Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2001-01-29
2003-06-03
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S917000, C252S400610, C250S484400, C427S157000, C427S212000, C427S370000
Reexamination Certificate
active
06572986
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a radiation image storage panel for use in a radiation image recording and reproducing techniques, in which phosphors are utilized. This invention also relates to a process for producing the radiation image storage panel.
2. Description of the Related Art
As techniques for obtaining radiation images for medical diagnosis and radiation images of various objects in a non-destructive mode and utilizing the radiation images for making medical diagnosis, flaw detecting inspections, and a like, radiography utilizing a combination of a silver halide photographic material (hereinbelow referred to simply as the photographic material) and an intensifying screen has heretofore been used in practice. With the radiography, radiation carrying image information of an object is irradiated to the intensifying screen, and a phosphor contained in the intensifying screen is excited by the radiation to emit near ultraviolet light or visible light. The emitted light impinges upon the photographic material, and a radiation image of the object is recorded on the photographic material The radiation image is utilized for making medical diagnosis, flaw detecting inspections, or the like. Specifically, the photographic material comprises a substrate and a silver halide emulsion layer, which is overlaid on one surface of the substrate, or silver halide emulsion layers, which are overlaid on opposite surfaces of the substrate. Also, an intensifying screen is brought into close contact with one surface of the photographic material, or intensifying screens are brought into close contact with opposite surfaces of the photographic material. The combination of the photographic material and at least one intensifying screen is exposed to radiation carrying image information of the object, and the radiation image is thereby formed.
In lieu of the conventional radiography described above, radiation image recording and reproducing techniques utilizing stimulable phosphors have heretofore been used in practice. The stimulable phosphors have the properties such that, when the stimulable phosphors having absorbed energy from radiation are exposed to an electromagnetic wave, such as visible light or infrared rays, the stimulable phosphors are stimulated to emit the energy as fluorescence. The radiation image recording and reproducing techniques are described in, for example, U.S. Pat. No. 4,239,968. The radiation image recording and reproducing techniques utilize a radiation image storage panel (referred to also as the stimulable phosphor sheet) provided with a stimulable phosphor. With the radiation image recording and reproducing techniques, the stimulable phosphor of the radiation image storage panel is caused to absorb radiation, which carries image information of an object or which has been radiated out from a sample, and thereafter the stimulable phosphor is exposed to an electromagnetic wave (stimulating rays), such as visible light or infrared rays, which causes the stimulable phosphor to produce the fluorescence (i.e., to emit light) in proportion to the amount of energy stored thereon during its exposure to the radiation. The produced fluorescence (the emitted light) is photoelectrically detected to obtain an electric signal. The electric signal is then processed, and the processed electric signal is utilized for reproducing a visible image of the object or the sample.
The radiation image recording and reproducing techniques have the advantages in that a radiation image containing a large amount of information can be obtained with a markedly lower dose of radiation than in the conventional radiography utilizing the radiation film and the intensifying screen. Therefore, the radiation image recording and reproducing techniques are efficient particularly for direct medical radiography, such as the X-ray image recording for medical diagnosis.
Basically, the radiation image storage panel utilized for the radiation image recording and reproducing techniques comprises a substrate and a stimulable phosphor layer overlaid on one surface of the substrate. In cases where the stimulable phosphor layer has self-supporting properties, the radiation image storage panel need not necessarily be provided with the substrate. Ordinarily, a transparent protective film is formed on the surface of the stimulable phosphor layer, which surface is opposite to the surface that stands facing the substrate. The transparent protective layer protects the stimulable phosphor layer from chemical deterioration or physical shocks.
The stimulable phosphor layer comprises a binder and stimulable phosphor particles dispersed in the binder. The stimulable phosphor has the properties such that, when the stimulable phosphor is caused to absorb radiation, such as X-rays, and is then exposed to the stimulating rays, the stimulable phosphor emits light in proportion to the amount of energy stored thereon during its exposure to the radiation. Therefore, when the radiation image storage panel is exposed to the radiation, which carries image information of an object or which has been radiated out from a sample, the stimulable phosphor layer of the radiation image storage panel absorbs the radiation in proportion to the dose of radiation, and a radiation image of the object or the sample is stored as an image of energy from the radiation on the radiation image storage panel. The radiation image storage panel is then exposed to the stimulating rays, and the image having been stored on the radiation image storage panel can be detected as the light emitted by the radiation image storage panel. The emitted light is detected photoelectrically to obtain an image signal, the image signal is processed, and the thus obtained processed image signal can then be utilized for reproducing the radiation image of the object or the sample as a visible image.
As described above, the radiation image recording and reproducing techniques are the advantageous image forming techniques. However, as in the cases of an intensifying screen employed in the conventional radiography, it is desired that the radiation image storage panel utilized for the radiation image recording and reproducing techniques has a high sensitivity and can yield an image of good image quality (with respect to sharpness, graininess, and the like).
Basically, the sensitivity of the radiation image storage panel depends upon a total light emission intensity of the stimulable phosphor, which is contained in the radiation image storage panel. The total light emission intensity depends upon light emission luminance of the stimulable phosphor itself and the content of the stimulable phosphor in the stimulable phosphor layer. In cases where the content of the stimulable phosphor in the stimulable phosphor layer is high, a high absorptivity is capable of being obtained with respect to the radiation, such as the X-rays. Therefore, in cases where the content of the stimulable phosphor in the stimulable phosphor layer is high, a high sensitivity is capable of being obtained, and the image quality (in particular, with respect to the graininess) is capable of being enhanced. In cases where the content of the stimulable phosphor in the stimulable phosphor layer is kept at a predetermined value, if the stimulable phosphor particles are packed closely in the stimulable phosphor layer, the thickness of the stimulable phosphor layer can be set to be thin. Therefore, in such cases, spreading of the stimulating rays due to scattering in the stimulable phosphor layer is capable of being minimized, and an image having a high sharpness is capable of being obtained.
As radiation image storage panels provided with a stimulable phosphor layer, in which a stimulable phosphor is packed closely, and processes for producing the radiation image storage panels, the applicant proposed radiation image storage panels, in which a void content in the stimulable phosphor layer has been reduced by performing compression processing on the stimulable phosphor layer, and
Fukui Shinichiro
Hirano Shigeo
Inoue Noriyuki
Iwabuchi Yasuo
Ogawa Hiroshi
Fuji Photo Film Co. , Ltd.
Garrett Dawn
Kelly Cynthia H.
LandOfFree
Radiation image storage panel and process for producing the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Radiation image storage panel and process for producing the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radiation image storage panel and process for producing the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3092836