
  • the non-hygroscopic halide free phosphor particles are admixed with the halide-containing phosphor particles in a ratio by weight that fulfils the requirements of the intensification factor ratio as defined hereinbefore, preferably an intensification factor ratio of 1 :1.
  • X-ray image intensifying screens of the present invention preferably contain in a phosphorbinder layer a mixture of calcium tungstate phosphor particles and rare-earth oxyhalide phosphor particles in a weight ratio range from 60:40 to 90:10 and the phosphor binder layer has a rare-earth oxyhalide coverage between about 100 and about 250 g per sq.m.
  • a preferred ratio by weight of rare-earth oxyhalide phosphor to calcium tungstate phosphor is 1:2 e.g. 1 50 g of rare-earth oxyhalide phosphor and 300 g of calcium tungstate per sq.m.
  • the particle size of the phosphors used in the screen of the present invention is preferably between 0.1 um and about 20,um, more preferably between 1 um and 12 ⁇ m. this range embodying about 80% by volume of the phosphors present in said screen.
  • Suitable binders for use in the preparation of the phosphor layer are, e.g., a cellulose acetate butyrate, polyalkyl (meth)acrylates, e.g. polymethyl methacrylate, a polyvinyl-n-butyral e.g. as described in the United States Patent Specification 3,043,710, a copoly(vinyl acetate/vinyl chloride) and a :copoly(acrylonitrile/butadiene/styrene) or a copoly(vinyl chloride/vinyl acetate/vinyl alcohol) or mixture thereof.
  • the preferred binders are halogen-free polymers or copolymers.
  • the metal organic stabilizing substances having hydrogen chloride-scavenging properties can be used advantageously in combination with any type of binding agent whether it contains halide substituents or not.
  • a minimum amount of binder be employed in the phosphor layer.
  • the thickness of the supported phosphor layer is preferably in the range of 0.05 to 0.5 mm.
  • the coverage of the phosphor mixture is preferably in the range from about 300 to 750 g/sq.m.
  • the halide-containing phosphor particles, the stabilizing substance(s) and the non-hygroscopic halide-free phosphor particles are intimately dispersed in a solution of the binder and then coated upon a support.
  • the halide-containing phosphor particles are first allowed to come in intimate contact with said stabilizing substance(s) in an organic liquid medium e.g. a solution of the binder, to cause the stabilizing substance to contact the halide containing phosphor particles, this can be done by dispersing both- ingredients in the organic liquid medium and thoroughly mixing in a ball mill.
  • the dispersion is admixed with a dispersion of the non-hygroscopic halide-free phosphor particles made in the same way.
  • the mixture if necessary after adjustment of the binder content, can then be coated on the support and dried.
  • halide-containing phosphor particles with the stabilizing substance(s) before dispersing in the binder solution e.g. dispersing the phosphor particles in an organic solution of the stabilizing substance(s) followed by removal of the solvent(s) e.g. separating the phosphor particles from the solution and then drying.
  • the thus treated phosphor particles and the non-hygroscopic halide-free phosphor particles can then be dispersed together in a binder solution or they can be dispersed in separate binder solutions and the dispersions then mixed.
  • the coating of the present phosphor binder layer which is preceded by the thorough dispersing and mixing of the halide-containing phosphor particles and stabilizing compound(s) and non-hygroscopic halide-free phosphor particles in a binder solution, may proceed according to any usual technique, e.g. by spraying or dip-coating. After coating, the solvent(s) of the coating mixture is (are) removed by evaporation, e.g. by drying in an air current of 60°C.
  • An ultrasonic treatment can be applied to improve the packing density and to perform the deaeration of the phosphor-binder combination.
  • the phosphor-binder layer may be calendered to improve the packing density (i.e. the number of grams of phosphor per cm3 of dry coating).
  • Self-supporting screens of this invention can be prepared e.g. by means of "hot-pressing", excluding the use of solvent(s) in the manufacture of the screens.
  • the phosphor-pigment mixture binder composition may be coated on a wide variety of supports, e.g. cardboard and plastic film, e.g. polyethylene terephthalate film.
  • supports e.g. cardboard and plastic film, e.g. polyethylene terephthalate film.
  • the supports used in the fluorescent screens of the present invention may be coated with (a) subbing layer(s) for improving the adherence of the phosphor coating thereto.
  • a light-reflecting layer is provided between the phosphor-containing layer and its support to enhance the exposure of the silver halide emulsion material.
  • Such light-reflecting layer may contain white pigment particles dispersed in a binder, e.g. titanium dioxide particles, or may be made of a vapour-deposited metal layer, e.g. an aluminium layer having a high reflection power for ultraviolet radiation and blue light.
  • screening dye a fluorescent light-absorbing dye, called "screening dye”
  • screening dye includes dyestuffs (i.e. coloured substances in molecularly divided form) as well as pigments.
  • Diffuse radiation reflecting from the support of the fluorescent screen material can be mainly attenuated in an anti-reflection layer containing the screening dyes subjacent to the fluorescent layer.
  • the screening dye does not have to be removed from the fluorescent screen material and may therefore be any dye or pigment absorbing in the emission spectrum of the fluorescent substance(s).
  • black substances such as carbon black particles of an average size of 0.15 to 0.60 ⁇ m incorporated in said anti-reflection layer or the phosphor layer yield quite satisfactory results.
  • a protective coating may be applied preferably having a thickness in the range of 5 to 25 pm and comprising a film-forming polymeric material that is photographically inert towards a silver halide emulsion layer.
  • Polymeric materials suitable for that purpose include e.g. cellulose derivatives (e.g. cellulose nitrate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate), polyamides, polystyrene, polyvinyl acetate, polyvinyl chloride, silicone resins, poly(acrylic ester) and poly(methacrylic ester) resins, and fluorinated hydrocarbon resins, and mixtures of the foregoing materials.
  • cellulose derivatives e.g. cellulose nitrate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate
  • polyamides e.g. cellulose nitrate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate
  • polyamides e.g. cellulose nitrate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate
  • polyamides e.g.
  • binder materials include the following resinous materials: poly(methyl methacrylate), poly(n-butyl methacrylate), poly(isobutyl methacrylate), copolymers of n-butyl methacrylate and isobutyl methacrylate, copolymers of vinylidene fluoride and hexafluoropropylene, copolymers of vinylidene fluoride and trifluorochloroethylene, copolymers of vinylidene fluoride and tetrafluoroethylene, terpolymers of vinylidene fluoride, hexafluoropropylene, and tetrafluoroethylene, and poly(vinylidene fluoride).
  • a protective layer which contains a crosslinked polymer mass obtained by an acid-catalyzed reaction of a polymer or mixture of polymers containing reactive hydrogen atoms and a crosslinking agent, the crosslinking agent being an organic compound containing a plurality of etherified N-methylol groups.
  • the outer face of the screen intended for contact with the photographic silver halide emulsion material may contain a solid particulate material that has a static friction coefficient ( ⁇ ) at room temperature (20°C) of less than 0.50 on steel as described in the published German Patent Application 2,616,093.
  • Antistatic substances can be applied to the screen to reduce the risk of electrical potential differences resulting in sparking.
  • the screens are treated with the "ANTI-STAT" 6 spray, which leaves an odourless transparent antistatic deposit.
  • ANTI-STAT is a trade name of Braun Laboratories Div. Barrett Chemical Co. Inc., Philadelphia, Pa., U.S.A.
  • the fluorescent X-ray image intensifying screens of the present invention will normally be used in conjunction with light-sensitive silver halide materials emulsion-coated on one or both sides of a support.
  • the screen may contain a light-diffusing layer or sheet, which contains numerous discrete light-scattering volumes of a substance or substances distributed at random in a binder medium or partially embedded therein, such volumes having a mean size not larger than 2 ⁇ ⁇ m, said layer or sheet being located so that fluorescent light of said phosphor particles can penetrate therethrough to the outside of said screen.
  • a light-diffusing layer or sheet which contains numerous discrete light-scattering volumes of a substance or substances distributed at random in a binder medium or partially embedded therein, such volumes having a mean size not larger than 2 ⁇ ⁇ m, said layer or sheet being located so that fluorescent light of said phosphor particles can penetrate therethrough to the outside of said screen.
  • terbium-activated lanthanum oxybromide phosphor 100 g of terbium-activated lanthanum oxybromide phosphor, 0.5 g of the stabilizing compound dibutyltin-(A-mercapto propionate), 12.5 g of VINYLITE VAGH (registered trade mark in the United Kingdom of Union Carbide and Carbon Corp., New York, USA) for a copoly(vinyl chloride/vinyl acetate/vinyl alcohol) (91/3/6 by weight) dissolved in 48 g of methyl ethyl ketone were ball-milled to a fineness of grind corresponding with 7 NS Hegman Fineness-of-Grind measured with the Hegman gauge as specified in ASTM D1210, whereupon the dispersion obtained was filtered and after deaeration coated onto a baryta-coated paper of 290 g per sq.m at a coverage of 150 g of phosphor per sq.m to
  • the phosphor layer was overcoated with a protective coating from a 7.5% solution in ethyleneglycol monomethyl ether of cellulose acetate butyrate having a degree of substitution (DS) of acetyl 1.31 and a DS of butyryl of 1.51.
  • the dried protective coating had a coating weight of 10 g per sq.m.
  • the X-ray image intensifying screen Q was manufactured as described for screen P with the difference that the stabilizing compound was omitted from the composition of the screen.
  • the X-ray image intensifying screen R was manufactured as described for screen P with the difference that, before coating, the oxybromide phosphor dispersion was mixed with a calcium tungstate phosphor dispersion which was prepared as described for the lanthanum oxybromide phosphor dispersion of screen P with the only difference that the oxybromide phosphor was replaced by a same amount of calcium tungstate.
  • the calcium tungstate phosphor dispersion was added in an amount such that the final dispersion contained the oxybromide phosphor and calcium tungstate phosphor in a ratio of 1:2.
  • the phosphor mixture dispersion was coated on the same support as described for screen P at a phosphor mixture coverage per sq.m of 150 g of terbium-activated lanthanum oxybromide phosphor and 300 g of calcium tungstate.
  • the ratio of the intensification factors of screens P and R was 1:1.
  • This intensifying screen was prepared as screen P of example 1, with the difference that 0.5 g of lauryl alcohol was used as stabiliser.
  • This intensifying screen was prepared as screen Q of example 1, and differs from screen K in that the stabiliser was omitted from the screen composition.
  • the intensifying screen was prepared as screen K, with the difference that before the application of the oxybromide phosphor dispersion the latter was mixed with a calcium tungstate phosphor dispersion which was prepared as described for the lanthanum oxybromide phosphor dispersion of screen K, with the only difference that the oxybromide phosphor was replaced by an equal weight of calcium tungstate. Then the prepared calcium tungstate phosphor dispersion was added in such an amount to the lanthanum oxybromide dispersion that the final dispersion contained the oxybromide phosphor and the calcium tungstate phosphor in a ratio by weight of 1:2.
  • the phosphor mixture dispersion was coated on the same support as described for screen K at a phosphor mixture coverage of 150 g of terbium-activated lanthanum oxybromide phosphor and 300 g of calcium tungstate per sq.m.
  • the ratio of the intensification factors of screens K and M was 1:1.
  • Analogous results were obtained by replacing 0.5 g of lauryl alcohol in the compositions of screens K and M by a same amount of laurylmercaptan and lauric acid respectively.
  • a usable result was obtained by replacing in the compositions of screens K and M the lauryl alcohol by a same amount of 1-n-dodecylamine.
  • the photographic material used in the contact exposure with the screen strips was a CURIX RP-1 film (CURIX is a registered trade mark of AGFA-GEVAERT N.V. for a medical X-ray film).
  • the X-ray exposure proceeded for all the test strips at 80 kV tube voltage.
  • the silver halide film exposed in adjacent area with the fluorescent light of a pair of water-vapour-treated and non-water-vapour-treated screen strips was subjected to development in the Agfa-Gevaert's hardening developer G138 which contains hydroquinone and 1-phenyl-3-pyrazolidinone as developing agents and glutardialdehyde as hardening agent.
  • the screens were prepared as follows:
  • a calcium tungstate phosphor dispersion was prepared in the same way as the above lanthanum oxybromide phosphor dispersion and the calcium tungstate phosphor dispersion added in such an amount to the lanthanum oxybromide phosphor dispersion that the final dispersion contained the lanthanum oxybromide phosphor and calcium tungstate phosphor in a ratio of 1:2.
  • the phosphor mixture dispersion thus obtained was coated onto a baryta-coated paper of 290 g per sq.m at a coverage of about 450 g of phosphor per sq.m.
  • the phosphor layer was overcoated with a protective coating from a 7.5% solution in ethylene glycol monomethyl ether of cellulose acetate butyrate having a degree of substitution (LS) of acetyl 1.31 and a Ds of butyrylrpf 1.51.
  • the dried protective coating had a coating weight of 10 g per sq.m.
  • Preferred stabilizing agents for use according to the present invention are those that in the circumstances of the above test in Example 3 wherein said phosphor combination is used in an intensifying screen protect the fluorescence power of that screen to such a degree that the optical density value obtained with the water-vapour-treated screen after the 240 min treatment is not lowered by a value larger than 0.6, most preferably not larger than 0.3, with respect to the optical density value obtained with the non-water-vapour-treated screen.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Inorganic Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Conversion Of X-Rays Into Visible Images (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)

Claims (10)

1. Ecran renforçateur d'images radiographiques comprenant, sous une forme dispersée dans une couche de liant déposée sur un support ou autoportante:
1) des particules d'une substance luminescente contenant un halogénure qui sont mélangées avec, qui sont combinées en contact avec ou qui ont réagi avec un ou plusieurs composés organiques de telle sorte que le pouvoir fluorescent de ces particules ait moins tendance à être réduit par l'humidité, ces composés étant capables de réagir avec le chlorure d'hydrogène et/ou avec un halogène labile ou encore, ces composés pouvant acquérir cette aptitude in situ après hydrolyse, et
2) des particules non hygroscopiques d'une substance luminescente exempte d'halogénure, le rapport pondéral de (1) à (2) étant tel que le rapport entre le facteur de renforcement de cet écran et le facteur de renforcement d'un écran identique ne contenant toutefois pas des particules non hygroscopiques d'une substance luminescente (2) ne soit pas inférieur à 1:4, le facteur de renforcement étant le quotient de l'exposition radiographique requise pour produire, sans utiliser un écran renforçateur, une densité optique de 1 sur une pellicule à l'halogénure d'argent, divisé par l'exposition radiographique requise pour produire la même densité sur la même pellicule à l'halogénure d'argent au moyen de cet écran renforçateur d'images radiographiques, les conditions de l'irradiation radiographique et les conditions de développement étant les mêmes dans les deux cas.
2. Ecran renforçateur d'images radiographiques suivant la revendication 1, caractérisé en ce que le composé organique est un sel de métal organique ou un composé organométallique.
3. Ecran renforçateur d'images radiographiques suivant la revendication 1, caractérisé en ce que le composé organique est un composé organique ne contenant pas d'atome de métal, il a, à 15°C, une solubilité ne dépassant pas 5 g dans 100 ml d'eau et il répond à une des formules générales suivantes:
Figure imgb0019
où
R représente un groupe organique monovalent,
R1 représente un groupe organique bivalent, à condition que ces groupes ne contiennent pas un atome d'hydrogène réactif tel que celui contenu dans X, et
X représente un groupe contenant de l'hydrogène réactif avec lequel, par réaction avec le chlorure d'acétyle, ce composé est capable d'en séparer du chlore sous forme de chlorure d'hydrogène dans les conditions de l'essai A ci-après:
on dissout des quantités stoechiométriques de chlorure d'acétyle et du composé organique à examiner dans du benzène anhydre et on les y chauffe pendant 24 heures en présence d'une quantité stoechiométrique de pyridine pour former, avec celle-ci et lors de la séparation du chlorure d'hydrogène, du chlorure de pyridinium qui est séparé, à 20°C, du mélange réactionnel refroidi, par filtration ou par centrifugation.
4. Ecran renforçateur d'images radiographiques suivant l'une quelconque des revendications précédentes, caractérisé en ce qu'il comprend des particules d'une substance luminescente contenant un halogénure, qui sont mélangées avec, qui sont combinées en contact avec ou qui ont réagi avec au moins un composé organique de ce type, ce composé étant capable, lorsqu'il est utilisé dans les conditions de l'essai ci-après, de maintenir le pouvoir d'émission de lumière fluorescente de la substance luminescente d'essai à un niveau d'au moins 25% de son pouvoir initial d'émission de lumière fluorescente, cet essai comprenant les étapes suivantes:
(1) la formation des écrans renforçateurs d'images radiographiques (A) et (B),
(2) un traitement de l'écran (A) à l'humidité en appliquant, sur la couche de substance luminescente de cet écran, un morceau circulaire humide de papier filtrant pesant 1,355 g à sec, ayant un diamètre de 15 cm et une teneur en eau de 3,100 g, puis en enfermant, à l'abri de l'air, l'écran (A) sur lequel est appliqué le papier filtrant dans un sac en polyéthylène, en maintenant ce sac pendant 64 heures à 60°C dans une étuve ventilée, puis en retirant 1 écran du sac, en enlevant le papier filtrant et en séchant l'écran à l'air pendant 30 minutes à 80°C,
(3) une exposition radiographique des écrans (A) et (B) en contact avec des zones distinctes d'un matériau photographique comportant une émulsion à l'halogénure d'argent et ensuite, le développement de ce matériau,
(4) le mesure des densités spectrales obtenues dans les zones de ce matériau qui ont été exposées en contact avec les écrans (A) et (B), et
(5) le calcul de la perte réelle du pouvoir d'émission de lumière fluorescente de l'écran (A) traité à l'humidité comparativement avec l'écran (B) d'après les résultats obtenus à l'étape (4) à propos de la densité spectrale,
la formation de l'écran renforçateur d'images radiographiques (A) se déroulant de la manière suivante:
dans un broyeur à boulets, on broie 100 g d'une substance luminescente d'oxybromure de lanthane activé au terbium, 0,5 g du composé devant être soumis à l'essai, 12,5 g de poly(vinyl-n-butyral) contenant 12% en poids de motifs d'alcool vinylique non acétalisé et ayant un poids moléculaire moyen de 50.000, ainsi que 48 g d'éther monométhylique d'éthylène-glycol jusqu'à une finesse de broyage correspondant à 7 NS Hegman, mesuré avec la jauge de Hegman selon les spécifications de la norme ASTM D1210, après quoi on filtre la dispersion ainsi obtenue et, après désaération, on la coule sur un papier baryté de 290 g/m2 à raison de 500 g/m2 pour former l'écran renforçateur radiographique A,
la formation de l'écran renforçateur d'images radiographiques (B) se déroulant comme décrit pour l'écran (A), avec cette différence que la substance devant être soumise à l'essai est omise dans la composition de l'écran,
le traitement de l'écran (A) à l'humidité se déroulant en recouvrant correctement le revêtement de substance luminescente de l'écran (A) d'un morceau circulaire humide de papier filtrant pesant 1,355 g à sec et ayant un diamètre de 15 cm, ainsi qu'une teneur en eau de 3,100 g, puis en enfermant, à l'abri de l'air, l'écran ainsi recouvert (A) dans un sac en polyéthylène et en maintenant l'écran ainsi recouvert et emballé (A) à 60°C pendant 64 heures dans une étuve ventilée, puis en retirant cet écran (A) du sac et, après enlèvement du papier filtrant, en procédant à un séchage à l'air à 80°C pendant 30 minutes,
l'exposition radiographique de l'écran ainsi traité (A) et de l'écran non traité (B) se déroulant alors que les écrans pourvus du revêtement de substance luminescente sont en contact avec la face sur laquelle est appliquée une couche d'émulsion à-l'halogénure d'argent d'un même matériau photographique d'émulsion à l'halogénure d'argent comportant un support transparent, l'exposition radiographique et le développement ultérieur du magériau à l'halogénure d'argent se déroulant de telle sorte qu'avec l'écran (B), on obtienne une densité spectrale d'au moins 1,00 au-delà du voile inhérent dans la zone du matériau à l'halogénure d'argent qui est en contact avec l'écran (B); le matériau à l'halogénure d'argent et le développement sont conçus de telle sorte qu'après accroissement progressif des expositions avec l'écran (B), on obtienne une image argentique dont la courbe de la densité vis-à-vis du log d'exposition a une valeur gamma de 3;
le mesure des densités spectrales de transmission DA et DB se déroulant dans les zones du matériau développé d'émulsion à l'halogénure d'argent qui, au cours de l'exposition, ont été en contact avec les écrans (A) et (B) respectivement;
le calcul de la perte réelle du pouvoir d'émission de luminère fluorescente le écran (A) traité à l'humidité comparativement à l'écran (B) se déroulant sur la base des résultats de densité spectrale DA et DB ainsi que sur la base de la valeur gamma de 3.
5. Ecran renforçateur d'images radiographiques suivant la revendication 2, caractérisé en ce que le sel organique d'un métal est un carboxylate d'un métal.
6. Ecran renforçateur d'images radiographiques suivant la revendication 2, caractérisé en ce que le composé organométallique répond à la formule suivante:
Figure imgb0020
dans laquelle
R représente un group d'hydrocarbure saturé ou insaturé, à chaîne droite, à chaîne ramifiée ou cyclisé,
X représente 1 à 3 substituants électronégatifs, et
m est égal à 1, 2 ou 3, étant exclu que X représente trois, deux ou un atome(s) d'halogène(s) lorsque m est égal à 1, 2 ou 3 respectivement.
7. Ecran renforçateur d'images radiographiques suivant la revendication 2, caractérisé en ce que le composé organométallique est un mercaptide d'étain-dialkyle ou un composé organométallique répondant à l'une ou l'autre des formules générales suivantes:
Figure imgb0021
où
R' représente un groupe alkyle ou un groupe alkyle substitué,
chacun des radicaux X1 et X2, qui peuvent être identiques ou différents, représente ―O―CO―R2 ou -S-R3 où R2 est un groupe alkyle ou un groupe alkyle substitué, et R3 est un groupe alkyle, y compris un groupe alkyle substitué,
Figure imgb0022
R1 a la même signification que celle définie ci-dessus, et
Y représente un groupe alkylène.
8. Ecran renforçateur d'images radiographiques suivant la revendication 7, caractérisé en ce que ce composé est le maléate d'étain-dibutyle, le lauryl-mercaptide d'étain-dibutyle, le S,S'-bis-(n-octyl- mercapto-acétate) d'étain-dibutyle, le S,S'-bis-(isooctylmercapto-acétate) d'étain-di-(n-octyle) ou le f3-mercaptopropionate d'étain-dibutyle.
9. Ecran renforçateur d'images radiographiques suivant l'une quelconque des revendications précédentes, caractérisé en ce que les particules de substance luminescente qui sont exemptes d'halogénure et non hydroscopiques, sont constituées de tungstate de calcium, d'oxysulfure de gadolinium dopé au terbium, d'oxysulfure de lanthane dopé au terbium ou d'oxysulfure d'yttrium dopé au terbium.
10. Ecran renforçateur d'images radiographiques suivant l'une quelconque des revendications précédentes, caractérisé en ce que cet écran comprend des particules d'une substance luminescente d'un oxyhalogénure de terre rare contenant, comme métal hôte, du lanthane et/ou du gadolinium et, comme métal activateur, un ou plusieurs autres métaux de terres rares.
EP78200053A 1977-07-20 1978-06-20 Ecran renforçateur radiographique Expired EP0000792B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB3049777 1977-07-20
GB3049777 1977-07-20
BE2056201 1977-08-31
BE2056201A BE858256A (nl) 1977-08-31 1977-08-31 Fluorescerende materialen voor gebruik in de rontgenfotografie

Publications (2)

Publication Number Publication Date
EP0000792A1 EP0000792A1 (fr) 1979-02-21
EP0000792B1 true EP0000792B1 (fr) 1983-02-09

Family

ID=25661720

Family Applications (1)

Application Number Title Priority Date Filing Date
EP78200053A Expired EP0000792B1 (fr) 1977-07-20 1978-06-20 Ecran renforçateur radiographique

Country Status (6)

Country Link
US (1) US4180740A (fr)
EP (1) EP0000792B1 (fr)
JP (1) JPS6048027B2 (fr)
CA (1) CA1116389A (fr)
DE (1) DE2862172D1 (fr)
FR (1) FR2398326B1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4316092A (en) * 1976-12-13 1982-02-16 General Electric Company X-Ray image converters utilizing rare earth admixtures
CH632344A5 (de) * 1978-02-22 1982-09-30 Ciba Geigy Ag Mittel zur szintillationszaehlung.
DE2927428C3 (de) * 1979-07-06 1982-05-19 Siemens AG, 1000 Berlin und 8000 München Leuchtstoff
JPH0690317B2 (ja) * 1991-01-28 1994-11-14 富士写真フイルム株式会社 放射線増感スクリーン
US6399397B1 (en) * 1992-09-14 2002-06-04 Sri International Up-converting reporters for biological and other assays using laser excitation techniques
US5646412A (en) * 1995-07-19 1997-07-08 Eastman Kodak Company Coated radiographic phosphors and radiographic phosphor panels
JP3705664B2 (ja) * 1996-12-16 2005-10-12 富士写真フイルム株式会社 放射線像変換パネル
JP2004285160A (ja) * 2003-03-20 2004-10-14 Konica Minolta Holdings Inc 輝尽性蛍光体、その製造方法及び放射線画像変換パネル
DE102014217580A1 (de) * 2014-09-03 2016-03-03 Siemens Aktiengesellschaft Szintillatorplatte und Verfahren zu deren Herstellung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0000961A1 (fr) * 1977-08-31 1979-03-07 Agfa-Gevaert N.V. Matières fluorescentes et leur utilisation en photographie radiographique.
EP0003151A1 (fr) * 1978-01-16 1979-07-25 Agfa-Gevaert N.V. Ecrans renforçateurs d'images de rayons-X, comprenant des particules luminescentes d'oxyhalogénures de terres rares

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1271542B (de) * 1961-08-04 1968-06-27 Siemens Ag Leuchtschirm
DE1236935B (de) * 1961-10-17 1967-03-16 Agfa Ag Transparente photographische Verstaerkerfolien
US3649329A (en) * 1969-06-30 1972-03-14 Sylvania Electric Prod Phosphor coating for arc discharge lamps
DE2304150A1 (de) * 1973-01-29 1974-08-01 Siemens Ag Fluoreszenzschirm fuer roentgenzwecke
GB1501267A (en) * 1975-04-04 1978-02-15 Ciba Geigy Ag X-ray screens
US4054799A (en) * 1975-10-23 1977-10-18 Gte Sylvania Incorporated X-ray phosphor composition and x-ray intensifying screen employing same
JPS5919159B2 (ja) * 1975-11-14 1984-05-02 株式会社東芝 Ｘ センケイコウヒヨウジバン
FR2344618A1 (fr) * 1976-06-28 1977-10-14 Agfa Gevaert Perfectionnements relatifs a des ecrans de transformation de radiations
US4109152A (en) * 1976-08-13 1978-08-22 Dai Nippon Toryo Co., Ltd. X-ray intensifying screens

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0000961A1 (fr) * 1977-08-31 1979-03-07 Agfa-Gevaert N.V. Matières fluorescentes et leur utilisation en photographie radiographique.
EP0003151A1 (fr) * 1978-01-16 1979-07-25 Agfa-Gevaert N.V. Ecrans renforçateurs d'images de rayons-X, comprenant des particules luminescentes d'oxyhalogénures de terres rares

Also Published As

Publication number Publication date
CA1116389A (fr) 1982-01-19
FR2398326A1 (fr) 1979-02-16
US4180740A (en) 1979-12-25
JPS6048027B2 (ja) 1985-10-24
DE2862172D1 (en) 1983-03-17
JPS5422191A (en) 1979-02-19
EP0000792A1 (fr) 1979-02-21
FR2398326B1 (fr) 1980-06-20

Similar Documents

Publication Publication Date Title
US5023014A (en) Phosphor
US4138361A (en) Radiation-conversion screens
EP0003151B1 (fr) Ecrans renforçateurs d'images de rayons-X, comprenant des particules luminescentes d'oxyhalogénures de terres rares
JP3532636B2 (ja) バインダー相溶性オキソ硫黄安定剤を有する放射線写真蛍りん光体パネル及び蛍りん光体パネルの製造方法
EP0028521B1 (fr) Ecrans à luminescence verte pour amplifier les images obtenues par rayons X
EP0000792B1 (fr) Ecran renforçateur radiographique
EP0654794B1 (fr) Panneau d'enregistrement d'image obtenue par rayonnement recouvert d'une couche protectrice et méthode de fabrication de ce panneau
EP0103874A2 (fr) Couche de recouvrement flexible, ne tachant pas, pour écran renforçateur de rayons X
US4149083A (en) Radiographic intensifying screens
US4205116A (en) Fluorscent X-ray image intensifying screen
EP0249660A1 (fr) Procédé de conversion de rayons X
US4822696A (en) Process for the conversion of X-rays
EP0103302B1 (fr) Ecran renforçateur radiographique
EP0000961B1 (fr) Matières fluorescentes et leur utilisation en photographie radiographique.
US4900641A (en) Radiographic intensifying screen
Suys et al. Luminescent composition for radiation-conversion screens
EP0148507A2 (fr) Matériau luminescent et écran pour l'enregistrement d'une image obtenue par rayonnement utilisant celui-ci
EP0146970B1 (fr) Utilisation d'un materiau luminescent contenant Ba, Ca, F et halogène activé avec emopium bivalent pour l'enregistrement et la reproduction d'une image obtenue par rayonnement.
JPH0631908B2 (ja) シランカツプリング剤を含有する放射線画像変換パネル
US5585202A (en) Radiographic phosphor panel having organolead reducing agents
EP0654796A1 (fr) Panneau d'enregistrement pour image obtenue par rayonnement, stabilisé par un pigment
JPH0631893B2 (ja) 放射線増感紙
van Landeghem et al. Improved fluorescent X-ray image intensifying screen
Bossomaier et al. X-ray intensifying screens
JPH0631916B2 (ja) 放射線像変換パネル

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): BE DE GB

17P Request for examination filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): BE DE GB

REF Corresponds to:

Ref document number: 2862172

Country of ref document: DE

Date of ref document: 19830317

REG Reference to a national code

Ref country code: GB

Ref legal event code: 746

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19950413

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19960523

Year of fee payment: 19

Ref country code: DE

Payment date: 19960523

Year of fee payment: 19

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Effective date: 19960630

BERE Be: lapsed

Owner name: AGFA-GEVAERT N.V.

Effective date: 19960630

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19970620

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19970620

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980303

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT