JP2002189264A - Radiation image information reader and reading unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the adjustment and exchange work of relative positional relations of a radiation image information reader having a light source, exciting light condenser lens and line sensor. SOLUTION: This radiation image information reader has a light source section 11 which emits exciting light 10 to excite a stimulable phosphor sheet 40 in which radiation image information is accumulated and recorded, the exciting light condenser lens 12 which converges the exciting light 10 in a linear form on the stimulable phosphor sheet 40, the line sensor 14 which detects the stimulated luminous light 41 emitted form the portion linearly irradiated with the exciting light of the stimulable phosphor sheet 40 and vertical scanning means 33 and 34 which moves one of the light source 11, the exciting light condenser lens 12, the line sensor 14 and the stimulable phosphor sheet 40 relatively with respect to the other in a direction crossing with the longitudinal direction of the portions irradiated with the exciting light. The light source 11, the exciting light condensing lens 12 and the light sensor 14 are integrally fixed to a holding member 15 by maintaining the prescribed relative positional relations to each other and a casing 30 for vertical scanning is freely movably fitted with this holding member 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of irradiating a stimulable phosphor sheet on which radiation image information is stored with excitation light, and photoelectrically reading stimulated emission light emitted from the sheet. More specifically, the present invention relates to a radiation image information reading apparatus for obtaining an image signal indicating the radiation image, and more particularly, to irradiating a stimulable phosphor sheet linearly with excitation light, and then irradiating the stimulable phosphor sheet from a linear excitation light irradiated portion of the sheet. The present invention relates to a radiation image information reading device that detects emitted stimulated emission light with a line sensor.

[0002] The present invention also relates to a reading unit constituting such a radiation image information reading apparatus.

[0003]

2. Description of the Related Art Conventionally, when a radiation is irradiated, a part of the radiation energy is accumulated, and then, when an excitation light such as a visible light or a laser light is irradiated, a storage light which shows a stimulated emission according to the accumulated radiation energy. Phosphor (stimulable phosphor)
A radiation image recording / reproducing system using a stimulable phosphor sheet obtained by laminating the stimulable phosphor on a support is widely used.

This radiation image recording / reproducing system irradiates the stimulable phosphor sheet with radiation transmitted through a subject such as a human body, and accumulates and records radiation image information of the subject on the stimulable phosphor sheet. The sheet is two-dimensionally scanned with excitation light such as laser light to generate stimulated emission light from the excitation light irradiated portion, and the stimulated emission light is read by photoelectric reading means to indicate the radiation image information. An image signal is obtained (for example, see JP-A-55-12429,
55-116340, 56-104645, etc.).

[0005] The image signal obtained by this system is subjected to image processing such as gradation processing and frequency processing suitable for observation and interpretation, and a radiation image carried by the signal is converted into a visible image for diagnosis on a film. Playback recording or CR
It is used for displaying on a T image display device or the like. In addition,
When the stimulable phosphor sheet after reading the radiation image information is irradiated with erasing light and the remaining energy is released, the sheet is ready to store and record the radiation image information again and can be used repeatedly. Will be possible.

Further, in order to improve the detection quantum efficiency in radiation image formation, that is, the radiation absorptivity, the photostimulated luminous efficiency, and the extraction efficiency of the photostimulated luminescent light, the radiation absorbing function and the energy storage of the conventional stimulable phosphor sheet are improved. A new type of stimulable phosphor sheet which is separated from the function has also been proposed (Japanese Patent Application No. 11-372978).

The stimulable phosphor sheet is capable of absorbing light in the ultraviolet to visible region and storing its energy, and emits the energy as photostimulated light when excited by light in the visible to infrared region. It contains a stimulable phosphor layer dedicated to storage.

[0008] This new type of stimulable phosphor sheet preferably has a form in which a radiation absorbing phosphor layer containing a phosphor that absorbs radiation and emits light in the ultraviolet to visible region is added. In that case, the energy of light in the ultraviolet to visible region (which corresponds to the radiation image information) emitted from the radiation absorbing phosphor layer when the radiation having the image information is irradiated is stimulated by the radiation. Is accumulated in the layer of the luminescent phosphor. Then, if the stimulable phosphor sheet is thereafter scanned with excitation light, stimulable luminescent light indicating radiation image information is emitted from the stimulable phosphor layer.

This new type of stimulable phosphor sheet may be formed without the radiation absorbing phosphor layer described above. In this case, the stimulable phosphor sheet is used in combination with a phosphor screen having a radiation-absorbing phosphor layer containing a phosphor that absorbs radiation and emits light in the ultraviolet to visible region.

That is, when the phosphor screen is irradiated with radiation while the phosphor screen is in close contact with the stimulable phosphor sheet, light in the ultraviolet to visible region emitted from the radiation-absorbing phosphor layer of the phosphor screen can be obtained. Energy (which corresponds to the radiation image information) is stored in the stimulable phosphor layer of the stimulable phosphor sheet. Therefore, also in this case, if the stimulable phosphor sheet is thereafter scanned with the excitation light, the stimulable phosphor layer emits stimulable emission light indicating radiation image information.

Here, in the radiation image information reading apparatus used in the above-mentioned radiation image recording and reproducing system,
In order to shorten the reading time of the stimulated emission light, and to reduce the size and cost of the apparatus, the excitation light is applied linearly to the stimulable phosphor sheet, and a line composed of a CCD or the like is used as the photoelectric reading means. It has been proposed to apply a sensor (JP-A-60-111568, JP-A-60-236354,
JP-A No. 1-101540).

A radiation image information reading apparatus of this kind basically includes a light source for emitting excitation light for exciting a stimulable phosphor sheet on which radiation image information is stored and stored, and an excitation light emitted from the light source for storing the excitation light. An excitation light condensing lens that linearly converges on the phosphor sheet, and a plurality of photoelectric conversion elements are juxtaposed along the linear excitation light irradiation portion of the stimulable phosphor sheet. A line sensor that detects stimulated emission light emitted from the irradiated portion, a light source, an excitation light condensing lens and a line sensor, and one of the stimulable phosphor sheets relative to the other, the excitation light And a sub-scanning means for moving in a direction intersecting with the length direction of the irradiated portion.

[0013]

In the radiation image information reading apparatus having the above structure, it is necessary to dispose and fix the light source, the excitation light focusing lens and the line sensor in a state of maintaining a predetermined relative positional relationship with each other. However, in the conventional apparatus, since they are individually fixed to the sub-scanning casing, when replacing one of them with a new one in the event of a failure or maintenance, it is necessary to maintain a predetermined relative positional relationship with each other. It is difficult to adjust the position with high accuracy, and the replacement work is also troublesome.

The above-described sub-scanning casing is a casing which is relatively movable with respect to the stimulable phosphor sheet, and is fixed in the radiation image information reading apparatus so that the stimulable phosphor sheet is sub-scanned. It may be moved, or conversely, the stimulable phosphor sheet may be fixed and the sub-scanning case may be sub-scanned.

The present invention has been made in view of the above circumstances, and when replacing any one of the light source, the excitation light condensing lens, and the line sensor, adjustment of the relative positional relationship between the light source, the excitation light condensing lens, and the exchange operation is facilitated. It is an object of the present invention to provide a radiographic image information reading apparatus that can be performed in a timely manner.

Another object of the present invention is to provide a reading unit that can constitute such a radiation image information reading apparatus.

[0017]

As described above, a radiation image information reading apparatus according to the present invention comprises: a light source which emits excitation light for exciting a stimulable phosphor sheet on which radiation image information is stored; An excitation light condensing lens that linearly converges the emitted excitation light on the stimulable phosphor sheet, and a plurality of photoelectric conversion elements along the linear excitation light irradiation portion of the stimulable phosphor sheet. Are arranged side by side, and a line sensor for detecting stimulated emission light emitted from the excitation light irradiation part, the light source, the excitation light condensing lens and the line sensor, and one of the stimulable phosphor sheet are used. A radiation image information reading apparatus comprising: a sub-scanning means for moving the excitation light irradiation portion in a direction intersecting with the length direction of the excitation light irradiation part. The holding member is integrally fixed to a holding member while maintaining a predetermined relative positional relationship with each other, and the holding member is mounted on a sub-scanning casing which is relatively moved with the stimulable phosphor sheet for excitation light sub-scanning. It is characterized by being detachably attached.

In the case where a stimulating luminescent light condensing lens for collecting stimulating luminescent light emitted from a linear excitation light irradiated portion of the stimulable phosphor sheet and guiding the stimulable luminescent light to a line sensor is provided,
The stimulated emission light condensing lens is also desirably fixed to the holding member while maintaining a predetermined relative positional relationship with the light source, the excitation light condensing lens, and the line sensor.

Further, in the above configuration, more preferably, an amplifier for amplifying the output of the line sensor, particularly an amplifier such as a preamplifier, or an A / D converter for A / D converting the output of the line sensor.
The / D converter is also fixed to the holding member.

On the other hand, a reading unit according to the present invention is a reading unit constituting a radiation image information reading apparatus including the above-described light source, excitation light focusing lens, line sensor, and sub-scanning means. The light source, the excitation light condensing lens and the line sensor are fixed to each other on a holding member that is detachably attached to a sub-scanning casing that is relatively moved with the stimulable phosphor sheet for excitation light sub-scanning. They are integrally held while maintaining the relative positional relationship.

[0021]

According to the radiation image information reading apparatus of the present invention, the light source, the excitation light condensing lens and the line sensor are integrally fixed to the holding member while maintaining a predetermined relative positional relationship with each other. Since it is detachably attached to the sub-scanning casing that moves relative to the stimulable phosphor sheet for excitation light sub-scanning, replace the light source, excitation light focusing lens, or line sensor with a new one. In this case, remove the holding member from the sub-scanning housing,
Instead, a holding member holding the new light source, the excitation light focusing lens, and the line sensor may be attached to the sub-scanning housing.

If the light source, the excitation light condensing lens or the line sensor can be replaced in such a form, it is not necessary to adjust the relative positional relationship at the installation site of the radiation image information reading apparatus, and the replacement operation itself is extremely easy. It becomes something.

Adjustment of the relative positional relationship between the light source, the excitation light condenser lens and the line sensor can be performed when fixing them to a holding member in a factory or the like. In factories, etc., compared to the installation site of a radiation image information reading device, there are generally more abundant equipment and jigs for adjusting the mounting position of optical components. It can be done more easily than at the installation site and the operating costs are reduced.

It is to be noted that the stimulated emission light condensing lens comprises the above light source,
If the excitation light condenser lens and the line sensor are fixed to the holding member while maintaining a predetermined relative positional relationship, when exchanging the stimulated emission light condenser lens with a new one, the same as described above. The effect of is obtained.

Further, an amplifier for amplifying the output of the line sensor and an output of the line sensor to the A / D
If the A / D converter to be converted is also fixed, the wiring of those wirings is shortened, so that an effect of reducing noise mixed into the read signal of the radiation image information from the wirings can be obtained.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 respectively
FIGS. 3 and 4 show the front shape and side shape of a radiation image information reading apparatus using the reading unit 1 according to an embodiment of the present invention. It is shown.

First, the reading unit 1 shown in FIGS. 1 and 2 will be described. As shown in the figure, the reading unit 1 includes a laser diode 11 for emitting a laser beam 10 as excitation light, and a laser beam emitted in a divergent light state.
A cylindrical lens 12 as an excitation light condensing lens for condensing the light 10 only in the plane shown in FIG. 2 and a stimulable luminescence light condensing lens for condensing stimulable light described later only in the plane shown in FIG. A cylindrical lens 13 and a CCD line sensor 14 for detecting the stimulated emission light are integrally fixed to a holding member 15.

The CCD line sensor 14 includes a plurality of photoelectric conversion elements (sensor chips) in a direction orthogonal to the plane of FIG.
Are juxtaposed. An excitation light cut filter 16 is attached to the light receiving surface of the CCD line sensor 14.

The laser diode 11, the cylindrical lenses 12, 13 and the CCD line sensor 14 are fixed to a holding member 15 while maintaining a predetermined relative positional relationship with each other. The predetermined relative positional relationship will be described later.

In the present embodiment, in particular, a preamplifier (preamplifier) 17 for amplifying the output of the CCD line sensor 14 and an A / D for A / D converting the output of the CCD line sensor 14 amplified by the preamplifier 17 are provided. The converter 18 is also fixed to the holding member 15. The preamplifier 17 is a cable
It is electrically connected to the CCD line sensor 14 via 19. On both left and right sides of the holding member 15, mounting members 20 each having a not-shown bolt hole or mounting reference surface are fixed.

Next, the radiation image information reading apparatus shown in FIGS. 3 and 4 will be described. This radiation image information reading apparatus has a sub-scanning casing 30, and the reading unit 1 is attached to the sub-scanning casing 30. This attachment is performed, for example, by fixing the attachment member 20 of the reading unit 1 to the reading unit attachment portion 31 of the sub-scanning housing 30 with the bolt 32. Therefore, after this installation
The reading unit 1 can be removed from the sub-scanning casing 30 by loosening and removing the reading unit 32. The reading unit 1 is fixed at a predetermined position with respect to the sub-scanning housing 30 by, for example, matching the reference surfaces of the mounting member 20 and the reading unit mounting portion 31.

In the sub-scanning housing 30, two pairs of conveying rollers 33 and 34, which are sub-scanning means, and guide plates 35, 36 and 37 are provided. The transport roller pair 33 includes a driving roller 33a and a driven roller 33b that is pressed against and driven by the driving roller 33a. The transport roller pair 34 is also a drive roller 34
a and a driven roller 34b that is pressed against and driven by the driven roller 34b.

Hereinafter, the operation of the radiation image information reading apparatus having the above configuration will be described. The stimulable phosphor sheet 40 in which the radiation image information of the subject is accumulated and recorded by irradiating the subject with radiation, etc., is sent forward (leftward in FIG. 4) over the guide plate 35 by a conveying means (not shown). .

When the leading end of the stimulable phosphor sheet 40 is sandwiched between the drive roller 33a and the driven roller 33b of the transport roller pair 33, the stimulable phosphor sheet 40 is thereafter moved by the guide plate by the transport roller pair 33. It is fed at a constant speed over 35 and 36 in the arrow Y direction (sub-scanning direction) in FIG. In this way, the stimulable phosphor sheet 40 is fed at a constant speed and its tip is sandwiched between the drive roller 34a and the driven roller 34b of the transport roller pair 34. , And is fed over the guide plates 35, 36 and 37 at a constant speed.

When the stimulable phosphor sheet 40 is fed at a constant speed as described above, the laser diode 11 of the reading unit 1 is driven, and the laser beam 10 emitted therefrom irradiates the stimulable phosphor sheet 40. Is done. This laser beam
4 is condensed by the cylindrical lens 12 only in the plane shown in FIG. 4, thereby becoming a fan beam, converging on the stimulable phosphor sheet 40 and irradiating the sheet 40 in a linear manner.

The linear irradiation portion of the laser beam 10 on the stimulable phosphor sheet 40 extends in the direction of arrow X in FIG. And are orthogonal.

From the portion of the stimulable phosphor sheet 40 which has been irradiated with the laser beam 10, a stimulating luminescent light 41 of an amount corresponding to the radiation image information stored and recorded diverges. For example, this blue stimulating light 41 is a cylindrical lens
The light is condensed in the plane shown in FIG. 4 by 13 and guided to the CCD line sensor 14, and is photoelectrically detected by the CCD line sensor 14. The laser beam reflected by the stimulable phosphor sheet 40 and traveling toward the CCD line sensor 14
10 is cut by the excitation light cut filter 16.

The CCD line sensor 14 outputs an analog light detection signal corresponding to the amount of the stimulating light 41 (that is, indicating radiation image information). This light detection signal is
The signal is input to the preamplifier 17 via the amplifier 19, amplified there, and converted into a digital image signal D by the A / D converter 18.

This digital image signal D is subjected to image processing such as gradation processing in an image processing device (not shown), and is also sent to an image reproducing device (not shown) to be recorded on the stimulable phosphor sheet 40. It is used for reproduction of the radiation image.
The image reproducing device may be a display unit such as a CRT display device or a recording device for performing optical scanning recording on a photosensitive film.

As is clear from the above description, the holding member 15 has the laser diode 11, the cylindrical lens 12,
13 and the CCD line sensor 14 are fixed in a relative positional relationship such that the laser beam 10 and the stimulated emission light 41 are in the state shown in FIG. That is, under this relative positional relationship, the linear irradiation portion of the laser beam 10 on the stimulable phosphor sheet 40 is present on the optical axis of the cylindrical lens 13 and the CCD line sensor 14.

In this radiation image information reading apparatus,
The laser diode 11, the cylindrical lenses 12, 13 and the CCD line sensor 14 are integrally fixed to a holding member 15 while maintaining a predetermined relative positional relationship with each other.
Is detachably attached to the sub-scanning housing 30, so that the laser diode 11, the cylindrical lens 12,
When replacing the 13 or the CCD line sensor 14 with a new one, remove the holding member 15 from the sub-scanning casing 30 and hold the new laser diode 11, the cylindrical lenses 12, 13 and the CCD line sensor 14 instead. The holding member 15 may be attached to the sub-scanning housing 30.

In such a form, the laser diode 11, the cylindrical lenses 12, 13 or the CCD line sensor
If 14 can be replaced, there is no need to adjust the relative positional relationship at the installation site of the radiation image information reading apparatus, and the replacement operation itself is extremely easy.

The relative positional relationship between the laser diode 11, the cylindrical lenses 12, 13 and the CCD line sensor 14 can be adjusted when fixing them to the holding member 15 at a factory or the like. In factories, etc., compared to the installation site of a radiation image information reading device, there are generally abundant equipment and jigs for adjusting the mounting position of optical components. It can be done more easily than at the installation site, and the operating cost is lower.

Further, in the embodiment, since the preamplifier 17 and the A / D converter 18 are also fixed to the holding member 15, it is only necessary to provide the cable 19 for the wiring, and the wiring is short and simplified. Is done. Thus, in the present apparatus, an effect of reducing noise mixed into the read signal of the radiation image information from the wiring can be obtained.

The stimulable phosphor sheet to be read by the radiation image information reading apparatus of the present invention may be a stimulable phosphor sheet having both a radiation absorbing function and an energy storing function, or The above-mentioned Japanese Patent Application No. 11-3 was provided with a phosphor layer dedicated to storage to separate both functions.
It may be the stimulable phosphor sheet disclosed in 72978. When the stimulable phosphor sheet provided with the phosphor layer dedicated to storage is used, the detection quantum efficiency in radiation image formation, that is, the radiation absorptance, the stimulated emission efficiency, and the efficiency of taking out the stimulated emission light are generally increased. Therefore, the image quality of the reproduced radiation image can be improved.

Further, the stimulable phosphor sheets to be read have radiation energy absorption characteristics different from each other.
A stimulable phosphor for radiation energy subtraction, which has two stimulable phosphor layers and can radiate two types of stimulated emission light carrying the radiation image information recorded in each layer from the front and back surfaces of the sheet. It may be a body sheet.

In this case, the radiation image information reading apparatus of the present invention may be provided with a reading unit similar to the reading unit 1 used in the above embodiment on both sides of the stimulable phosphor sheet.

The above-mentioned stimulable phosphor sheet for radiation energy subtraction has a structure in which, for example, an excitation light-reflecting partition member extending in the thickness direction of the sheet is subdivided into a number of micro-chambers. Oriented stimulable phosphor sheets can also be used.

Further, in the above-described embodiment, the stimulable phosphor sheet 40 is transported to the conveying roller pair for the excitation light sub-scanning.
Although it is conveyed at a constant speed by 33 and 34, the means for sub-scanning the excitation light is not limited to such a means, and for example, a means for conveying the stimulable phosphor sheet 40 by an endless belt, or a fixed accumulation It is also possible to apply a device that moves the sub-scanning housing 30 to which the reading unit 1 is attached relative to the luminescent phosphor sheet 40.

[Brief description of the drawings]

FIG. 1 is a front view of a reading unit according to one embodiment of the present invention.

FIG. 2 is a side view of the reading unit.

FIG. 3 is a front view of a radiation image information reading apparatus using the reading unit.

FIG. 4 is a side view of the radiation image information reading apparatus.

[Explanation of symbols]

 1 Reading unit 10 Laser beam (excitation light) 11 Laser diode 12 Cylindrical lens (excitation light condensing lens) 13 Cylindrical lens (stimulated emission light condensing lens) 14 CCD line sensor 15 Holding member 16 Excitation light cut filter 17 Preamplifier 18 A / D converter 19 Cable 20 Mounting member 30 Sub-scanning housing 31 Reading unit mounting portion 32 Bolt 33, 34 Conveyance roller pair (sub-scanning means) 35, 36, 37 Guide plate 40 Energy storage phosphor sheet 41 Light emission

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G083 AA03 BB04 CC10 DD11 DD16 EE10 2H013 AC04 AC05 5B047 AA17 AB02 BA01 BB02 BC05 BC12 BC14 BC18 BC20 5C072 AA01 BA02 CA06 DA02 EA05 VA01

Claims (5)

[Claims] 1. A light source for emitting excitation light for exciting a stimulable phosphor sheet on which radiation image information is stored and recorded, and the excitation light emitted from the light source is linearly converged on the stimulable phosphor sheet. An excitation light condensing lens to be provided, and a plurality of photoelectric conversion elements are juxtaposed along a linear excitation light irradiation portion of the stimulable phosphor sheet, and stimulated emission emitted from the excitation light irradiation portion is provided. A line sensor that detects light, one of the light source, the excitation light condensing lens and the line sensor, and the stimulable phosphor sheet intersect with the length direction of the excitation light irradiation part relative to the other. In a radiation image information reading apparatus comprising: a sub-scanning means for moving in a direction, the light source, the excitation light focusing lens and the line sensor are integrally fixed to a holding member while maintaining a predetermined relative positional relationship with each other, Member of retention, the stimulable phosphor sheet and the radiation image information reading apparatus, characterized in that mounted removably in the subscanning housing in relative movement related to the excitation light sub-scanning. 2. A stimulable luminescent light condensing lens which collects stimulable luminescent light emitted from a linear excitation light irradiated portion of the stimulable phosphor sheet and guides the stimulable luminescent light to the line sensor, 2. The radiation image information reading device according to claim 1, wherein the radiation image information reading device is fixed to the holding member while maintaining a predetermined relative positional relationship with the light focusing lens and the line sensor. 3. The radiation image information reading apparatus according to claim 1, wherein an amplifier for amplifying an output of the line sensor is fixed to the holding member. 4. The radiation image information reading apparatus according to claim 1, wherein an A / D converter for A / D converting an output of the line sensor is fixed to the holding member. . 5. A light source that emits excitation light for exciting a stimulable phosphor sheet on which radiation image information is stored and recorded, and the excitation light emitted from the light source is linearly converged on the stimulable phosphor sheet. An excitation light condensing lens, a line sensor in which a plurality of photoelectric conversion elements are juxtaposed along a linear excitation light irradiation portion of the stimulable phosphor sheet, the light source, the excitation light condensing lens, A radiation image information reading apparatus comprising: a line sensor; and a sub-scanning means for moving one of the stimulable phosphor sheets relative to the other in a direction intersecting the length direction of the excitation light irradiation portion. Wherein the light source and the excitation light collector are attached to a holding member that is detachably attached to a sub-scanning casing that is relatively moved with the stimulable phosphor sheet for excitation light sub-scanning. Lens and the line sensor, the reading unit formed by integrally fixed with a predetermined relative positional relationship with each other.