JPH0731367B2 - Radiation image reading method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a radiation image stored in a radiation image conversion panel.
Regarding the method of reading image information, more specifically, the radiation image
It relates to a reading method that reproduces accurately. BACKGROUND OF THE INVENTION When irradiating a stimulable phosphor with radiation, the radiation energy
When stored energy is excited by visible light etc.
Emit stimulated emission with intensity according to the stored energy
It has been known. Taking advantage of the characteristics of the stimulable phosphor, the radiation image of the human body, etc.
Radiation image conversion panel having stimulable phosphor layer for image information
Accumulated as a latent image in (hereinafter abbreviated as "conversion panel")
Recorded and scanned the conversion panel with stimulated excitation light such as laser light.
To emit stimulated emission and photoelectrically convert the stimulated emission to produce an image signal.
However, a method for visualizing this is described in, for example, US Pat.
Proposed in 9,527 and JP-A-55-12144. Next, read the radiation image information using the conversion panel as described above.
The taking method and device will be described with reference to FIG. The laser light 305 for stimulated excitation light emitted from the laser light source 302 is
It is reflected by the vanometer mirror 304 while being shaken with a constant amplitude.
Conversion panel that stores radiation image information as a latent image
Irradiate with le 301. At this time, the conversion panel 301 moves simultaneously at a right angle to the amplitude direction.
Be made. That is, the conversion panel 301 has an amplitude direction (X
Direction) and sub-scanning in the Y direction.
The entire area of 1 is scanned, and stimulated emission is emitted on that scanning line. On the other hand, close to and parallel to the line of intersection between the amplitude plane and the conversion panel surface.
A light collector 306 having a light-receiving surface 306a is installed at
The condensing body 306 is located next to the light receiving surface 306a which forms an elongated flat cut surface.
It is narrowed to the end and the transmission surface 306b at the terminal end is almost cylindrical.
Photodetector (eg photomultiplier
Etc.) To separate the stimulated emission and the laser light for excitation into 307
They are in contact with each other through the filter 308 of. With the above structure, the stimulated emission generated on the scanning line is the light receiving surface.
Light enters the condenser 306 from 306a and reaches the transmission surface 306b at the end.
Enters the detector 307, receives photoelectric conversion, and is displayed on the image display device 311.
The image transmitted and photoelectrically converted by the image display device 311.
Image information is processed, CRT or magnetic tape or photographic exposure
It is observed as a visible image using materials. It should be noted here that the light receiving surface 306a of the light collector 306 has the light receiving surface 306a.
All light from points within the total reflection angle with respect to the light surface 306a
The light is incident on the condenser 306, and the
Not only stimulated emission excited by laser light 305
Stray light from outside or rays from the surface of the conversion panel 301.
Some of the reflected light or afterglow is completely picked up, and the image
Accurate images mixed with stimulated emission that displays information
It becomes noise light that confuses information. Of the noise light, stray light from outside the device or the conversion panel 30
The reflected light of the laser light from the surface of 1 is shielded, a filter, etc.
Since it can be eliminated by the conversion panel 30
The afterglow from the surface of 1 is a problem. Radiation in the afterglow stimulates the stimulable phosphor of the conversion panel
Afterglow of fluorescence generated by
It is called "light", and the stimulable phosphor accumulates due to radiation.
The excited energy with stimulated excitation light such as laser light
Afterglow of stimulated emission (hereinafter referred to as "stimulated afterglow")
There is. The former fluorescent afterglow is generally related to the index function as shown in FIG.
The numerical decay curve is shown. That is, at time Δt from time t1 to t2
Assuming that radiation is emitted for a period of time and stopped at t2, the emission intensity LO
Does not immediately decay to 0. The decay situation is fluorescent
Depending on the body, the time constant at which the emission intensity is 1 / e is the tan
10 for gustenoate^-6Seconds, rare earth ions and manganese
10 for phosphors containing ions^-3~Ten^-1It can take up to a second
The The fluorescence afterglow is the main afterglow represented by the curve a in FIG.
In addition to the light, the afterglow of subordinate light as shown in FIG.
In many cases In general, the afterglow of the subordinate light emission intensity is
It is weak, but the damping time constant is extremely large. The stimulated emission is irradiated at the time when the stimulated excitation light is present as described above.
To emit from an extremely small area (equivalent to a surface element)
However, the fluorescent afterglow emits light from the entire surface irradiated with radiation,
Point within total reflection angle of light receiving surface 306a of light collector 306 in FIG.
All the light from is collected. In this case, compared to the stimulated emission area of the conversion panel,
Since the converging area of 306 is extremely large,
The afterglow intensity is negligibly small compared to the stimulated emission intensity
Even if it becomes low, the amount of light transmitted to the photodetector
The amount of fluorescence afterglow cannot be ignored. For example, a collection of light collectors 306
Light area is 400mm × 2mm, pixel size is 200μm × 200
Assuming μm, the number of pixels focused on the light collector is 2 × 10^FourIn pieces
Yes, the fluorescence afterglow intensity per pixel is 10 times the stimulated emission intensity.
^-FourThe amount of light transmitted to the photodetector
The ratio of the amount of fluorescent afterglow to the amount of stimulated emission is 2: 1.
U. Thus, in the conventional radiation image information reading method,
After the irradiation, the intensity of the afterglow of the fluorescent light becomes sufficiently negligible.
It is necessary to wait until the reading of the radiation image information
There is a need to read image information in large quantities in rapid succession.
Was difficult. In particular, the main part represented by the curve a in FIG.
If the afterglow time constant is large, or if the main afterglow time constant is
Even if it is small, it has a large time constant represented by curve b in the figure.
It was fatal if there was a strong afterglow. [Object of the Invention] The present invention is a drawback of the conventional radiation image reading method as described above.
In view of the above, the object of the present invention is to provide a fluorescent afterglow.
Accurate image signal matching the actual image
It is possible to obtain high quality reconstructed images with good signal to noise ratio.
The purpose is to provide a radiation image information reading method. Another object of the present invention is to read an image from irradiation of radiation.
Time to improve equipment throughput.
In addition, it is possible to read image information in rapid succession in large quantities.
The purpose is to provide a radiation image information reading method. [Structure of the Invention] In order to achieve the above-mentioned object, the present invention is: i) A radiation transmitted through a subject or emitted from a subject.
The ray is mainly composed of a stimulable phosphor represented by the following general formula
Absorbed in the radiation image conversion panel contained as a general formula M^IX ・ aM^IIX ′_Two・ BM^IIIX ″₃: cA (However, M^IIs at least selected from Li, Na, K, Rb and Cs
A kind of alkali metal, M^IIIs Be, Mg, Ca, Sr, Ba, Zn, C
At least one divalent metal selected from d, Cu and Ni
M^IIIIs Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er,
At least one of three selected from Tm, Yd, Lu, Al, Ga and In
It is a valent metal. X, X'and X "are selected from F, Cl, Br and I
It is at least a kind of halogen. A is Tm, Dy, Pr, H
selected from o, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg
Is at least one metal. Also, a is a numerical value in the range of 0 ≦ a <0.5, and b is 0 ≦ b <
It is a numerical value in the range of 0.5, and c is a numerical value in the range of 0 <c <0.2.
is there. Ii) Immediately after the step i), the radiation image conversion pattern is
The channel is irradiated with stimulated excitation light in the wavelength range of 500 to 900 nm.
By, it is stored and recorded in the radiation image conversion panel.
The technology to emit the radiant energy as stimulated emission
Iii) comprising a step of detecting the stimulated luminescence
It is something. That is, the present inventors have remarkably small amount of fluorescence afterglow and
There is no need to set a waiting time until reading with light.
Uses an alkali halide stimulable phosphor represented by the general formula
The high SN ratio and high quality compared to the conventional method
Image can be given and the throughput of the device can be increased.
This is something that can be improved. The term "immediately" in ii) above means that after irradiation
Within at least 1 minute, preferably within 30 seconds, more preferably
Say within 10 seconds. Hereinafter, the present invention will be described in detail with reference to FIGS. 1 and 2.
Do. FIG. 1 shows the radiation of the present invention having improved characteristics as described above.
FIG. 3 is a schematic diagram showing an example of an apparatus used in the image information reading method.
The The device used in the present invention is not limited to this,
Although the apparatus shown in FIG. 3 may be used, the method of the present invention
Build-in type
A device is more preferable. In this figure, 101 is a radiation source, 102 is a subject, and 103 is the above-mentioned one.
The alkali halide stimulable phosphor layer 104 represented by the general formula
It is a conversion panel that has. Photostimulable fluorescence of conversion panel 103
At the position facing the surface on the body layer 104 side, for example, laser light
Excitation light source 105 that emits excitation light such as
Only the stimulated excitation light 111 emitted from the excitation light source 105 is transmitted.
A filter 110 for making the stimulated excitation light 111 of the conversion panel 103
Light that scans in the width direction, such as a galvanometer mirror
Polarizer 106, stimulable fluorescence excited by the stimulated excitation light
A photodetector 107 for reading the stimulated emission emitted from the body layer 104 and
The photodetector 107 has a common condenser 108 for guiding the stimulated emission.
It is provided on the transfer stage 112 of. The photo detector 1
07 is, for example, a photomultiplier tube and a photomultiplier microchannel.
Photostimulated luminescence that is guided by the condenser 108, such as a flannel plate
Is a filter 10 for separating stimulated excitation light and stimulated emission light.
After being separated at 9, it is photoelectrically detected at the photodetector 107.
The The stimulated excitation light source 105 has a spectrum of 500 to 900 nm.
In addition to a light source that emits light with a distribution, a He-Ne laser and a YAG laser
Laser, Ar laser, semiconductor laser, LED, etc. are used,
Especially, He-Ne laser and semiconductor laser are preferable. 114 is an amplifier of the detected signal, 115 is an amplifier 114
An image reproducing device for reproducing the captured signal as an image, 116
Is an image display device. Further, the surface of the conversion panel 103 on the stimulable phosphor layer 104 side
An erasing light source 113 is provided at a position facing the
It is conveyed along with the stage 112 in the direction of the arrow. This erase
The leaving light source 113 is the excitation wavelength of the phosphor in the stimulable phosphor layer 104.
A light source that emits light including a region, for example, Japanese Patent Application Laid-Open No. 56-113
Halogen lamps such as those shown in No. 92
Lamp, infrared lamp, LED or laser light source is optional
Can be used selectively. In the apparatus of this embodiment having the above structure, the subject 10
2 was placed between the conversion panel 103 and the radiation source 101
After that, when the radiation source 101 is turned on, the conversion panel 104 is stimulated.
Radiation image information of the subject 102 on the fluorescent phosphor layer 104
Is recorded and stored. Immediately after irradiation with this radiation, 500 nm-9
By irradiating stimulated excitation light in the wavelength region of 00 nm,
Radiation energy stored and recorded in the conversion panel 103
Ghee is emitted as stimulated emission. This stimulated emission is an optical inspection
After being collected by the output device 107 and photoelectrically converted, an image reproducing device 115
Is reproduced as an image by the image display device 116.
Is displayed as a visible image. In the irradiation of the stimulated excitation light, the excitation light is run by side.
The inspection is performed by moving the transfer stage 112, and the conversion panel 1
The entire image recording area of 03 is scanned. Also, image reading
After the end, the erasing light source 113 erases the residual image information.
Will return to the initial state. Next, the photostimulability used in the radiation image reading method of the present invention
The phosphor will be explained. It is represented by the following general formula used as the main component in the present invention.
Alkali halide stimulable phosphors are
The fluorescence afterglow is significantly less than that of the phosphor and / or the firefly.
Short afterglow life is required. General formula M^IX ・ aM^IIX ′_Two・ BM^IIIX ″₃: cA (However, M^IIs at least selected from Li, Na, K, Rb and Cs
A kind of alkali metal, M^IIIs Be, Mg, Ca, Sr, Ba, Zn, C
At least one divalent metal selected from d, Cu and Ni
M^IIIIs Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er,
At least one of three selected from Tm, Yd, Lu, Al, Ga and In
It is a valent metal. X, X'and X "are selected from F, Cl, Br and I
It is at least a kind of halogen. A is Tm, Dy, Pr, H
selected from o, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg
Is at least one metal. Also, a is a numerical value in the range of 0 ≦ a <0.5, and b is 0 ≦ b <
It is a numerical value in the range of 0.5, and c is a numerical value in the range of 0 <c <0.2.
is there. ) In particular, among the alkali halide stimulable phosphors, M^IIs K, R
At least one alkali metal selected from b and Cs
, A is at least one metal selected from Tl and Na
Alkali halide stimulable phosphor has low afterglow
And / or fluorescence afterglow has a short life and is excellent. The alkali halide stimulable phosphor must be used alone
Instead, it may be mixed with other stimulable phosphors. Was
However, an alkali halide photostimulable phosphor is used as another photostimulable phosphor.
When used as a mixture with the body, the above-mentioned alkali halide fluorescence
The body mixing ratio should be 50 wt% or more, and further 70 wt% or more
Is preferred. Brightness that may be used by mixing with the alkali halide phosphor
Exhaustible fluorescent materials are described, for example, in JP-A-48-80487.
BaSO_Four: Ax (However, A is one of Dy, Tb, and Tm
It is at least one, and x is 0.001 ≤ x <1 mol%. )
And the MgSO 4 described in JP-A-48-80488_Four: Ax
(However, A is either Ho or Dy, and 0.001 ≦ x
≦ 1 mol%), JP-A-48-804
SrSO listed in No. 89_Four: Ax (where A is Dy, Tb and Tm
At least one of the above, x is 0.001 ≦ x <1 mol%
Is. ), The phosphor represented by JP-A-51-29889
Na listed in₂SO_Four, CaSO_FourAnd BaSO_FourEtc. to Mn, Dy and
Phosphor to which at least one of Tb is added, JP-A-52-3
BeO, LiF, MgSO described in No. 0487_FourAnd CaF₂Firefly
Optical body, Li described in JP-A-53-39277₂B_FourO₇: Cu, A
g and other phosphors, Li described in JP-A-54-47883₂O
・ (B₂O₂) X: Cu (where x is 2 <x ≦ 3), and Li₂O
(B₂O₂) X: Cu, Ag (where x is 2 <x ≦ 3), etc.,
SrS: Ce, Sm, Sr described in U.S. Pat.No. 3,859,527
S: Eu, Sm, La₂O₂S: Eu, Sm and (Zn, Cd) S: Mn, X (where X is
Examples include phosphors represented by halogen. In addition, special
ZnS: Cu, Pb phosphors described in KAISHO 55-12142,
General formula is BaOxAl₂O₃: Eu (however, 0.8 ≦ x ≦ 10)
Barium aluminate phosphor with general formula M^IIO ・ xSiO
₂: A (However, M^IIIs Mg, Ca, Sr, Zn, Cd or Ba, A is Ce, T
b. at least one of Eu, Tm, pb, Tl, Bi and Mn, x
Is 0.5 ≦ x <2.5. ) Alkaline earth gold
Examples include genus silicate phosphors. Also, the general formula is (Ba₁-X-yMgxCay) FX: eEU²⁺ (However, X is at least one of Br and Cl, and x, y and
And e are 0 <x + y ≦ 0.6, xy ≠ 0 and 10 respectively.^-6≤e≤
5 x 10^-2Is a number that satisfies the condition. )
Lucari earth fluorohalide phosphor, JP-A-55-12144
The general formula described in LnOX: xA (where Ln is at least one of La, Y, Gd and Lu, and X is Cl and
And / or Br, A is Ce and / or Tb, and x is 0 <x <0.1
Represents a satisfied number. ), A phosphor represented by
The general formula described in -12145 is (Ba₁−xM^IIx) FX: yA (However, M^IIIs at least one of Mg, Ca, Sr, Zn and Cd.
X, at least one of Cl, Br and I, A is Eu, T
At least one of b, Ce, Tm, Dy, Pr, Ho, Nd, Yb and Er
X and y satisfy the conditions of 0 ≦ x ≦ 0.6 and 0 ≦ y ≦ 0.2.
Represents the number to add. ), A phosphor represented by
The general formula described in No. 89 is BaFX: xCe, yA (where X is C
At least one of l, Br and I, A is In, Tl, Gd, Sm and
And at least one of Zr, where x and y are
0 ≤ x ≤ 2 x 10^-1And 0 <y ≦ 5 × 10^-2Is. )so
Phosphors represented, described in JP-A-55-160078
General formula is M^IIFX ・ xA: yLn (However, M^IIIs at least one of Mg, Ca, Ba, Sr, Zn and Cd.
A, BeO, MgO, CaO, SrO, BaO, ZnO, Al₂O₃, Y₂O₃, La₂O₃, I
n₂O₃, SiO₂, TiO₂.ZrO₂, GeO₂, SnO₂, Nb₂O_Five, Ta₂O_FiveAnd ThO₂
, Ln is Eu, Tb, Ce, Tm, Dy, Pr, Ho, N
at least one of d, Yb, Er, Sm, and Gd, and x is C
at least one of l, Br and I, and x and y are
5 × 10 each^-FiveSatisfies the conditions of ≦ x ≦ 0.5 and 0 <y ≦ 0.2
It is the number to add. ) Divalent metal with activated rare earth element
Fluorohalide phosphor, the general formula is ZnS: A, CdS: A, (Zn, C
d) S: A, ZnS: A, X and CdS: A, X (where A is Cu, Ag, Au, or Mn
And X is halogen. ) Phosphor represented by
General one of the following listed in Kaisho 57-148285
Expression, xM₃(PO_Four)_Two・ NX₂: yA M₃(PO_Four)₂: yA (where M and N are Mg, Ca, Sr, Ba, Zn and Cd, respectively)
At least one of X, at least one of F, Cl, Br and I
A is Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Sb, Tl, Mn and
Represents at least one of Sn. Also, x and y are 0
It is a number that satisfies the condition of <x ≦ 6,0 ≦ y ≦ 1. )
Fluorescent substance, one of the following general formulas nReX₃・ MAX ′₂: xEu nReX₃・ MAX ′₂: xEu, ySm (where Re is at least one of La, Gd, Y, Lu, A is
Potassium earth metal, at least one of Ba, Sr, Ca, X and
X'represents at least one of F, Cl and Br. Also,
x and y are 1 × 10^-Four<X <3 × 10^-1, 1 × 10^-Four<Y <1 × 1
0^-1Is a number that satisfies the following condition, and n / m is 1 × 10^-3<N / m <7
× 10^-1Satisfy the condition ) Phosphors, etc.
It is possible. Photostimulable phosphor used in the radiation image reading method of the present invention
As an example, thallium-activated rubidium bromide stimulable fluorescence
The body (RbBγ: Tl) is as shown in Fig. 2 (a) after X-ray irradiation.
The luminescence characteristics are shown. The curve of FIG. 2 (a) is the radiation image information reading apparatus of FIG.
The excitation light source 10 in FIG.
5 is a 20 mW semiconductor laser, the shape of the light receiving surface 108a of the condensing body 108
Width 400mm, thickness 5mm, replacement panel size is width 350mm, length
It was 420 mm. Also, the X-ray dose applied to the conversion panel is 5
It was 00mR. Furthermore, to obtain the curve in Fig. 2 (a),
Since sub-scanning is not performed, the semiconductor laser light is used.
The main scan was only one line. In Fig. 2 (a), a is fluorescence due to X-ray irradiation, and b
Is the decay curve of the afterglow due to the fluorescence, and c is the stimulated emission intensity.
The Also, the ratio of the stimulated emission intensity and the fluorescence afterglow intensity (SN ratio) is
(S₁-S₂) / S₂Can be obtained with. From the S / N ratio after X-ray irradiation
The time required to obtain stimulated emission was changed variously, and the second
Shown in Figure (b). According to the study by the present inventors, it is preferable that the SN ratio is high.
However, considering the dynamic range of the subject, 1
0³Greater than 10^Four~Ten^FivePreferred to be degree
Yes. However, the SN ratio is 5 × 10^FiveThe above is excess quality
is there. Therefore, as is clear from FIGS. 2 (a) and 2 (b).
With thallium used in the radiation image reading method of the present invention
Rubidium bromide stimulable phosphor (RbBγ: Tl) is fluorescent afterglow
Is less and has a shorter life, so about 2 seconds after X-ray irradiation
It is possible to scan images with a sufficiently high SN ratio. Also got
Both the quality of the radiographic image and the read throughput
Start reading within 1 minute at the longest after X-ray irradiation
Is preferable, and there is almost no deterioration in image quality even within 30 seconds.
None, more preferable. However, 1 minute or more after X-ray irradiation
That reduces read throughput and is economical
It will be a disadvantage. On the other hand, FIG. 5 (a) shows a conventionally known divalent europium
Active barium fluorobromide stimulable phosphor (BaFBr: Eu²⁺) Emission
Shows the characteristics, a is the fluorescence by X-ray irradiation, b is the fluorescence
The decay curve of the afterglow due to, c is the stimulated emission. Fig. 5
(B) shows He as a stimulated excitation light source instead of a semiconductor laser.
-The same as in Fig. 2 (b) except that a Ne laser was used.
Is the SNR obtained by Conventional divalent europium activated barium fluorobromide stimulable firefly
Since the optical body has a lot of fluorescent afterglow and has a long life, the SN ratio is 10³
To achieve the above, at least 1 minute after X-ray irradiation
After that, it is necessary to perform image reading, and the reading throughput
Is significantly reduced. The stimulable phosphor layer is supported by, for example, the following method.
It can be formed on the body. First, the stimulable phosphor particles and the binder are mixed with a suitable solvent.
In addition to this, it is thoroughly mixed and stimulable fluorescent in the binder solution.
Prepare a coating solution in which body particles are uniformly dispersed. Examples of the binder for the stimulable phosphor layer include gelatin and the like.
Bolisaccharides such as protein and dextran or
Natural polymeric substances such as labia gum; and polyvinyl
Chiral, polyvinyl acetate, nitrocellulose, ethyl
Cellulose, vinylidene chloride / vinyl chloride copolymer,
Polymethylmethacrylate, vinyl chloride / vinyl acetate
Polymer, polyurethane, cellulose acetate butyre
Sheets, polyvinyl alcohol, linear polyester, etc.
Binders represented by such synthetic polymer substances are listed.
You can get it. Examples of the solvent for adjusting the coating solution include methanol and ethanol.
Alcohol, n-propanol, n-butanol, etc.
: Methylene chloride, ethylene chloride, etc.
Hydrocarbons containing chlorine atoms; acetone, methyl ethyl keto
And ketones such as methyl isobutyl ketone: Methyl acetate
Lower fatty acid vinegar and lower alcohol such as
Esters with rucor; dioxane, ethylene glycol
Ruethyl ether, ethylene glycol monomethyl ester
Ethers such as ter: and list their mixtures
be able to. The mixing ratio of the binder and the stimulable phosphor particles in the coating liquid is
Target conversion panel characteristics, types of stimulable phosphor particles
Generally, a binder and a photostimulable phosphor
Mixing ratio with particles is from 1: 1 to 1: 100 (weight ratio)
Selected, and especially in the range 1: 8 to 1:40 (weight ratio)
It is preferable to choose from It should be noted that the coating liquid is a stimulable phosphor in the coating liquid.
Dispersant for improving the dispersibility of particles, and also after formation
Binder and stimulable phosphor particles in the stimulable phosphor layer
Various plasticizers to improve the bond strength between
Additives may be mixed. Used for such purposes
Examples of dispersants that can be used include phthalic acid, stearic acid,
Caproic acid, lipophilic surfactant, etc. can be mentioned.
The Examples of plasticizers include triphenyl phosphate and phosphorus.
Phosphates such as tricresyl acid and diphenyl phosphate;
For example, diethyl phthalate or dimethoxyethyl phthalate
Talic acid ester; Ethyl glycolate Phthalylethyl ester,
Glycolic acid such as butyl phthalyl butyl glycolate
Esters: And triethylene glycol and adipine
Polyester with acid, diethylene glycol and succinic acid
Polyethylene glycol such as polyester and fat
Examples include polyesters with group dibasic acids
The Photostimulable phosphor particles and binder prepared as described above
Then, the coating solution containing and is uniformly applied to the surface of the support.
By doing so, a coating film of the coating liquid is formed. Of this coating liquid
The coating operation is carried out by a conventional coating means such as a doctor blade,
By using a roll coater, knife coater, etc.
Can be done. After forming the coating film, dry it by gradually heating the coating film.
The formation of the stimulable phosphor layer on the support is completed. Kagayaki
The thickness of the exhaustive phosphor layer depends on the characteristics of the target conversion panel and the brightness.
Of the type of stimulable phosphor particles, the binder and the stimulable phosphor particles
Normally 20 μm to 1 mm, depending on the mixing ratio
And However, it is preferable that this layer thickness is 50 to 500 μm.
Good. Further, the stimulable phosphor layer is not always on the support as described above.
It is not necessary to directly apply the coating solution to the
Apply the coating solution on a sheet such as a protective layer and dry it.
After forming the phosphor layer with, press it onto the support.
Or stimulable with the support by using an adhesive
It may be joined to the phosphor layer. The stimulable phosphor layer may be composed of a single layer,
Two or more layers may be laminated. Another method of forming the photostimulable phosphor layer is vapor deposition.
The As the vapor deposition method, vacuum vapor deposition method, sputtering
Method, CVD method, etc. can be used. Alkali halide Kagayaki
The photostimulable phosphor is formed by the vapor deposition method to form the photostimulable phosphor.
It is easy to use this method. In the conversion panel according to the present invention, the stimulable phosphor layer has a self
When it has no supporting ability, it supports the stimulable phosphor layer.
Support is provided. As the support, various types
Child material, glass, metal, etc. are used.
Film, polyester film, polyethylene film
Rephthalate film, Polyamide film, Polyimide
Film, triacetate film, polycarbonate
Film such as plastic film, aluminum film
Sheet, metal sheet such as iron sheet, copper sheet or the like
A metal sheet having an oxide coating layer is preferred. The surface of these supports may be smooth or stimulable.
As a matte surface for the purpose of improving the adhesiveness with the phosphor layer
Good. Also, the surface of the support may be an uneven surface,
It may be a structure in which tiled boards that are isolated are spread. former
In the case of, the photostimulable phosphor layer is subdivided by the uneven surface.
Therefore, the sharpness of the image is further improved. In the latter case
The photostimulable phosphor layer maintains the contours of the support tile plate.
However, as a result, the stimulable phosphor layer cracks.
The columnar block of photostimulable phosphor isolated by
Therefore, the sharpness of the image is further improved. In addition, these supports have an improved adhesiveness with the stimulable phosphor layer.
Undercoat layer on the surface where the stimulable phosphor layer is provided for the purpose of raising
May be provided. Also, the layer thickness of these supports is
It depends on the material of the support, etc.
00 μm, and more preferably 80 to 80 from the viewpoint of handling.
It is 1000 μm. In the conversion panel according to the present invention, the photostimulability is generally
On the surface opposite to the surface on which the phosphor layer is provided, stimulable fluorescent
A protective layer is provided to physically or chemically protect the body layer.
You may be kicked. This protective layer stimulates the coating liquid for protective layer
It may be applied directly on the phosphor layer, or it may be formed separately in advance.
A protective layer may be adhered on the stimulable phosphor layer. Or another
The procedure for forming a stimulable phosphor layer on the protective layer that has been formed
Very good. As a material for the protective layer, cellulose acetate,
Nitrocellulose, polymethylmethacrylate, polybi
Nylbutyral, polyvinyl formal, polycarbonate
Sheet, polyester, polyethylene terephthalate, polyethylene
Polyethylene, polyvinylidene chloride, nylon, polytetrafluoroethylene
Ethylene fluoride, polytrifluoride-ethylene chloride, tetrafluoride
Ethylene-hexafluoropropylene copolymer, vinylidene chloride
-Vinyl chloride copolymer, vinylidene chloride-acryloni
Ordinary protective layer materials such as toll copolymers are used. Well
In addition, this protective layer is made of Si by vapor deposition, sputtering, etc.
C, SiO₂, SiN, Al₂O₃Even if it is formed by laminating inorganic substances such as
Good. The thickness of these protective layers is generally 0.1 μm to 100 μm.
About m is preferable. [Examples] Hereinafter, the present invention will be described using examples. Example 1 The conversion panel is RbBr: Tl⁺13 parts by weight of stimulable phosphor
And 1 part by weight of polyvinyl butyral as a solvent (cyclohexene
Sanon) to disperse and
Apply evenly on the tarate substrate, let stand overnight and let it dry naturally.
A stimulable phosphor layer of about 300 μm is formed by drying.
I made it. 50 X-rays with a tube voltage of 80KV are applied to this conversion panel.
After irradiating 0 milli-roentgen and 10 seconds later, with a 25mW semiconductor laser.
The image signal was read. Fluorescent afterglow just before reading the image signal
The ratio of the signal size to the image signal size (SN ratio)
The results are shown in Table 1. Comparative example RbBr: Tl as stimulable phosphor⁺Instead of BaFBr: Eu²⁺For
A conversion panel was prepared in the same manner as in Example 1 except that
The image signal was read with a He-Ne laser 10 seconds after irradiation. Picture
The magnitude of the fluorescence afterglow signal and the image just before reading the image signal
Table 1 shows the ratio (SN ratio) to the signal magnitude. Example 2 As in Example 1, RbBr: Tl⁺Photostimulable phosphor 60% by weight, BaFB
r: Eu²⁺A conversion panel was prepared using 40% by weight. next,
The conversion panel was irradiated with X-rays for 10 seconds as in Example 1.
Later, we read the image signal with a semiconductor laser. Read image signal
Magnitude of fluorescence afterglow signal and magnitude of the image signal just before taking
The ratio (SN ratio) to and is shown in Table 1.From Example 1 and Comparative Example, alkali was used as the stimulable phosphor.
RbBr: Tl, a halide photostimulable phosphor⁺When using a phosphor
In this case, even if the image is read immediately after X-ray irradiation, an image with a high SN ratio is obtained.
It was obtained. In addition, the alkali halide phosphor is added from Example 2.
The afterglow of the fluorescent light decreases, and the image is read immediately after X-ray irradiation.
Sufficiently high SN ratio was obtained even if it went. As described above, the radiation image information reading method of the present invention
The methods are: i) Emissions transmitted through the subject or emitted from the subject.
The ray is mainly composed of a stimulable phosphor represented by the following general formula
Absorbed in the radiation image conversion panel contained as a general formula M^IX ・ aM^IIX ′_Two・ BM^IIIX ″₃: cA (However, M^IIs at least selected from Li, Na, K, Rb and Cs
A kind of alkali metal, M^IIIs Be, Mg, Ca, Sr, Ba, Zn, C
At least one divalent metal selected from d, Cu and Ni
M^IIIIs Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er,
At least one of three selected from Tm, Yd, Lu, Al, Ga and In
It is a valent metal. X, X'and X "are selected from F, Cl, Br and I
It is at least a kind of halogen. A is Tm, Dy, Pr, H
o, Nd, Yb, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg
At least it is a kind of metal. Also, a is a numerical value in the range of 0 ≦ a <0.5, and b is 0 ≦ b <
It is a numerical value in the range of 0.5, and c is a numerical value in the range of 0 <c <0.2.
is there. Ii) Immediately after the step i), the radiation image conversion pattern is
The channel is irradiated with stimulated excitation light in the wavelength range of 500 to 900 nm.
By, it is stored and recorded in the radiation image conversion panel.
The technology to emit the radiant energy as stimulated emission
Iii) The step of detecting the stimulated luminescence;
There is little noise, and an accurate image signal that matches the actual image is obtained and SN
It is possible to obtain a high quality reconstructed image with good ratio. Further, according to the present invention, the amount of fluorescent afterglow is extremely small, and
Before there is no need to set a waiting time until reading with afterglow
The alkali halide stimulable phosphor represented by the general formula
Since it is used, from the irradiation of radiation to the reading of images
It can shorten the time and improve the throughput of the device.
It is not possible to read image information in rapid succession in large quantities.
Which has various excellent effects.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an apparatus for carrying out the method of the present invention, and FIG. 2 is an example of a stimulable phosphor used in the radiation image reading method of the present invention, which is thallium-activated rubidium bromide. FIG. 3 is a diagram showing the emission characteristics of a stimulable phosphor, FIG. 3 is a schematic perspective view of an apparatus for carrying out a conventional radiation image information reading method, and FIG. 4 is a diagram showing a decay curve of fluorescence afterglow. The figure shows the emission characteristics of a conventionally known divalent europium-activated barium fluorobromide stimulable phosphor. 101 …… Radiation source 102 …… Subject 103 …… Conversion panel 104 …… Alkali halide stimulable phosphor layer 105 …… Stimulated excitation light source 108 …… Concentrator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Amitani No. 1 Sakura-cho, Hino-shi, Tokyo Photo Konishi Roku Photo Industry Co., Ltd. (72) Inventor Fumio Shimada No. 1 Sakura-cho, Hino-shi, Tokyo Photo Photo Roku Konishi In the company

Claims (2)

[Claims] 1. A step of: i) a radiation image conversion panel containing a stimulable phosphor represented by the following general formula as a main component, which absorbs radiation transmitted through a subject or emitted from a subject; ^{M I X · aM II X '} 2 · bM III X "3: cA ( where, M ^I is at least one alkali metal selected Li, Na, K, from Rb and Cs, M ^II is be, Mg, Ca, Sr, Ba, Zn, C
d, Cu and at least one divalent metal selected from Ni. M ^III is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er,
It is at least one trivalent metal selected from Tm, Yd, Lu, Al, Ga and In. X, X ′ and X ″ are at least one halogen selected from F, Cl, Br and I. A is Tm, Dy, Pr, H
It is at least one metal selected from o, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg. Also, a is 0 ≦ a <0.5
Is a numerical value in the range of, b is a numerical value in the range of 0 ≦ b <0.5, and c is a numerical value in the range of 0 <c <0.2. Ii) Immediately after completion of the step i), the radiation image conversion panel is irradiated with stimulated excitation light in the wavelength region of 500 to 900 nm so that the radiation energy stored and recorded in the radiation image conversion panel is irradiated. A radiation image reading method comprising: a step of releasing as stimulated emission; iii) a step of detecting the stimulated emission. 2. The radiation image reading method according to claim 1, wherein the stimulated excitation light is a semiconductor laser light.