EP0102010B1 - Couche de conversion pour une image obtenue par rayonnement - Google Patents

Couche de conversion pour une image obtenue par rayonnement Download PDF

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Publication number
EP0102010B1
EP0102010B1 EP19830107976 EP83107976A EP0102010B1 EP 0102010 B1 EP0102010 B1 EP 0102010B1 EP 19830107976 EP19830107976 EP 19830107976 EP 83107976 A EP83107976 A EP 83107976A EP 0102010 B1 EP0102010 B1 EP 0102010B1
Authority
EP
European Patent Office
Prior art keywords
radiation image
fluorescent sheet
protective layer
fluorescent
sheet
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
EP19830107976
Other languages
German (de)
English (en)
Other versions
EP0102010A3 (en
EP0102010A2 (fr
Inventor
Michio Tanaka
Noboru Kotera
Yoshitsugu Nishimura
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.)
Kasei Optonix Ltd
Original Assignee
Kasei Optonix Ltd
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
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Application filed by Kasei Optonix Ltd filed Critical Kasei Optonix Ltd
Publication of EP0102010A2 publication Critical patent/EP0102010A2/fr
Publication of EP0102010A3 publication Critical patent/EP0102010A3/en
Application granted granted Critical
Publication of EP0102010B1 publication Critical patent/EP0102010B1/fr
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Classifications

    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens
    • 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

Definitions

  • the present invention relates to a radiation image conversion sheet (hereinafter referred to as a "fluorescent sheet”) wherein a stimulable phosphor is used. More particularly, the present invention relates to a fluorescent sheet which is provided with a protective layer made of an organic film having a certain specific percentage haze and which scarcely presents undesirable shadows on a radiation image.
  • certain phosphors When subjected to a radiation such as X-ray, y-ray, a-ray or a-ray, certain phosphors, i.e. stimulable phosphors, are capable of storing the radiation energy, and subsequently when irradiated by an electromagnetic wave such as visible light or an infrared ray or when stimulated by heat, they emit fluorescent light.
  • a radiation such as X-ray, y-ray, a-ray or a-ray
  • an electromagnetic wave such as visible light or an infrared ray or when stimulated by heat
  • a radiation image conversion method is being developed for practical use wherein a radiation passing through an object is irradiated to a fluorescent sheet (which may take a form of a plate or drum, and which will be generally referred to as a "fluorescent sheet" in this specification) which comprises a phosphor layer formed on a support such as a paper sheet, a plastic sheet or a thin metal sheet and composed of such a stimulable phosphor, to store a latent radiation image of the object in the fluorescent sheet, and later on the fluorescent sheet is stimulated to emit light by irradiating an electromagnetic wave such as visible light or an infrared ray to the phosphor layer of the fluorescent sheet or by heating the fluorescent layer, whereupon the emitted fluorescence is detected to read out the radiation image of the object stored in and memorized by the fluorescent sheet (e.g. U.S. Patents No. 3,859,527 and No. 4,258,264).
  • a fluorescent sheet which may take a form of a plate or drum, and which will
  • a transparent protective layer made of an organic film is provided on the phosphor layer of the fluorescent sheet for the purpose of improving the physical and chemical durability by preventing the wearing or falling off of the phosphor layer or by preventing the reaction with moisture or a chemical substance.
  • a light source having good coherency to the fluorescent sheet having an organic film as a protective layer such as a laser beam
  • minute lines as fine as from 0.01 to 0.1 pm or local irregularities in thickness will be reproduced as shadows (hereinafter referred to as "radiation image shadows") on the reproduced radiation image, which hinder the interpretation of the image.
  • radiation image shadows it is industrially extremely uneconomical to select organic films having a uniform thickness in order to avoid such a disadvantage.
  • a stimulating ray having good coherency such as a laser beam
  • the present inventors have found that there is an interrelation between the percentage haze of the organic film used as the protective layer of the fluorescent sheet and the appearance of the radiation image shadows, and that when an organic film having a certain specific percentage haze is used as the protective layer, it is possible to obtain a fluorescent sheet which scarcely gives rise to radiation image shadows.
  • the present invention provides a fluorescent sheet comprising a phosphor layer formed on a support and composed of a binder and stimulable phosphor particles dispersed in the binder, and a protective layer formed on the phosphor layer, wherein the protective layer is made of an organic film having a percentage haze of from 5 to 40%.
  • a stimulable phosphor and a binder are mixed in a proper solvent to prepare a coating dispersion of the phosphor. Then, the coating dispersion may directly be applied onto a support and dried to form a phosphor layer. Alternatively, the coating dispersion of the phosphor may be coated on a flat substrate and dried to form a fluorescent layer, which is then peeled off from the substrate and bonded to a support to form a phosphor layer on the support. Then, a protective layer made of an organic film is bonded to the surface of this phosphor layer. Alternatively, a coating solution of a resin which is capable of forming an organic film when dried, may be applied to the surface of the phosphor layer and dried to form a protective layer of the organic film on the surface of the phosphor layer.
  • an organic film for instance, a polyester film of e.g. polyethylene terephthalate, a polymethacrylate film, a nitrocellulose film or a cellulose acetate film, which has a hazy appearance and a percentage haze of from 5 to 40% as measured by the method described in ASTM D-1003.
  • a polyester film particularly a polyethylene terephthalate film, since it has superior mechanical strength and chemical resistance, and its shrinking property is small.
  • the thickness of the organic film to be used is not critical. However, it is usually preferred to employ a film having a thickness of from 5 to 25 pm.
  • the percentage haze of the protective layer varies depending upon the type of the organic film, the degree of polymerization thereof or the impurities contained therein. Further, even when the same type of an organic film is used, the percentage haze varies depending upon the thickness of the film. Furthermore, the percentage haze may be varied by the application of surface treatment such as uniform matting treatment to the surface of the organic film. Accordingly, it is possible to provide a protective layer made of an organic film having a desired percentage haze by properly selecting the type and the thickness of the organic film or by applying a proper surface treatment. However, if the percentage haze of the organic film to be used is less than 5%, the fluorescent sheet thereby obtainable will have little effectiveness for the elimination of shadows from the radiation image.
  • the percentage haze of the organic film tends to decrease although the shadows on the radiation image decrease. If the percentage haze exceeds 40%, the sensitivity tends to decrease by at least about 10% of the sensitivity of the conventional fluorescent sheet. Therefore, from the practical point of view, the percentage haze should be at most 40%. It is particularly preferred to use an organic film having a percentage haze of from 8 to 25%.
  • the stimulable phosphor there may be used a phosphor such as SrS:Ce, Eu; SrS:Eu, Sm; Zns:Cu, Pb; (Zn, Cd) S:Mn, X (where X is halogen); LnOX:A (where Ln is at least one of La, Y, Gd and Lu, X is at least one of CI and Br, and A is at least one of Ce and Tb); or (Ba 1 - x , M" X ) FX:Ln (where M" is at least one of Mg, Ca, Sr, Zn and Cd, X is at least one of Cl, Br and I, Ln is at least one of Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb and Er, and x is 0 ⁇ 0.6),
  • the binder resin there may be used nitrocellulose, a vinyl chloride-vinyl acetate copolymer or polyvinyl butyral.
  • a plastic film such as a cellulose acetate film, a polyester film, a polyimide film or a polycarbonate film, a paper sheet, a glass plate or a thin metal sheet such as an aluminum sheet, may be used. If required, a light absorptive layer or a light reflective layer may be provided on the surface of the support.
  • the shadows on the radiation image can be substantially minimized although the sensitivity tends to be somewhat lower than the case where the conventional fluorescent sheet is used.
  • a BaFBr:Eu" phosphor i.e. a stimulable phosphor
  • nitrocellulose i.e. a binder
  • this coating dispersion was uniformly coated on a horizontally placed black polyethylene terephthalate film (i.e. a support) having a thickness of 250 pm by means of a knife coater and dried to form a phosphor layer having a thickness of about 300 pm.
  • Fluorescent Sheet R was prepared as a Comparative Example in the same manner as the preparation of Fluorescent Sheet A except that a polyethylene terephthalate film having a thickness of 12 11m and a percentage haze of 2.5% (Lumirror Type S-10, manufactured by Toray Industries Inc.) was used as the protective layer.
  • Fluorescent Sheets A and R With respect to Fluorescent Sheets A and R, the radiation images of the same object obtained by using a He-Ne laser beam as the stimulating ray (i.e. the images of the respective radiation image information reproduced on photographic films when the respective flourescent sheets were - stimulated by the He-Ne laser beam) were compared.
  • the sensitivity of Fluorescent Sheet A was about 95% of the sensitivity of Fluorescent Sheet R.
  • the radiation image obtained by Fluorescent Sheet R contained a number of distinct undesirable shadow lines observable by naked eyes, whereas the corresponding image obtained by Fluorescent Sheet A had no substantial shadow lines as observed on the image obtained by Fluorescent Sheet R.
  • Fluorescent Sheet B was prepared in the same manner as the preparation of Fluorescent Sheet A of Example 1 except that a polyethylene terephthalate film having a thickness of 12 ⁇ m and a percentage haze of 22% (polyester film type E1512, manufactured by Toyobo Co., Ltd.) was used as the protective layer.
  • a polyethylene terephthalate film having a thickness of 12 ⁇ m and a percentage haze of 22% polyester film type E1512, manufactured by Toyobo Co., Ltd.
  • Fluorescent Sheet B and the above-mentioned Fluorescent Sheet R prepared for the purpose of comparison the radiation images of the same object obtained by using a He-Ne laser beam as the stimulating ray (i.e. the images of the radiation image information reproduced on photographic films when the respective fluorescent sheets were stimulated by the He-Ne laser beam) were compared.
  • the sensitivity of Fluorescent Sheet B was about 90% of that of Fluorescent Sheet R.
  • the radiation image obtained by Fluorescent Sheet R contained a number of distinct shadow lines observable by naked eyes, whereas the corresponding image obtained by Fluorescent Sheet B had no shadow lines as observed on the image obtained by Fluorescent Sheet R.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Conversion Of X-Rays Into Visible Images (AREA)
  • Radiography Using Non-Light Waves (AREA)

Claims (4)

1. Feuille de conversion des images radiographiques, comprenant une couche fluorescente formée sur un support et composée d'un liant et de particules de substance fluorescente activable dispersées dans le liant, et une couche protectrice formée sur la couche fluorescente, caractérisée par le fait que la couche protectrice est constituée par un film organique présentant un pourcentage de trouble allant de 5 à 40%.
2. Feuille de conversion des images radiographiques selon la revendication 1, dans laquelle le pourcentage de trouble du film organique va de 8 à 25%.
3. Feuille de conversion des images radiographiques selon la revendication 1, dans laquelle la couche protectrice présente une épaisseur allant de 5 à 25 pm.
4. Feuille de conversion des images radiographiques selon la revendication 1 ou 3, dans laquelle la couche protectrice est constituée par un film de poly(éthylène téréphtalate).
EP19830107976 1982-08-19 1983-08-11 Couche de conversion pour une image obtenue par rayonnement Expired EP0102010B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP14264782A JPS5932900A (ja) 1982-08-19 1982-08-19 放射線像変換シ−ト
JP142647/82 1982-08-19

Publications (3)

Publication Number Publication Date
EP0102010A2 EP0102010A2 (fr) 1984-03-07
EP0102010A3 EP0102010A3 (en) 1984-07-25
EP0102010B1 true EP0102010B1 (fr) 1987-04-15

Family

ID=15320213

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19830107976 Expired EP0102010B1 (fr) 1982-08-19 1983-08-11 Couche de conversion pour une image obtenue par rayonnement

Country Status (3)

Country Link
EP (1) EP0102010B1 (fr)
JP (1) JPS5932900A (fr)
DE (1) DE3371009D1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5942500A (ja) * 1982-09-01 1984-03-09 富士写真フイルム株式会社 放射線像変換パネル
JPS6195351A (ja) * 1984-10-17 1986-05-14 Kasei Optonix Co Ltd 増感紙
JPS6215498A (ja) * 1985-07-12 1987-01-23 コニカ株式会社 放射線画像変換パネル
JP2843998B2 (ja) * 1988-06-21 1999-01-06 コニカ株式会社 放射線画像変換パネル
JPH09311200A (ja) * 1996-05-23 1997-12-02 Fuji Photo Film Co Ltd 放射線像変換パネル及び放射線像読取方法
JP2010025780A (ja) * 2008-07-22 2010-02-04 Fujifilm Corp 放射線変換シートおよび放射線画像検出装置

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1534154A (en) * 1975-04-15 1978-11-29 Agfa Gevaert Radiographic intensifying screens
US4362944A (en) * 1979-02-12 1982-12-07 Kasei Optonix Ltd. Radiographic intensifying screen
JPS5917399B2 (ja) * 1979-07-11 1984-04-20 富士写真フイルム株式会社 放射線像変換パネル
JPS5655939A (en) * 1979-10-15 1981-05-16 Fuji Photo Film Co Ltd Silver halide photographic material
JPS56116777A (en) * 1980-02-20 1981-09-12 Kasei Optonix Co Ltd Phosphor and radiation image transformation panel using the same
JPS5935000B2 (ja) * 1980-07-22 1984-08-25 富士写真フイルム株式会社 放射線像変換用パネル
JPS6457759A (en) * 1987-08-28 1989-03-06 Sharp Kk Field-effect-type semiconductor device

Also Published As

Publication number Publication date
JPS5932900A (ja) 1984-02-22
EP0102010A3 (en) 1984-07-25
EP0102010A2 (fr) 1984-03-07
DE3371009D1 (en) 1987-05-21
JPH0157759B2 (fr) 1989-12-07

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