JPH11160818A - Radiograph erasing method and device and radiograph reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely erase an afterimage remaining on a stimulable phosphor plate without depending on the temperature of an erasing part. SOLUTION: This reader is provided with an image reading part 5 reading a radiograph accumulated and recorded on the stimulable phosphor plate 12 by radiating simulating light to the plate 12 on which the radiograph is accumulated and recorded and detecting stimulated luminescence, and the erasing part radiating erasing light from an erasing light source to the plate 12 from which the radiograph is read by the reading part 5. In such a case, the temperature dependency of the intensity of emitted light of the erasing light source is set to reverse characteristic to the temperature dependency of the erasing characteristic of the plate 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image erasing method for irradiating an erasing light from an erasing light source to a stimulable phosphor plate from which a radiation image has been read, and erasing the stimulable phosphor plate from which a radiation image has been read. A radiation image erasing device having an erasing unit for irradiating erasing light from a light source, and irradiating the stimulable phosphor plate on which the radiation image is accumulated and recorded with excitation light to detect stimulated emission, and An image reading unit that reads the radiation image stored and recorded on the body plate, and an erasing unit that irradiates erasing light from an erasing light source to the stimulable phosphor plate from which the radiation image has been read by the image reading unit. The invention relates to a radiation image reading apparatus having the same.

[0002]

2. Description of the Related Art X-rays are taken on a stimulable phosphor plate, and the stimulable phosphor plate on which a radiation image is accumulated and recorded is irradiated with excitation light to detect stimulated emission and accumulate on the stimulable phosphor plate. In recent years, a radiation image reading apparatus that reads a recorded radiation image has been put to practical use.

However, since the residual image remains on the stimulable phosphor plate only by irradiation with the excitation light, the radiation image is read by the image reading means in order to reuse the stimulable phosphor plate. An erasing unit that irradiates the stimulable phosphor plate with erasing light from an erasing light source,
A radiation image erasing device provided in a radiation image reading device or having an erasing unit for irradiating erasing light from an erasing light source to the stimulable phosphor plate from which a radiation image has been read has been put to practical use or proposed. .

[0004]

However, this was not a problem while the radiation image reading device and the radiation image erasing device were installed under certain conditions, but they have been installed in various places. In addition, there has been a problem that the afterimage remaining on the stimulable phosphor plate is not sufficiently erased.

As a result of diligent studies on this problem, the erasing characteristics of the stimulable phosphor plate have a temperature dependence, and depending on the temperature of the erasing section of the radiation image reading device or the erasing device of the radiation image, the stimulable phosphor plate may have a high temperature. It has been found that a case where the residual afterimage is not sufficiently erased occurs.

Accordingly, the present invention has been made after studying various solutions for solving these problems.
It is an object of the present invention to sufficiently erase an afterimage remaining on a stimulable phosphor plate regardless of the temperature of an erasing section.

[0007]

The above object of the present invention can be attained by all the matters for specifying the invention described in the claims. Hereinafter, each claim will be described. However, items that are the same as those described in the cited items may be omitted.

[0010] (1) In a radiation image erasing method for irradiating an erasing light from an erasing light source to a stimulable phosphor plate from which a radiation image has been read, the temperature dependence of the luminous intensity of the erasing light source is such that A radiation image erasing method characterized in that the erasing characteristics of the luminescent phosphor plate are opposite to the temperature dependence. [Claim 2] "The stimulable phosphor plate has a characteristic that the higher the temperature, the easier it is to erase.
The maximum temperature of the erasable stimulable phosphor plate set in the device that irradiates the stimulable phosphor plate with erasing light from the erasing light source is Tx, the minimum temperature is Tn,
When the maximum temperature of the environmental temperature set by the erasing light source that irradiates the stimulable phosphor plate with the erasing light is TX, and the minimum temperature is TN, the emission intensity E (TX of the erasing light source when the environmental temperature is TX) ) Is a value lower than the emission intensity E (TN) of the erasing light source when the environmental temperature is TN, and the erasing characteristic R (Tx) of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tx. Is the erasing characteristic R (Tn) of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tn.
2. The radiation image erasing method according to claim 1, wherein the value becomes larger. According to the first and second aspects of the present invention, it is possible to sufficiently erase the residual image remaining on the stimulable phosphor plate regardless of the temperature of the erasing section.

[Claim 3] "The stimulable phosphor plate is a plate provided with a stimulable phosphor layer represented by the following chemical formula [23].
3. The radiation image erasing method according to 1.

[23] Rb (Br _x , I _1-x ): yTl (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁶ ≦ y ≦ 1 × 10 ⁻² . [Claim 4] "The stimulable phosphor plate is a plate provided with a layer of a stimulable phosphor represented by the following chemical formula [24]. Radiation image erasing method.

[24] BaF (Br _x , I _1-x ): yEu (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁴ ≦ y ≦ 1 × 10 ⁻² . According to the invention as set forth in claims 3 and 4, the afterimages remaining on the stimulable phosphor plate are sufficiently erased irrespective of the temperature of the erasing section, while having good characteristics as the stimulable phosphor plate. You can do so.

[5] The radiation image erasing method according to any one of [2] to [4], wherein the erasing light source is a light emitting diode. According to the invention as set forth in claim 5, since the luminous efficiency is high, the afterimage remaining on the stimulable phosphor plate is sufficiently erased irrespective of the temperature of the erasing section while reducing the power consumption for erasing. You can do so.

[Claim 6] In a radiographic image erasing apparatus having an erasing section for irradiating an erasing light from an erasing light source to a stimulable phosphor plate from which a radiographic image has been read, the temperature dependence of the emission intensity of the erasing light source The radiation image erasing device is characterized in that the characteristics are opposite to the temperature dependence of the erasing characteristics of the stimulable phosphor plate. [Claim 7] "The stimulable phosphor plate has a characteristic that the higher the temperature, the more easily the erasure is performed, and the erasable light set by an apparatus that irradiates the stimulable phosphor plate with erasing light from an erasing light source. The maximum temperature of the stimulable phosphor plate is Tx
Where Tn is the minimum temperature, TX is the maximum environmental temperature set by the erasing light source that irradiates the stimulable phosphor plate with erasing light, and TX is the environmental temperature when the minimum temperature is TN. Intensity E (TX) of the erasing light source at
Is a value smaller than the emission intensity E (TN) of the erasing light source when the environmental temperature is TN, and the erasing characteristic R of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tx.
7. The radiation image erasing apparatus according to claim 6, wherein (Tx) is such that the temperature of the stimulable phosphor plate is larger than the erasing characteristic R (Tn) of the stimulable phosphor plate at Tn. . According to the inventions set forth in claims 6 and 7, the residual image remaining on the stimulable phosphor plate can be sufficiently erased regardless of the temperature of the eraser.

[Claim 8] "The stimulable phosphor plate is a plate provided with a stimulable phosphor layer represented by the following chemical formula [23].
A radiation image erasing apparatus according to claim 1.

[23] Rb (Br _x , I _1-x ): yTl (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁶ ≦ y ≦ 1 × 10 ⁻² . [Claim 9] "The stimulable phosphor plate is a plate provided with a stimulable phosphor layer represented by the following chemical formula [24]. Radiation image erasing device.

[24] BaF (Br _x , I _1-x ): yEu (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁴ ≦ y ≦ 1 × 10 ⁻² . According to the invention as set forth in claims 8 and 9, the afterimages remaining on the stimulable phosphor plate are sufficiently erased irrespective of the temperature of the erasing section while having good characteristics as the stimulable phosphor plate. You can do so.

[10] The radiation image erasing apparatus according to any one of [7] to [9], wherein the erasing light source is a light emitting diode. According to the invention described in claim 10, the luminous efficiency is high,
The residual image remaining on the stimulable phosphor plate can be sufficiently erased irrespective of the temperature of the erased portion while reducing the power consumption for erasing.

[Claim 11] [The radiation image stored and recorded on the stimulable phosphor plate by irradiating the stimulable phosphor plate with the radiation image accumulated and recorded with excitation light to detect stimulated emission, A radiation image reading apparatus comprising: an image reading unit that reads the radiation image; and an erasing unit that irradiates an erasing light from an erasing light source to the stimulable phosphor plate from which the radiation image has been read by the image reading unit. A radiation image reading device, wherein the temperature dependence of the emission intensity is opposite to the temperature dependence of the erasing characteristics of the stimulable phosphor plate. [Claim 12] "The stimulable phosphor plate has a characteristic that the higher the temperature, the more easily the erasure is performed, and the erasable light set by an apparatus for irradiating the stimulable phosphor plate with erasing light from an erasing light source. The maximum temperature of the stimulable phosphor plate
x, the minimum temperature is Tn, and the maximum temperature of the environmental temperature set by the erasing light source for irradiating the stimulable phosphor plate with the erasing light is TX, and when the minimum temperature is TN, the environmental temperature is Emission intensity E (TX) of the erasing light source at TX
Is a value smaller than the emission intensity E (TN) of the erasing light source when the environmental temperature is TN, and the erasing characteristic R of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tx.
The radiation image reading apparatus according to claim 11, wherein (Tx) is such that the temperature of the stimulable phosphor plate becomes a value larger than the erasing characteristic R (Tn) of the stimulable phosphor plate at Tn. . According to the eleventh and twelfth aspects of the present invention, the residual image remaining on the stimulable phosphor plate can be sufficiently erased regardless of the temperature of the eraser.

[Claim 13] "The stimulable phosphor plate is a plate provided with a stimulable phosphor layer represented by the following chemical formula [23]. A radiation image reading apparatus according to claim 1.

[23] Rb (Br _x , I _1-x ): yTl (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁶ ≦ y ≦ 1 × 10 ⁻² . [Claim 14] "The stimulable phosphor plate is a plate provided with a layer of a stimulable phosphor represented by the following chemical formula [24]. Radiation image reading device.

[24] BaF (Br _x , I _1-x ): yEu (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁴ ≦ y ≦ 1 × 10 ⁻² . According to the invention as set forth in claims 13 and 14, the afterimages remaining on the stimulable phosphor plate are sufficiently erased irrespective of the temperature of the erasing section while having good characteristics as the stimulable phosphor plate. You can do so.

[15] The radiation image reading apparatus according to any one of [12] to [14], wherein the erasing light source is a light emitting diode. According to the invention of claim 15, since the luminous efficiency is high,
The residual image remaining on the stimulable phosphor plate can be sufficiently erased irrespective of the temperature of the erased portion while reducing the power consumption for erasing.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an image reading section
The stimulable phosphor plate on which the radiation image is accumulated and recorded is irradiated with excitation light to detect stimulated emission and read the radiation image accumulated and recorded on the stimulable phosphor plate.

In the present invention, the erasing section irradiates the stimulable phosphor plate with erasing light from an erasing light source. In a radiation image reading apparatus, the radiation image is read by the image reading means. And irradiating the stimulable phosphor plate with erasing light from an erasing light source.

The erasing light source may be any one that emits erasing light for erasing the residual image remaining on the stimulable phosphor plate. For example, a point light source, a line light source, or a surface light source Or other forms of light source.

Then, as shown in the embodiment,
While relatively moving the light source and the stimulable phosphor plate with a small area with respect to the recording surface of the stimulable phosphor plate, the afterimage remaining on the stimulable phosphor plate may be erased, A light source is arranged so that erasing light can be irradiated simultaneously to the entire recording surface of the stimulable phosphor plate,
Afterimages remaining on the stimulable phosphor plate may be erased, or may be erased in other forms.

When erasing the residual image on the stimulable phosphor plate while moving the light source having a small area and the stimulable phosphor plate relative to the recording surface of the stimulable phosphor plate, As shown in the embodiment, either the configuration in which the stimulable phosphor plate is moved and the configuration in which the stimulable phosphor plate is fixed and the light source is moved are used. You may.

Further, if a light source is arranged so that the erasing light can be simultaneously applied to the entire recording surface of the stimulable phosphor plate and the residual image remaining on the stimulable phosphor plate is erased, the erasing time is reduced. Can be shortened, which is preferable.
In this case, it is preferable to arrange the light emitting diodes two-dimensionally because power consumption is small and the size is reduced.

As a method of lighting the erasing light source, a method of continuously lighting may be used, but a method of intermittently lighting the pulse is preferable because the erasing characteristics are improved.
In particular, the stimulable phosphor plate has the following chemical formula [2]
In the case of a plate provided with a layer of a stimulable phosphor represented by 3) or a plate provided with a layer of a stimulable phosphor represented by a chemical formula [24] described below, The intermittent pulse lighting is preferable because the erasing characteristics are significantly improved.

The frequency of the pulse drive for intermittent pulse lighting is preferably 10 Hz or more (especially 100 Hz or more), and 100 kHz or less (especially 10 kHz or less) from the viewpoint of improving erasing characteristics. It is preferred that Further, the duty ratio in this case is preferably 50% or more, and more preferably 90% or less, from the viewpoint of improving the erasing characteristics. In this case, a light-emitting diode is preferably used as the erasing light source because a light-emitting response speed to a supply current is high.

Erasing characteristic R (T) of stimulable phosphor plate
Is defined by the following equation. Note that the temperature of the stimulable phosphor plate is T, the radiation accumulated energy level when a radiation image is read is E1 (T), and the radiation accumulated energy level immediately after erasure is E2 (T).

R (T) = E1 (T) / E2 (T) The larger the value of the erasing characteristic R (T) of the stimulable phosphor plate, the easier the erasing is.

The radiation stored energy level E1 (T) when the radiation image was read was determined by reading the radiation image stored and recorded on the stimulable phosphor plate irradiated with a predetermined amount of X-rays. This is a value obtained by converting the read signal value at the time into an X-ray dose. The radiation accumulated energy level E2 (T) immediately after the erasing is used to erase the radiation image on the stimulable phosphor plate from which the image has been read in order to obtain the radiation accumulated energy level E1 (T) when the radiation image has been read. Immediately after irradiating the erasing light from the light source, this is a value obtained by converting a read signal value obtained when an image of a radiation image stored and recorded on the stimulable phosphor plate is read into an X-ray dose.

In the present invention, the temperature dependence of the erasing characteristic R (T) of the stimulable phosphor plate is determined by an erasable device set by irradiating the stimulable phosphor plate with erasing light from an erasing light source. When the maximum temperature of the stimulable phosphor plate is Tx and the minimum temperature is Tn, the erasing characteristic R (Tx) and the stimulable phosphor of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tx This means which of the erasing characteristics R (Tn) of the stimulable phosphor plate at the plate temperature Tn is larger.

In the present invention, the temperature dependence of the luminous intensity E (T) of the erasing light source is determined by setting the maximum temperature of the ambient temperature set by the erasing light source for irradiating the stimulable phosphor plate with the erasing light as TX. , When the minimum temperature is TN, which of the emission intensity E (TX) of the erasing light source when the environmental temperature is TX and the emission intensity E (TN) of the erasing light source when the environmental temperature is TN is larger. .

"The temperature dependency of the emission intensity of the erasing light source is the opposite of the temperature dependency of the erasing characteristics of the stimulable phosphor plate" means "the erasing light source at an environmental temperature of TX." The emission intensity E (TX) of the storage phosphor plate is higher than the emission intensity E (TN) of the erasing light source when the environmental temperature is TN. Erase characteristics R (Tx) Erase characteristics R (Tn) of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tn. Erase characteristics R (T) of the stimulable phosphor plate.
Or "the ambient temperature is TX
The emission intensity E (TX) of the erasing light source at the time of environmental temperature becomes smaller than the emission intensity E (TN) of the erasing light source at the time of TN, and the temperature of the stimulable phosphor plate is stored at the temperature of Tx. The erasing characteristic R (Tx) of the phosphor plate is the erasing characteristic R (Tn) of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tn.
(T) larger value ”.

The erasing light intensity E (TX) of the erasing light source when the environmental temperature is TX becomes larger than the luminous intensity E (TN) of the erasing light source when the environmental temperature is TN. , A fluorescent lamp and a xenon lamp are preferred examples, but are not limited thereto. In addition, “Emission intensity E (T
X) is the emission intensity E (T of the erasing light source when the environmental temperature is TN.
Light-emitting diodes and semiconductor lasers are preferred examples of the erasing light source having a smaller value than “N)”, but are not limited thereto.

The stimulable phosphor plate 12 is a plate having a stimulable phosphor. And the stimulable phosphor is
The latent image is formed by accumulating energy according to the radiation transmittance distribution of the subject with respect to the radiation dose from the radiation source. And as the stimulable phosphor,
It is preferably a stimulable phosphor.

The stimulable phosphor plate preferably has a stimulable phosphor layer provided on a support by vapor deposition or coating. The layer of the stimulable phosphor is preferably shielded or covered by a protective member in order to prevent adverse effects or damage due to the environment.

As a preferred stimulable phosphor,
For example, the following stimulable phosphors are exemplified, but not limited thereto.

[0041] [1] _{M'X · aM "X 2 · bM} '" X 5:
A stimulable phosphor represented by cA (where M 'is at least one kind of alkali metal selected from Li, Na, K, Rb and Cs. M "is B
e, Mg, Ca, Sr, Ba, Zn, Cd, Cu and N
It is at least one kind of divalent metal selected from i.
M ′ ″ is Sc, Y, La, Ce, Pr, Nd, Pm, S
m, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
It is at least one kind of trivalent metal selected from b, Lu, Al, Ga and In. X, X ₂ and X ₅ represent halogen. A is Eu, Tb, Ce, Tm, Dy, Pr, Ho,
Nd, Yb, Er, Gd, Sc, Lu, Sm, Y, T
It is at least one kind of metal selected from 1, Na, Ag, Cu and Mg. A is a numerical value in the range of 0 <a <0.5, 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. A specific example is described in JP-A-61-72087.

[2] (Ba _1-xy Mg _x Ca _y ) FX: e
A stimulable phosphor represented by Eu (where X is at least one of Br and Cl, and x, y and e are respectively 0 <x + y <0.6, 10
It is a number that satisfies ⁻⁶ ≦ e ≦ 5 × 10 ⁻² . A specific example is described in JP-A-55-12143.

[3] BaFX: a stimulable phosphor represented by xCe, yA (where X is at least one of ClBr and I,
A is at least one of In, Tl, Gd, Sm and Zn, and x and y are each 0 <x ≦ 2 × 10 ⁻¹
And 0 <y <5 × 10 ⁻² . A specific example is described in JP-A-55-84389.

[4] BaSO ₄ : A _x (where A is at least one of Dy, Tb and Tm, and x is a number satisfying 0.001 ≦ x ≦ 1) Examples are described in JP-A-48-80487.

[5] SrSO ₄ : A _x (where A is at least one of Dy, Tb and Tm, and x is a number satisfying 0.001 ≦ x ≦ 1) Examples are described in JP-A-48-80489.

[6] Li ₂ O. (B ₂ O ₂ ) _x : Cu (where x is a number satisfying 2 ≦ x ≦ 3) A specific example is described in JP-A-53-39277. It is described in the gazette.

[7] Li ₂ O. (B ₂ O ₂ ) _x : Cu, Au (where x is a number satisfying 2 ≦ x ≦ 3) A specific example is disclosed in No. 47883.

[8] SrS: Ce, Sm A specific example is described in US Pat. No. 3,859,527.

[0049]

[9] SrS: Eu, Sm A specific example is described in US Pat. No. 3,859,527.

[10] La ₂ O ₂ S: Eu, Sm A specific example is described in US Pat. No. 3,859,527.

[11] (Zn _1-x Cd _x ) S: A, X (where A is at least one kind of metal selected from Cu, Ag, Au and Mn. X represents halogen. X
Indicates a number satisfying 0 ≦ x ≦ 1. Incidentally, specific examples are described in U.S. Pat. No. 3,859,527 or JP-A-5-160078.

[12] (Zn _{1 -x} Cd _x ) S: A (where A is at least one metal selected from Cu, Ag, Au, Mn and Pb. X is 0 ≦ x ≦ 1
Indicates a number that satisfies Incidentally, specific examples are described in JP-A-55-12142 or JP-A-5-160078.

[13] Stimulable phosphor represented by MO.xSiO ₂ : A (where M is at least one kind of divalent metal selected from Mg, Ca, Sr, Ba, Zn and Cd). A is E
It is at least one metal selected from u, Tb, Ce, Tm, Pb, Tl, Bi and Mn. A is 0
<A <0.5, where x is 0.5 ≦ x ≦
It is a number that satisfies 2.5. A specific example is described in JP-A-55-12142.

[14] LnOX: stimulable phosphor represented by xA (where Ln is at least one kind of trivalent metal selected from Y, La, Gd and Lu. X is selected from Cl and Br) At least one type of halogen, wherein A is T
At least one metal selected from b and Ce. X is a number satisfying 0 <x <0.1. A specific example is described in JP-A-55-12144.

[15] Stimulable phosphor represented by (Ba _1-x M _x ) FX: yA (where X is at least one of I, Br and Cl, and A is In, Tl , Gd, Sm and Zr, where x and y are each 0 <x <0.
6, a number satisfying 0 ≦ y ≦ 0.2. A specific example is described in JP-A-55-12143.

[16] M "FX.xA: stimulable phosphor represented by cLn (where M" is Mg, Ca, Sr, Ba, Zn and Cd
At least one type of divalent metal selected from A is BeO, MgO, CaO, SrO, BaO, ZnO, A
l ₂ O ₂ , Y ₂ O ₂ , La ₂ O ₂ , Nd ₂ O ₂ , In ₂ O ₂ , Si
O ₂ , TiO ₂ , ZrO ₂ , GeO ₂ , SnO ₂ , ThO ₂ ,
It is at least one selected from Nb ₂ O ₅ and Ta ₂ O ₅ . X represents at least one halogen selected from I, Br and Cl. Ln is Eu, Tb, Ce, Tm, D
y, Pr, Ho, Nd, Yb, Er, Gd, Sc, L
u, Sm, Y, Tl, Na, Ag, Cu, and at least one metal selected from Mg. A is 0 <
a is a numerical value in the range of <0.5, 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. A specific example is described in JP-A-55-160078.

[17] A stimulable phosphor represented by xM ₃ (PO ₄ ) ₃ .NX ₃ .yA (where M and N are Mg, Ca, Sr, Ba,
It is at least one kind of divalent metal selected from Zn and Cd. X and X ₂ each represent at least one kind of halogen selected from F, Cl, Br and I. A is E
u, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Y
It is at least one metal selected from b, Er, Sb, Tl, Mn and Sn. Further, x is a number satisfying 0 <x ≦ 6, and y is a number satisfying 0 ≦ y ≦ 2. A specific example is described in JP-A-59-38278.

[18] A stimulable phosphor represented by M ₃ (PO ₄ ) ₃ .yA (where M is Mg, Ca, Sr, Ba, Zn and Cd
At least one type of divalent metal selected from A is Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Y
It is at least one metal selected from b, Er, Sb, Tl, Mn and Sn. Y is a number satisfying 0 ≦ y ≦ 2. A specific example is described in JP-A-59-38278.

[19] nReX ₃ .MAX ′ ₃ : stimulable phosphor represented by xEu (where Re is at least one selected from La, Gd, Y and Lu, and X and X ′ are F , Cl, Br and I
A is at least one alkaline earth metal selected from Ba, Sc and Ca, and x
Indicates a number satisfying 1 × 10 ⁻⁴ <x <3 × 10 ⁻¹ . n
And m are numbers satisfying 1 × 10 ⁻³ <n / m <7 × 10 ⁻¹ . A specific example is described in JP-A-59-155487.

[20] nReX ₃ .max ' ₃ : xEu,
Stimulable phosphor represented by ySm (where Re is at least one selected from La, Gd, Y and Lu, and X and X 'are F, Cl, Br and I
A is at least one alkaline earth metal selected from Ba, Sc and Ca, and x
And y are 1 × 10 ⁻⁴ <x <3 × 10 ⁻¹ and 1 respectively.
The number satisfies × 10 ^-4 <y <1 × 10 ^-1 . n and m
Indicates a number satisfying 1 × 10 ⁻³ <n / m <7 × 10 ⁻¹ . A specific example is described in JP-A-59-155487.

[21] MX · aMX ′ ₂ : stimulable phosphor represented by xEu (where M is at least one kind of divalent metal selected from Ca, Sr and Ba. X and X ′ are C different from each other
represents a halogen selected from l, Br and I. Also, a
Is a number satisfying 0.1 ≦ a ≦ 10, and x is 1 × 10 ⁻⁴
It is a number that satisfies ≦ x ≦ 1 × 10 ⁻² . Incidentally, specific examples are described in JP-A-60-84381 and JP-A-63-27588.

[22] Stimulable phosphor represented by BaX ₂ : Eu (X represents a halogen.) Specific examples are given in the 51st Annual Meeting of the Japan Society of Applied Physics (1990) Fall) (p. 1086).

As the stimulable phosphor having the erasing characteristic R (T) that increases as the temperature T increases, the following stimulable phosphor is particularly preferable.

[23] Rb (Br _x , I _1-x ): a stimulable phosphor represented by yTl (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁶ ≦ y ≦ 1 × 10 ⁻² . [24] BaF (Br _x , I _1-x ): a stimulable phosphor represented by yEu (where x is a number satisfying 0 ≦ x ≦ 1, and y is 1 × 1)
It is a number that satisfies 0 ⁻⁴ ≦ y ≦ 1 × 10 ⁻² . The temperature dependency of the erasing characteristic R (T) of the stimulable phosphor is determined by the erasable stimulable phosphor plate set by the device that irradiates the stimulable phosphor plate with erasing light from an erasing light source. Is the maximum temperature of Tx, the minimum temperature is Tn, the erasing characteristic R (Tx) of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tx, and the storability when the temperature of the stimulable phosphor plate is Tn. A value V represented by the following equation (1) when the erasing characteristic R (Tn) of the phosphor plate is used.
When p is 1.2 or more, the temperature dependence of the erasing characteristics of the stimulable phosphor is large, and the present invention is suitable. In particular, when p is 1.7 or more, it is suitable. And 10
The following is preferred.

Equation (1) logVp = log (R (Tx) / R (Tn)) × (4
0 / (Tx-Tn)) [23] Rb (Br _x , I _1-x ): RbBr ₂ which is an example of yTl: erase characteristic R (T) of 2 × 10 ⁻⁴ Tl
And [24] BaF (Br _x , I _1-x ): y
BaFI: an example of Eu: temperature dependence of the erase characteristic R (T) of 2 × 10 ⁻³ Eu, and [24] BaF (Br _x , I
_1-x ): BaF (Br _0.8 , an example of yEu)
I _0.2 ): FIG. 8 shows the temperature dependence of the erase characteristic R (T) of 1.5 × 10 ⁻³ Eu. The vertical axis indicates the erasing characteristic of the stimulable phosphor as a relative erasing characteristic obtained by standardizing the erasing characteristic at 25 ° C. as 1. Note that RbBr: T
At 1, Vp is about 2.3. BaFI: 2 ×
For 10 ⁻³ Eu, Vp is about 1.9. In addition, BaF
(Br _0.8 , I _0.2 ): In 1.5 × 10 ⁻³ Eu, Vp is about 1.5.

The material of the light emitting diode whose light emission intensity becomes smaller as the temperature becomes higher is GaP, GaP.
AsP / GaP and GaAlAs are preferred examples, but are not limited thereto. Then, the temperature dependence of the light emitting diode having an emission color of orange and red having a light emission wavelength of 600 nm or more is larger than that of the light emitting diode having an emission color of orange, red and light having a wavelength of 600 nm or more than that of a light emitting diode having a light emission wavelength of less than 600 nm. And, the emission wavelength is 600 nm or more and 770 nm.
The following light emitting diodes are preferred.

As for the temperature dependence of the light emission intensity of the light emitting diode, the maximum temperature of the environmental temperature set by the light emitting diode that irradiates the stimulable phosphor plate with the erasing light is defined as TX, and the minimum temperature is defined as TN. When the light emission intensity E (TX) of the light emitting diode when the environmental temperature is TX and the light emission intensity E (TN) of the light emitting diode when the environmental temperature is TN, Vl represented by the following equation (2) is 1.2 or more. Is particularly preferred for the effect of the present invention, and particularly preferably 1.7 or more. Moreover, it is desirable that it is 10 or less.

Equation (2) logVl = log (E (TX) / E (TN)) × (4
0 / (TX−TN)) FIG. 9 shows the temperature dependence of the light emission intensity of a light emitting diode whose material having a light emission wavelength of 660 nm is GaAlAs. The vertical axis represents the light emission intensity of the light emitting diode, 25
It is shown as relative illuminance normalized with the luminescence intensity at 1 ° C as 1. Note that Vl of this light emitting diode is about 2.0
And a plate provided with a stimulable phosphor layer represented by the chemical formula [23] or a plate provided with a stimulable phosphor layer represented by the chemical formula [24]. Can be used in good combination.

The material having an emission wavelength of 570 nm is GaP.
FIG. 10 shows the temperature dependence of the light emission intensity of the light emitting diode of FIG.
Shown in The vertical axis represents the light emission intensity of the light emitting diode,
It is shown as relative illuminance normalized by setting the luminescence intensity at 25 ° C. to 1. Note that Vl of this light emitting diode is about 1.2, and [25] BaF (Br _x , I _1-x ): yE
stimulable phosphor represented by u (where x is 0.6 ≦ x ≦ 1
And y is a number that satisfies 1 × 10 ⁻⁴ ≦ y ≦ 1 × 10 ⁻² . ) Can be used in good combination with a plate provided with a layer.

[0070]

EXAMPLES Examples of specific examples according to the present invention will be shown below as examples, but the present invention is not limited to these examples. Also,
Although the examples include certain expressions for terms and the like, they show preferred examples of the present invention, and do not limit the meaning or technical scope of the terms of the present invention.

Embodiment FIG. 1 is a schematic configuration diagram of a radiation image reading apparatus of this embodiment, FIG. 2 is a control block diagram of the radiation image reading apparatus of this embodiment,
3 is a perspective view of the radiation image reading device, FIG. 4 is a front view of the radiation image reading device, FIG. 5 is a left side view of the radiation image reading device, FIG. 6 is a diagram showing an optical system of a main scanning unit, and FIG. FIG. 5 is an explanatory diagram of the operation of the radiation image reading apparatus according to the present embodiment. The radiation image reading apparatus according to this embodiment will be described with reference to these drawings.

In this embodiment, the lateral direction of the apparatus main body 2 of the radiation image reading apparatus 1 is called an X direction, and the depth direction of the apparatus main body 2 of the radiation image reading apparatus 1 is called a Y direction. Therefore, the X direction and the Y direction are two directions orthogonal to each other in a horizontal plane, and the angle between the X direction and the Y direction is a right angle.

The radiation image reading apparatus 1 according to the present embodiment is configured such that the stimulable phosphor plate 12 is moved from the portable cassette 9 containing the flat stimulable phosphor plate 12 which has been subjected to X-ray photography.
Is a radiation image reading apparatus 1 that reads out a radiation image recorded on the stimulable phosphor plate 12. The apparatus main body 2 of the radiation image reading apparatus 1 of the present embodiment includes a cassette stacker 3, a plate holding unit 4, an image reading unit 5, a system control unit 6, an operation unit 7, and a power supply unit 8.

The cassette stacker 3 accommodates a plate-shaped stimulable phosphor plate 12 which has been radiographed, and has an opening formed on one side thereof.
A plurality of cassettes 9 from which the cassette 2 can be pulled out are arranged so that the stimulable phosphor plates 12 accommodated therein are substantially parallel to the plane formed by the vertical direction and the Y direction, and the positions in the X direction are different from each other. Can be set.

The cassette stacker 3 has a cassette stacker mechanism / drive unit 30 and a cassette stacker control unit 31. The cassette stacker control unit 31 receives the cassette stacker mechanism / drive based on a control signal from the system control unit 6. The driving unit 30 drives the cassette stacker 3 to take out the stimulable phosphor plate 12 from the cassette 9 set in the cassette stacker 3 or to accommodate the stimulable phosphor plate 12 in the cassette 9 set in the cassette stacker 3. Control.

The plate holding section 4 holds the cassette stacker 3
It is possible to take out and hold the stimulable phosphor plate 12 in a substantially vertical direction from any of the cassettes 9 set in the cassette.

The plate holding section 4 has a plate holding section mechanism / drive section 40 and a plate holding section control section 41. The plate holding section control section 41 includes a system control section 6
The plate holding mechanism / drive unit 40 takes out the stimulable phosphor plate 12 from the cassette 9 set in the cassette stacker 3 or stores the stimulable phosphor plate 12 in the cassette 9 set in the cassette stacker 3 based on the control signal from Control is performed so that the phosphor plate 12 is driven to be accommodated or moved in the X direction.

Further, the support frame 400 is supported by guide rails 401 and 402 arranged vertically on the blade holding mechanism / drive unit 40. The guide rails 401 and 402 are arranged in a direction orthogonal to the cassette 9 stored in the cassette stacker 3. The lower end of the support frame 400 is fixed to a transport belt 403 arranged below, and the transport belt 403 is driven by a transport motor 404, thereby
0 moves along the guide rails 401 and 402. The erasing unit 13 is attached to the upper part of the support frame 400.

The image reading section 5 has a sub-scanning section 50 and a main scanning section 51. The main scanning section 51 performs main scanning MS by laser light in the vertical direction, and reads a radiation image recorded on the stimulable phosphor plate 12 by laser scanning. The sub-scanning section 50 moves the main scanning section 51 in the Y direction to perform sub-scanning.

The system control unit 6 includes a main CPU 60,
The reading control unit 61, the system disk 62, the image disk 63, and the interface board (hereinafter, I / F)
Abbreviated as board. ) 65. And the main CPU
A CRT 70 of the operation unit 7 and a touch panel 71
And the read control unit 61 of the system control unit 6, the system disk 62, the image disk 63, and the I / F board 65.
And are connected.

The system disk 62 has a main CP
A system program for U60 to perform overall control, image processing, image transmission control, and image management is stored. The image disk 63 stores an image sent from the reading control unit 61 or stores an image that has been subjected to image processing.

The main CPU 60 stores the image sent from the reading control unit 61 and the processed image on the image disk 63 while developing the system program stored in the system disk 62 in the internal memory. While performing the reading and the reading of the image stored in the image disk 63, overall control, image processing, image transmission, and image management are performed.

The reading control unit 61 includes a cassette stacker control unit 31, a plate holding unit control unit 41, and a sub-scanning unit 5.
The main scanning unit 51 is controlled to read the radiation image recorded on the stimulable phosphor plate 12 by laser scanning, receives an image signal from the main scanning unit 51, and sends the read image to the main CPU 50.

The main CPU 60 is connected via an I / F board 65 to a host computer 66, a diagnostic device 67 and a patient registration terminal 68 outside the main unit 2. Then, the main CPU 60 controls the I / F
The image is transmitted to the host computer 66, the diagnostic device 67, and the patient registration terminal 68 via the board 65.

The operation unit 7 has a CRT 70 and a touch panel 71. The CRT 70 displays a display image transmitted from the main CPU 60, and
Sends to the main CPU 60 information relating to an instruction input entered by being touched by the operator.

The main CPU 60 performs overall control, image processing, image transmission, and image management based on the information on the instruction input sent from the touch panel 71 of the operation unit 7, and displays necessary information on the CRT 70 as appropriate. For this purpose, the display image is transmitted to the CRT 70.

When an instruction input including an instruction for designating one of the cassettes 9 set in the cassette stacker 3 is input from the operation unit 7, the system control unit 6 causes the plate holding unit 4 to switch from the operation unit 7. The stimulable phosphor plate 12 is taken out from the cassette 9 specified by the instruction input in the substantially vertical direction and held, and the image reading unit 5 reads the radiation image recorded on the stimulable phosphor plate 12 by laser scanning. And the image reading unit 5 that controls the plate holding unit 4 that holds the stimulable phosphor plate 12.

That is, as shown in FIG. 7, first, in the image reading section 5, the plate holding section 4 first moves the stimulable fluorescent light from the cassette 9 designated by the instruction input from the operation section 7 (S1). The body plate 12 is moved in the X direction to a position in the X direction at which the body plate 12 can be taken out in a substantially vertical direction. At this predetermined position in the X direction, the stimulable fluorescent light from the cassette 9 specified by the instruction input from the operation unit 7 is input. The body plate 12 is taken out and held in a substantially vertical direction, and the plate holding portion 4 is secondly (S2).
Is moved at least in the X direction and stopped at a predetermined position in the X direction. Thirdly, the plate holding unit 4 holding the stimulable phosphor plate 12 is fixed, and the image reading unit 5 is moved. Is moved in the Y direction, and the stimulable phosphor plate 12 is sub-scanned, whereby the image reading section 5 is moved.
Reads a radiation image recorded on the stimulable phosphor plate 12 held by the plate holding unit 4. Then, in the fourth (S4), the image reading unit 5 moves the plate holding unit 4
When reading of the radiation image recorded on the stimulable phosphor plate 12 held in the storage unit is completed, the plate holding unit 4 is set on the cassette stacker 3 in which the held stimulable phosphor plate 12 is stored. X to a predetermined X-direction position where the stimulable phosphor plate 12 can be transported and accommodated in the cassette 9 in a substantially vertical direction.
The stimulable phosphor plate 12 holding the stimulable phosphor plate 12 in which the radiation image is read by the image reading unit 5 is moved to the cassette 9 in which the stimulable phosphor plate 12 is accommodated.
Is transported in a substantially vertical direction and accommodated.

Then, the plate holding unit 4 replaces the storable phosphor plate 12 holding the radiation image read by the image reading unit 5 with the storable phosphor plate 12.
When the erasing section 13 transports and accommodates the cassette 9 in the cassette 9 in which the stimulable phosphor plate 1 has been accommodated in a substantially vertical direction.
By irradiating an erasing light from an erasing light source to 2, an afterimage remaining on the stimulable phosphor plate 12 from which the radiation image has been read by the image reading unit 5 is deleted.

As a result, since the stimulable phosphor plate 12 can be accommodated in the cassette 9 and the residual image remaining on the stimulable phosphor plate 12 can be erased at the same time, the cycle time for image reading can be shortened. can do.

The stimulable phosphor plate 12 has a stimulable phosphor layer, and the stimulable phosphor accumulates energy in accordance with the radiation transmittance distribution of the object with respect to the irradiation radiation amount from the radiation source. This is a layer of a stimulable phosphor which is a kind of a stimulable phosphor that forms a latent image. The stimulable phosphor plate 12 is provided with a stimulable phosphor layer by vapor deposition. The stimulable phosphor layer is shielded by a protective member to prevent adverse effects and damage due to the environment. As the stimulable phosphor, a stimulable phosphor whose material shows the temperature dependence of the erasing characteristic in FIG. 8 is RbBr ₂ : Tl.

The erasing light source of the erasing section 13 is made of GaAs having a light emission wavelength of 660 nm as shown in FIG.
A light emitting diode of 1 As is used, and the moving speed of the stimulable phosphor plate 12 during erasing is 25 mm / sec.
However, it can be changed according to the image recording of the stimulable phosphor plate 12.

The erasing light source of the erasing section 13 is intermittently pulsed. The frequency of this pulse drive is 1
Since it is about kHz and the duty ratio is about 70%,
In particular, afterimages remaining on the stimulable phosphor plate 12 can be favorably erased.

The image reading section 5 is built in the apparatus main body 2 of the radiation image reading apparatus 1 and is arranged below the operation section 7. Sub-scanning unit 50 provided in image reading unit 5
Transports the main scanning unit 51 in the sub-scanning direction.

As shown in FIGS. 4, 5 and 6, the sub-scanning section 50 has a guide shaft 500 facing the stimulable phosphor plate 12 and a ball screw 501 arranged in parallel. The guide shaft 500 is located at the top, and the ball screw 50
1 is located below, and the guide shaft 500 and the ball screw 5
01, the main scanning unit 51 is held vertically and can be moved horizontally.

The ball screw 501 is provided with a direct drive motor 502.
02 drives the ball screw 501 to move the main scanning unit 51 in the sub-scanning direction.

As shown in FIG. 6, the main scanning section 51 includes a laser beam generating section 510, a polygon mirror 511,
Lens, reflection mirror 513, light receiving section 51 constituting
4 and the like are integrally formed. Laser beam generator 51
0 has a gas laser solid laser, a semiconductor laser, or the like as a light source. The laser beam generator 510 generates a laser beam whose emission intensity is forced as excitation light.

The laser beam reaches the polygon mirror 511 via the optical system, is deflected there, is condensed by the fθ lens constituting the condensing body 512, and is reflected by the reflection mirror 51.
The light path is deflected by 3 and is guided to the stimulable phosphor plate 12 as a scanning light for stimulating excitation. An image is read by receiving photostimulated light emitted by the stackable phosphor plate 12 scanned by the laser beam by the light receiving unit 514. Light receiving section 51
4 includes a long photomultiplier 514a and a flat light collector 514b.

The light enters the long photomultiplier 514a and is photoelectrically converted into an electric signal corresponding to the incident light. That is, the stimulated emission enters the long photomultiplier 514a via the flat light condensing body 514b and is photoelectrically converted, so that an output current corresponding to a radiation image is obtained. The output current from the long photomultiplier 514a is converted into a voltage signal by a current / voltage converter (not shown) inside the reading control unit 61, and is amplified by an amplifier (not shown).
It is converted to a digital image signal by a D converter. The digital image signals are sequentially output to the main CPU 60,
After being subjected to various image processing such as gradation processing, the image data is stored as it is on the image disk 63, or
It is displayed at T70.

The reading controller 61 includes a polygon mirror 51
1 and various origin synchronizing signals and an origin position detection signal from a photo sensor (not shown) for detecting a sub-scanning start position.
1 from the start position while synchronizing with the main scanning by the main scanning unit 5
1 is moved at a predetermined speed in the sub-scanning direction.

The radiation image reading apparatus of this embodiment is
It may be used as a radiation image erasing device for erasing the residual image remaining on the stimulable phosphor plate from which a radiation image has been read by another radiation image reading device. In this case, first, as shown in S1 of FIG. 7, the image reading unit 5 causes the plate holding unit 4 to move the stimulable phosphor plate 12 from the cassette 9 specified by the instruction input from the operation unit 7 in a substantially vertical direction. The stimulable phosphor plate 12 is moved from the cassette 9 specified by the instruction input from the operation unit 7 in the substantially vertical direction to the predetermined X-direction position at which the stimulable phosphor plate 12 can be taken out. The stimulable phosphor plate 12 is then taken out of the stimulable phosphor plate 1 and held.
The residual image remaining on the stimulable phosphor plate 12 is erased by the erasing light from the erasing light source of the erasing unit 6 while being conveyed and housed in the cassette 9 in which the housing 2 has been housed in a substantially vertical direction.

[0102]

According to the present invention, regardless of the temperature of the erased portion,
Afterimages remaining on the stimulable phosphor plate can be sufficiently erased.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a radiation image reading apparatus according to an embodiment.

FIG. 2 is a control block diagram of the radiation image reading apparatus according to the embodiment.

FIG. 3 is a perspective view of the radiation image reading apparatus according to the embodiment.

FIG. 4 is a front view of the radiation image reading apparatus according to the embodiment.

FIG. 5 is a left side view of the radiation image reading apparatus according to the embodiment.

FIG. 6 is a diagram illustrating an optical system of a main scanning unit of the radiation image reading apparatus according to the embodiment.

FIG. 7 is an operation explanatory view showing that the plate holding unit 4 of the radiation image reading apparatus of the embodiment is fixed and the image reading unit 5 is moved in the Y direction to perform sub-scanning.

FIG. 8 shows the temperature dependence of the erasing characteristic R (T) of RbBr ₂ : Tl, the temperature dependence of the erasing characteristic R (T) of BaFI: Eu, and the erasing characteristic of BaF (Br _0.5 , I _0.5 ): Eu. R
The figure which shows the temperature dependence of (T). The vertical axis indicates the erasing characteristic of the stimulable phosphor as a relative erasing characteristic obtained by standardizing the erasing characteristic at 25 ° C. as 1.

FIG. 9 is a diagram showing the temperature dependence of the light emission intensity of a light emitting diode whose material having a light emission wavelength of 660 nm is GaAlAs. The vertical axis indicates the light emission intensity of the light emitting diode as relative illuminance normalized with the light emission intensity at 25 ° C. being 1.

FIG. 10 is a diagram showing the temperature dependence of the light emission intensity of a light emitting diode whose material having a light emission wavelength of 570 nm is GaP. In addition,
The vertical axis indicates the light emission intensity of the light emitting diode as relative illuminance normalized with the light emission intensity at 25 ° C. being 1.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 radiation image reading device 2 device main body 3 cassette stacker 4 plate holding unit 5 image reading unit 6 system control unit 7 operation unit 8 power supply unit 9 cassette 12 stimulable phosphor plate 13 erasing unit

Claims (15)

[Claims] 1. A radiation image erasing method for irradiating an erasing light from an erasing light source to a stimulable phosphor plate from which a radiation image has been read, wherein the luminous intensity of the erasing light source depends on the temperature of the stimulable phosphor plate. A radiation image erasing method characterized in that the erasing characteristic is inverse to the temperature dependence of the erasing characteristic. 2. The stimulable phosphor plate has a characteristic that the higher the temperature, the easier the erasure is. The erasable storage is set by an apparatus that irradiates the stimulable phosphor plate with erasing light from an erasing light source. Tx is the maximum temperature of the phosphor plate
Where Tn is the minimum temperature, TX is the maximum environmental temperature set by the erasing light source that irradiates the stimulable phosphor plate with erasing light, and TX is the environmental temperature when the minimum temperature is TN. Intensity E (TX) of the erasing light source at
Is a value smaller than the emission intensity E (TN) of the erasing light source when the environmental temperature is TN, and the erasing characteristic R of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tx.
2. The radiation image erasing method according to claim 1, wherein (Tx) is such that the temperature of the stimulable phosphor plate becomes larger than the erasing characteristic R (Tn) of the stimulable phosphor plate at Tn. . 3. The radiation image according to claim 2, wherein the stimulable phosphor plate is a plate provided with a stimulable phosphor layer represented by the following chemical formula [23]. Erase method. [23] Rb (Br _x , I _1-x ): yTl (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁶ ≦ y ≦ 1 × 10 ⁻² . ) 4. The radiation image according to claim 2, wherein the stimulable phosphor plate is a plate provided with a layer of a stimulable phosphor represented by the following chemical formula [24]. Erase method. [24] BaF (Br _x , I _1-x ): yEu (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁴ ≦ y ≦ 1 × 10 ⁻² . ) 5. The radiation image erasing method according to claim 2, wherein the erasing light source is a light emitting diode. 6. A radiation image erasing apparatus having an erasing section for irradiating an erasing light from an erasing light source to a stimulable phosphor plate from which a radiation image has been read, wherein the temperature dependence of the emission intensity of the erasing light source is such that A radiation image erasing apparatus characterized in that the erasing characteristics of the luminescent phosphor plate are opposite to the temperature dependence. 7. The erasable storage set in a device for irradiating the stimulable phosphor plate with erasing light from an erasing light source, wherein the stimulable phosphor plate has a characteristic of being easily erased as the temperature is high. Tx is the maximum temperature of the phosphor plate
Where Tn is the minimum temperature, TX is the maximum environmental temperature set by the erasing light source that irradiates the stimulable phosphor plate with erasing light, and TX is the environmental temperature when the minimum temperature is TN. Intensity E (TX) of the erasing light source at
Is a value smaller than the emission intensity E (TN) of the erasing light source when the environmental temperature is TN, and the erasing characteristic R of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tx.
7. The radiation image erasing apparatus according to claim 6, wherein (Tx) is such that the temperature of the stimulable phosphor plate is larger than the erasing characteristic R (Tn) of the stimulable phosphor plate at Tn. . 8. The radiation image according to claim 7, wherein the stimulable phosphor plate is a plate provided with a layer of a stimulable phosphor represented by the following chemical formula [23]. Erasing device. [23] Rb (Br _x , I _1-x ): yTl (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁶ ≦ y ≦ 1 × 10 ⁻² . ) 9. The radiation image according to claim 7, wherein the stimulable phosphor plate is a plate provided with a layer of a stimulable phosphor represented by the following chemical formula [24]. Erasing device. [24] BaF (Br _x , I _1-x ): yEu (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁴ ≦ y ≦ 1 × 10 ⁻² . ) 10. The radiation image erasing apparatus according to claim 7, wherein the erasing light source is a light emitting diode. 11. A stimulable phosphor plate on which a radiation image is accumulated and recorded is irradiated with excitation light, and stimulated emission is detected.
An image reading unit that reads the radiation image stored and recorded on the stimulable phosphor plate, and erasing that irradiates erasing light from an erasing light source to the stimulable phosphor plate that has read the radiation image by the image reading unit. A radiation image reading apparatus, wherein the temperature dependence of the emission intensity of the erasing light source is opposite to the temperature dependence of the erasing characteristic of the stimulable phosphor plate. apparatus. 12. The erasable storage set in a device for irradiating the stimulable phosphor plate with erasing light from an erasing light source, wherein the stimulable phosphor plate has a characteristic of being easily erased as the temperature is high. The maximum temperature of the phosphor plate is T
x, the minimum temperature is Tn, and the maximum temperature of the environmental temperature set by the erasing light source for irradiating the stimulable phosphor plate with the erasing light is TX, and when the minimum temperature is TN, the environmental temperature is Emission intensity E (TX) of the erasing light source at TX
Is a value smaller than the emission intensity E (TN) of the erasing light source when the environmental temperature is TN, and the erasing characteristic R of the stimulable phosphor plate when the temperature of the stimulable phosphor plate is Tx.
The radiation image reading apparatus according to claim 11, wherein (Tx) is such that the temperature of the stimulable phosphor plate becomes a value larger than the erasing characteristic R (Tn) of the stimulable phosphor plate at Tn. . 13. The radiation image according to claim 12, wherein the stimulable phosphor plate is a plate provided with a stimulable phosphor layer represented by the following chemical formula [23]. Reader. [23] Rb (Br _x , I _1-x ): yTl (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁶ ≦ y ≦ 1 × 10 ⁻² . ) 14. The radiation image according to claim 12, wherein the stimulable phosphor plate is a plate provided with a stimulable phosphor layer represented by the following chemical formula [24]. Reader. [24] BaF (Br _x , I _1-x ): yEu (where x is a number satisfying 0 ≦ x ≦ 1 and y is 1 × 1)
It is a number that satisfies 0 ⁻⁴ ≦ y ≦ 1 × 10 ⁻² . ) 15. The radiation image reading apparatus according to claim 12, wherein the erasing light source is a light emitting diode.