JP2002214727A - Apparatus and method for reading radiographic image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for reading a radiographic image which can quickly erase an after image on a stimulable phosphor after image reading is terminated in a reading part, and can shorten a cycle of radiation photographing, and to provide a method for the same. SOLUTION: The apparatus for reading a radiographic image detects maximum value data before transferring radiographic image information read from a stimulable phosphor panel 4 in a reading part 3 to a controller 18, and decides erasing light intensity with which the stimulable phosphor panel is irradiated for erasing the after image on the basis of the maximum value. Besides, data about an irradiation quantity may be acquired from an irradiation part in the reading part to decide the quantity of erasing on the basis of the acquired data. Or, the basic erasing of a fixed erasing quantity may be performed in the reading part to estimate the maximum value of the after image by the controller, and it may be determined whether or not the basic erasing is sufficient on the basis of the estimate, and a necessary quantity of erasing may be determined on the basis of the estimate to perform secondary erasing when it is inadequate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image reading apparatus and a radiation image reading method for reading radiation image information stored and recorded on a stimulable phosphor.

[0002]

2. Description of the Related Art Radiation images such as X-ray images are widely used for diagnosing diseases and the like.
The radiation transmitted through the subject is absorbed by the panel-like stimulable phosphor, and then the stimulable phosphor is excited while being scanned with, for example, a laser beam, so that the stimulable phosphor is accumulated by the absorption. A method is known in which radiation energy (radiation image information) is emitted as fluorescence, and this emission is photoelectrically converted to obtain a radiation image signal to read a radiation image (US Pat. No. 3,859,527 and Japanese Patent Application Laid-Open No. 55-12144, etc.). Since such a stimulable phosphor is repeatedly used, the afterimage is erased by light irradiation from a light irradiating unit such as a halogen lamp after reading is completed. In this case, even an afterimage of any large state can be erased. It is conceivable to irradiate an erasing light with a large energy erasing amount. However, in such a method, in most X-ray photography, the level of irradiation light for erasing is too high, so that the power consumption of the halogen lamp is increased or the life of the halogen lamp is shortened.

[0003] Therefore, the erasing amount is changed according to the residual energy level of the stimulable phosphor (Japanese Patent Laid-Open No. 61-2 / 1986).
Japanese Patent Application Laid-Open No. H06-175243) and a method of controlling the amount of erasure in accordance with a dynamic range (Japanese Patent Application Laid-Open No. H6-175243). In this case, the state of the afterimage can be inferred from the actually output image. Such a conventional method will be described with reference to FIG.

The radiation image reading apparatus is divided into a reading section and a controller. As shown in FIG. 10, data read by scanning the stimulable phosphor panel in the reading section is developed in a frame memory of the controller to form an image. Is obtained, the maximum value of the afterimage is estimated from the maximum value of the obtained image, and the irradiation amount (erasing amount) of the halogen lamp is determined based on the estimated value. As described above, the erasing amount is set from the maximum value of the image developed in the frame memory. One reading cycle is, for example, 16 seconds (11 seconds for reading, 5 for erasing).
Seconds). Further, in such a radiation image reading apparatus, the reading section and the controller are connected by a dedicated line for high-speed data transfer to transfer data.

However, in recent years, the above-mentioned dedicated line has been converted to a general-purpose line (for example, according to the IEEE standard) in order to improve the compatibility of the device. However, since the data transfer speed of such a general-purpose line is lower than that of the dedicated line, there is a case where the image cannot be developed in the frame memory by the controller even after the image is read by the reading unit. In this case, it is necessary to wait for erasure until the erasure amount is determined as described above, and there is a problem that the erasure of the afterimage is delayed and the cycle of radiation imaging is delayed.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of the prior art, and has been described in detail with reference to the drawings. It is an object of the present invention to provide a radiation image reading apparatus and a radiation image reading method capable of promptly deleting an afterimage on a stimulable phosphor and shortening a radiation imaging cycle.

[0007]

In order to achieve the above object, a first radiographic image reading apparatus according to the present invention provides a radiographic image reading apparatus which reads radiographic image information read from a stimulable phosphor by a reading unit to a controller. The maximum value data is detected, and the intensity of the erasing light applied to the stimulable phosphor is determined based on the maximum value data so as to eliminate the afterimage.

That is, a reading means for scanning a stimulable phosphor irradiated with radiation transmitted through a subject with excitation light to read radiation image information and outputting the radiation image information in a time-series manner; A reading unit including a light irradiation unit that irradiates the stimulable phosphor with erasing light to erase an afterimage of the phosphor, and a controller that stores and outputs radiation image information transmitted from the reading unit as image data. , The reading unit comprises: a maximum value holding unit that holds maximum value data of the image information before being transmitted to the controller; and a maximum value held by the maximum value holding unit. Erasing amount determining means for determining an erasing amount of the light irradiation means based on the value.

According to this radiation image reading apparatus, the erasing amount of the light irradiating means is determined by the reading unit based on the maximum value of the image information before being transmitted to the controller. There is no need to detect the maximum value and determine the amount of erasure based on the maximum value.The maximum value can be detected during data transfer to the controller, and the data is erased at the end of reading by the reading unit without waiting for the end of data transfer. The amount can be determined. Therefore, the elimination of the afterimage on the stimulable phosphor after the image reading by the reading unit is completed can be quickly executed,
The radiation imaging cycle can be shortened.

In a first radiographic image reading method according to the present invention, a stimulable phosphor irradiated with radiation transmitted through a subject is scanned with excitation light to read radiographic image information and output in time series. A reading unit that includes, after the reading, a light irradiating unit that irradiates the stimulable phosphor with erasing light to erase an afterimage of the stimulable phosphor, and a reading unit that is transmitted from the reading unit. A controller that expands the radiation image information, stores the image data as image data, and outputs the image data, wherein a maximum of the image information before being transmitted to the controller by the reading unit is provided. Value data is held, and the erasing amount of the light irradiation means is determined based on the held maximum value.

According to this radiation image reading method, similarly to the above, the maximum value can be detected during data transfer to the controller, and the amount of erasure is determined at the end of reading by the reading unit without waiting for the end of data transfer. it can. Therefore, the elimination of the residual image on the stimulable phosphor after the image reading by the reading section is completed can be quickly executed, and the cycle of radiation imaging can be shortened.

In this case, the image information is transmitted from the reading section to the controller via a general-purpose line, and even if the data transfer speed is low, the reading section does not wait for the completion of data transfer to the controller. Since the amount of erasure is determined at the end of reading and light irradiation for erasing afterimages can be performed, the cycle of radiation imaging does not become long.

Further, in the second radiation image reading apparatus according to the present invention, the reading section acquires data on the radiation dose from the radiation irradiating section, and irradiates the photostimulable phosphor to eliminate the afterimage based on the data. This is to determine the erasure amount.

A reading means for scanning the stimulable phosphor irradiated with the radiation radiated from the radiation irradiating section and transmitted through the object with excitation light to read radiation image information and outputting the radiation image information in time series; After reading, a reading unit including light irradiating means for irradiating the stimulable phosphor with erasing light in order to erase an afterimage of the stimulable phosphor, and radiation image information transmitted from the reading unit as image data. And a controller that stores and outputs the data as an erasing amount. The erasing amount determining unit determines an erasing amount of the light irradiating unit based on data related to radiation irradiation intensity from the radiation irradiating unit. Is provided.

According to this radiation image reading apparatus, the erasing amount is determined by the reading unit on the basis of the data on the irradiation amount of the radiation from the radiation irradiating unit. The erasure amount can be determined in stages. Therefore, the elimination of the residual image on the stimulable phosphor after the image reading by the reading section is completed can be quickly executed, and the cycle of radiation imaging can be shortened.

In this case, the data relating to the radiation irradiation intensity is the total irradiation amount and irradiation distance, the total irradiation amount of radiation in the reading unit, or at least the X-ray tube voltage, current, irradiation time, and irradiation distance. One can be included. In this case, the irradiation time is measured based on an irradiation signal from the radiation irradiation unit.

It is preferable that data on the radiation irradiation intensity is transmitted from the radiation irradiation unit to the reading unit in accordance with DICOM standards. Here, DICOM
Digital Imaging and COmmunications in Medi
An abbreviation for cine, a standard for "medical digital imaging and communication." This radiation image reading device uses a DIC
Current latest version of the OM standard PS3.3-19
It satisfies 99, but if it is further revised, it can be configured to cope with the revision.

In a second radiation image reading method according to the present invention, the radiation image information is read by scanning the stimulable phosphor irradiated with the radiation radiated from the radiation irradiator and transmitted through the subject with the excitation light. A reading unit that outputs in chronological order, and a reading unit that includes, after the reading, light irradiation means that irradiates the stimulable phosphor with erasing light to erase an afterimage of the stimulable phosphor, and A controller for storing and outputting the radiation image information transmitted from the reading unit as image data, the radiation image reading method in the radiation image reading apparatus comprising: The erasing amount of the light irradiation means is determined based on the data.

According to this radiation image reading method, the erasing amount is determined by the reading unit on the basis of the data on the irradiation amount of the radiation from the radiation irradiating unit. The erasure amount can be determined in stages. Therefore, the elimination of the residual image on the stimulable phosphor after the image reading by the reading section is completed can be quickly executed, and the cycle of radiation imaging can be shortened.

In this case, the data relating to the radiation irradiation intensity is the total irradiation amount and irradiation distance, the total amount of radiation incident on the reading unit, or at least the X-ray tube voltage, current, irradiation time, and irradiation distance. Can include one. In this case, the irradiation time is measured based on an irradiation signal from the radiation irradiation unit. In addition, data on the radiation irradiation intensity from the radiation irradiation unit is DI
Preferably, the data is transmitted to the reading unit in accordance with the COM standard.

Further, in the third radiation image reading apparatus according to the present invention, the reading section performs basic erasing with a fixed erasing amount, develops data from the reading section into the frame memory of the controller to obtain an image, and obtains the image. The maximum value of the afterimage is estimated from the maximum value of the image, and it is determined whether or not the basic erasure is sufficient based on the estimated value. Is what you do.

That is, a reading means for scanning a stimulable phosphor irradiated with radiation transmitted through a subject with excitation light to read radiation image information and outputting the radiation image information in a time-series manner; A reading unit including light irradiating means for irradiating the stimulable phosphor with erasing light in order to erase an afterimage of the phosphor, and a frame for expanding the radiation image information transmitted from the reading unit and storing the image as image data A controller that has a memory and outputs image data, in a radiation image reading apparatus that includes: a controller that obtains an image by expanding the image data in the frame memory;
A maximum erasing unit for estimating the maximum value of the afterimage from the maximum value of the obtained image, wherein the reading unit drives the light irradiation unit with a predetermined erasing amount to perform a basic erasing amount. Output means, determine whether the erasure by the basic erasure was sufficient based on the estimated value of the afterimage by the maximum value detection means, if insufficient, determine the required amount of erasure based on the estimated value Secondary erasing amount determining means for performing secondary erasing.

According to the radiation image reading apparatus, the reading section performs basic erasing with a fixed erasing amount, develops the data read by the reading section into the frame memory of the controller, obtains image data, and obtains the image data. Since the maximum value of the afterimage is estimated from the maximum value, it is determined whether the basic erasure is sufficient based on the estimated value, and if it is insufficient, the necessary erasure amount is determined based on the estimated value and the secondary erasure is performed. If the afterimage has disappeared in the basic erasure, the secondary erasure is not required, and the erasure of the afterimage can be executed quickly, and the cycle time of radiation imaging can be shortened.

In each of the above-described radiation image reading apparatuses, the image information is transmitted from the reading section to the controller via a general-purpose line, and even when the data transfer speed is low, the apparatus waits for the end of data transfer to the controller. In addition, afterimage erasure or basic erasure can be performed at the stage of completion of reading by the reading unit, so that the cycle of radiation imaging does not become long. Further, the above-mentioned erasing amount is determined by the product of the light amount and the irradiation time.

In a third radiographic image reading method according to the present invention, a stimulable phosphor irradiated with radiation transmitted through a subject is scanned with excitation light to read radiographic image information and output in time series. A reading unit including: reading means; and a light irradiating means for irradiating the stimulable phosphor with erasing light in order to erase an afterimage of the stimulable phosphor after the reading; and radiation transmitted from the reading unit. A controller for outputting image data, comprising: a frame memory for expanding image information and storing the image data as image data, and a controller for outputting image data. Driving and performing basic erasure; and developing the image data in the frame memory to obtain an image, and estimating the maximum value of the afterimage from the maximum value of the obtained image. Determining whether the erasure by the basic erasure is sufficient based on the estimated value of the afterimage, and determining the necessary erasure amount based on the estimated value if the basic erasure is insufficient. Performing secondary erasure by using

According to this radiation image reading method, the reading unit performs basic erasing with a fixed erasing amount, develops the data read by the reading unit into the frame memory of the controller, obtains an image, and obtains the maximum of the obtained image. Estimate the maximum value of the afterimage from the value, judge whether the basic erasure was sufficient based on the estimated value, and if insufficient, determine the necessary erasure amount based on the estimated value and perform secondary erasure, If the afterimage has disappeared by the basic erasure, it is not necessary to perform the secondary erasure, the erasure of the afterimage can be promptly executed, and the cycle time of radiation imaging can be shortened.

In each of the above-described radiation image reading methods, the image information is transmitted from the reading unit to the controller via a general-purpose line, and even if the data transfer speed is low, the controller waits for the end of data transfer to the controller. In addition, afterimage erasure or basic erasure can be performed at the stage of completion of reading by the reading unit, so that the cycle of radiation imaging does not become long. Further, the above-mentioned erasing amount is determined by the product of the light amount and the irradiation time.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, second and third embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>

FIG. 1 is a schematic diagram of a radiation image reading apparatus according to a first embodiment of the present invention, FIG. 2 is a block diagram showing a reading unit and a controller of FIG. 1, and FIG. FIG. 4 is a flowchart for explaining steps up to the elimination of an afterimage in the image reading apparatus, and FIG. 4 is a flowchart for explaining processing in the maximum value holding unit in FIG.

As shown in FIG. 1, the radiation image reading apparatus of the present embodiment irradiates an object irradiated from an X-ray irradiator 30 as an irradiator comprising an X-ray source 1 for irradiating X-rays and a controller 2. When the radiation transmitted through M is stored in the stimulable phosphor panel 4 as radiation image information, the stimulable phosphor panel 4 is scanned with excitation light to read the radiation image information and output in time series. And a light irradiating unit for irradiating the stimulable phosphor panel 4 with erasing light in order to erase an afterimage of the stimulable phosphor panel 4 after the reading.

The radiation image reading apparatus further includes a frame memory 19 for expanding the radiation image information transmitted from the reading section 3 and storing the developed image data as image data, and a controller 18 for outputting image data.

The reading means of the reading section 3 includes a stimulable phosphor panel 4, a laser light generating section 5 for generating laser light as excitation light for the stimulable phosphor panel 4, and a laser light generating section 5. , A reflector that reflects the laser light from the scanner 6 toward the stimulable phosphor panel 4, and a light emission from the stimulable phosphor panel 4 due to the laser light irradiation. , A current-to-voltage converter 11 for converting a current from the detector 20 to a voltage, a voltage amplifier 12 for amplifying the voltage, and a converter for converting the amplified voltage from analog to digital (A / D converter) 13.

The detector 20 includes a condenser 8 that collects fluorescence generated from the stimulable phosphor panel 4 when irradiated with laser light, a filter 9 that removes excess light, and a filter 9.
And a photomultiplier 10 for converting the light passing through to the electric signal.

The reading means of the reading unit 3 further includes a high-voltage power supply 16 for applying a voltage to the photomultiplier 10, a laser beam generating unit 5, a current-voltage converting unit 11, and a voltage amplifying unit 1.
2, a control unit 17 for controlling the A / D conversion unit 13 and the high-voltage power supply 16 respectively.

The light irradiating means for erasing the erasing light includes:
A halogen lamp 14 for irradiating the stimulable phosphor panel 4 with light while moving up and down in FIG.
And a driver 15 for driving the light irradiation and the movement.

The reading unit 3 and the controller 18
The signal is connected to a general-purpose interface (such as IEEE 1394 Ethernet (registered trademark)) or a dedicated line, and the signal of the radiation image information read by the reading unit 3 is transferred to the controller 18. IEEE is the Instit
It is a standard by the ute of Electrical and Electronics Engineers. Although the reading unit 3 and the controller 18 are housed in separate housings, they may be provided in the same housing and integrated to form a single device.

As shown in FIG. 2, the reading unit 3 further includes a maximum value holding unit 21 for holding the maximum value of the signal output from the voltage amplifying unit 12, and a maximum value held by the maximum value holding unit 21. An erasing amount determining unit 22 that determines an erasing amount (light quantity × irradiation time) of the light irradiation unit based on the value.

The maximum value holding unit 21 includes, for example, a storage unit 21a as a memory and a comparison unit 21b for comparing a stored value of the storage unit 21a with an input value, as shown in FIG. The comparison unit 21b can compare with the maximum voltage stored in the storage unit 21a, and if it is higher, store and hold the voltage as the maximum voltage in the storage unit 21a. The erasing amount determination unit 22 determines the erasing amount based on the maximum value. The erasing amount is determined by (light amount × irradiation time) of the halogen lamp 14, and in this example, the light amount is fixed and the irradiation time, that is, the irradiation time, The moving time of the halogen lamp 14 is changed. The driver 15 moves the halogen lamp 14 for the irradiation time (moving time) determined based on the erasure amount.

Further, as shown in FIG.
8 is provided with an image processing unit 25 for receiving a digital signal from the reading unit 3 and expanding the image data in the frame memory 19, and there is no means for determining the maximum value as in the related art.

Next, the operation of the radiation image reading apparatus shown in FIGS. 1 and 2 will be described with reference to FIG. First, when X-ray imaging is completed, it is determined whether or not the imaging is the last imaging (S0).
1) If it is not the last photographing, photographing is subsequently started (S
02), the X-ray source 1 irradiates the subject M with X-rays as shown in FIG. 1 (S3), and the stimulable phosphor panel 4 accumulates X-ray radiation image information.

Subsequently, when the laser beam is emitted from the laser beam generator 5 via the scanner 6 and the reflector 7 while irradiating the stimulable phosphor panel 4 (S04), the stimulable phosphor panel 4 is scanned. The light generated according to the accumulation level of the radiation image information is detected by the detector 20 and photoelectrically converted, thereby sequentially outputting image data (S05). The image data signal is converted into a digital signal via the current / voltage converter 11, the voltage amplifier 12, and the A / D converter 13, and then transmitted to the controller 18 via the general-purpose line 29 (S06).

Then, in the controller 18, the image data is expanded in the frame memory 19 by the image processing section 25 to which the digital signal is input (S07), and the image is output from the controller 18 (S08). Can be formed on a recording medium.

On the other hand, while the image data is sequentially output in step S05, the maximum value of the data is detected by the maximum value holding unit 21 based on the digital signal from the A / D conversion unit 13 (S09). When the scanning in step S04 and the sequential output of image data in step S05 are completed and the reading of the radiation image is completed, the maximum value is determined.
Is determined (S10), and by irradiating the stimulable phosphor panel 4 with light while moving the halogen lamp 14 during this movement time, the afterimage of the stimulable phosphor panel 4 for which reading has been completed is erased. (S11). This allows
When the process returns to step 02, it is possible to prepare for the next X-ray imaging.

As described above, the maximum value of the image data is detected by the maximum value holding unit 21 of the reading unit 3 separately from the image data being sequentially output by the reading unit 3 and sent to the controller 18, and the reading is performed. Simultaneously with the termination, the erasure amount is determined by the erasure amount determination unit 22, and the halogen lamp 14 is moved while the halogen lamp 14 is lit with this erasure amount, and the afterimage is erased. For this reason, the reading unit 3 can perform the next photographing without waiting for the image data transfer to the controller 18 and the development to the frame memory.

Therefore, it is not necessary to wait for the erasure until the amount of erasure is determined on the controller side as in the prior art, and the afterimage can be quickly erased, and the cycle of radiation imaging can be shortened. In particular, since the data transfer speed of the general-purpose line 29 is lower than that of the dedicated line, even if the reading unit finishes reading the image, the controller does not complete the expansion of the image to the frame memory and the shooting cycle becomes longer. In some cases, this problem is solved. Further, since the erasing amount (irradiation amount) of the stimulable phosphor panel 4 by the halogen lamp 14 is based on the maximum value of the data, the afterimage of the stimulable phosphor panel 4 is not hindered in the next photographing. Can be erased.

Next, referring to FIG. 4, the maximum value holding unit 2 shown in FIG.
1 will be described. The first read value is input to the maximum value holding unit 21 (S21), and while it is determined whether all readings from the stimulable phosphor panel 4 have been completed (S22), the first read value is set to the maximum value. The data is stored in the storage unit 21a of the holding unit 21 (S23). On the other hand, when the next read value is input to the comparing unit 21b, the stored value stored in the storage unit 21a is compared with the next read value (S25). Is stored in the storage unit 21a (S26). If the stored value is large, the stored value is stored again in the storage unit 21a (S27).

After step S26 or S27, while returning to step S22, the stored value is similarly successively compared with the next read value, and a larger value is newly stored in the storage unit 21a. When all readings are completed (S2
2) The last stored value stored in the storage unit 21a is output to the erasure amount determination unit 22 as the maximum value (S28).

In this example, the output value (read value) is set to A / D
Although the detection is performed before the A / D conversion in the conversion unit 13,
The detection may be performed after the AD conversion.

<Second Embodiment>

FIG. 5 is a block diagram showing a reading unit and a controller in a radiographic image reading apparatus according to a second embodiment of the present invention. FIG. 6 shows steps in the radiographic image reading apparatus of FIG. It is a flowchart for explaining.

In the radiation image reading apparatus of the present embodiment, the erasing amount determining section of the reading section is different from that of FIGS.
Since the configuration is almost the same except that the amount of erasure is determined based on the data on the radiation irradiation intensity from, the same parts are denoted by the same reference numerals and description thereof will be omitted.

As shown in FIG. 5, the X-ray irradiation unit 30
A tube voltage output unit 31, a current output unit 32, and an irradiation time output unit 3 that respectively output a tube voltage, a current, an irradiation time, and an irradiation distance when the X-ray source 1 generates X-rays toward a subject.
3 and an irradiation distance output unit 34, and further calculates an irradiation amount of the irradiated X-ray from each output value of each of the output units 31 to 34, and outputs an X-ray irradiation amount output unit 35 which outputs the irradiation amount together with the irradiation distance.
Is provided.

As shown in FIG. 5, the X-ray
X-ray irradiation output unit 35 and device control unit 2 of controller 18
9, data communication is performed according to the DICOM standard via the Ethernet 39. For example, X
The X-ray irradiation intensity information is sent from the X-ray irradiation output unit 35 to the device control unit 29.

The reading section 3 includes an X-ray interface (IF) section 28 connected to the X-ray control section 2 of the X-ray irradiating section 30, and the X-ray control section 2 and the X-ray interface (I
F) Signals are exchanged with the unit 28. The X-ray IF unit 28 and the erasing amount determination unit 22 of the reading unit 3 in FIG. 5 are connected to the device control unit 29 of the controller 18. Thereby, for example, the irradiation signal output from the X-ray control unit 2 during X-ray irradiation by the X-ray
The X-ray irradiation time can be measured from the irradiation signal sent to the device control unit 29 via the F unit 28.

The erasing amount determining unit 22 of the reading unit 3 shown in FIG.
Determines the erasing amount (irradiation time in this example) of the halogen lamp 14 based on the total X-ray irradiation amount and the irradiation distance sent from the X-ray irradiation amount output unit 35 to the device control unit 29 via the Ethernet 39. It has become.

Next, the operation of the radiation image reading apparatus of FIG. 5 will be described with reference to FIG. Steps S01 to S08 in FIG. 6 are the same as those in FIG. 3, and a description thereof will be omitted. When X-rays are emitted from the X-ray irradiator 30 in step S03, the X-ray irradiance output unit 35 of the X-ray irradiator 30 sends the total X-ray irradiation amount and irradiation distance in step S03 to the controller 18 via the Ethernet 39. Device control unit 29
To the reading unit 3 from the device control unit 29 (S31). The erasure amount is determined by the erasure amount determination unit 22 of the reading unit 3 from the notified irradiation total amount and the irradiation distance (S3).
2). Specifically, in this example, the erasing amount determination unit 22 determines the moving time (irradiation time) of the halogen lamp 14 as a constant light amount based on the total irradiation amount and the irradiation distance, and moves the halogen lamp 14 during this moving time. By irradiating the stimulable phosphor panel 4 with light, the afterimage of the stimulable phosphor panel 4 that has been read is erased (S33). Thereby, when returning to step 02, it is possible to prepare for the next X-ray imaging.

As described above, when X-rays are emitted from the X-ray irradiator 30, the erasure amount determiner 22 of the reading unit 3 determines the amount of irradiation and the irradiation distance notified from the X-ray irradiator 30. The amount of erasure can be determined, and immediately after the reading by the reading unit 3 is completed, the halogen lamp 14 moves with the determined erasure amount while being turned on, and the afterimage is erased. For this reason, the reading unit 3 can perform the next photographing without waiting for the image data transfer to the controller 18 and the development to the frame memory.

Therefore, it is not necessary to wait for the erasure until the amount of erasure is determined by the controller as in the prior art, and the afterimage can be quickly erased, and the cycle of radiation imaging can be shortened. In particular, when a general-purpose line is used, the data transfer speed is lower than that of a dedicated line. Is sometimes longer, but this problem is solved. Also,
Since the erasing amount (irradiation amount) of the stimulable phosphor panel 4 by the halogen lamp 14 is based on the total irradiation amount and the irradiation distance of the X-rays, the after-image of the stimulable phosphor panel 4 interferes with the next photographing. Can be erased without the occurrence of

In the present embodiment, the X-ray irradiation unit 30 outputs the total amount of X-ray irradiation and the irradiation distance. However, the stimulable phosphor of the reading unit 3 obtained from the total irradiation amount and irradiation distance is used. The total amount of light incident on the panel 4 may be used.

When one or more of the values of the X-ray tube voltage, current, irradiation time, and irradiation distance are known on the reading unit 3 side, another reading unit 3 can estimate the total incident amount. X-ray tube voltage, current, irradiation time, and irradiation distance data can be output. The X-ray irradiation time is determined by the X-ray controller 2
It can be obtained by measuring the time during which the X-ray irradiation signal is output from the device controller 29 of the controller 18.

<Third Embodiment>

FIG. 7 is a block diagram showing a reading unit and a controller in a radiation image reading apparatus according to a third embodiment of the present invention. FIG. 8 shows basic erasure and secondary erasure in the radiation image reading apparatus of FIG. 9 is a diagram for explaining the effect of shortening the imaging cycle in the radiation image reading apparatus of FIG.

In the radiation image reading apparatus of this embodiment, as compared with FIGS. 1 and 2, a controller is provided with a maximum value detecting section, and a controller is provided based on the basic erasure amount output section and the maximum value from the maximum value detecting section. The configuration is almost the same except that the reading unit is provided with a secondary erasing amount determining unit for determining the next erasing amount. Therefore, the same parts are denoted by the same reference numerals and the description thereof is omitted.

As shown in FIG. 7, the controller 18 has a maximum value for estimating the maximum value of the afterimage from the maximum value detected from the image data obtained by expanding the image data in the frame memory 19 by the image processing unit 25. A detection unit 41 is provided.

The reading unit 3 includes a basic erasure amount output unit 42 for driving the halogen lamp 14 to perform a basic erasure at a predetermined erasure amount capable of sufficiently erasing the accumulated afterimage during, for example, chest imaging, and a controller. 18 maximum value detector 41
Judge whether the basic erasure is sufficient based on the maximum value of the afterimage estimated by the above, and if it is insufficient, determine the necessary erasure amount based on the estimated maximum value and perform secondary erasure An erasing amount determining unit 43 is provided. In this example,
The erasing amounts of the basic erasing and the secondary erasing are controlled so that the irradiation time (moving time) is changed while the light amount is constant.

Next, the operation of the radiation image reading apparatus of FIG. 7 will be described with reference to FIG. Steps S01 to S08 in FIG. 8 are the same as those in FIG. 3, and a description thereof will be omitted. When the image reading by the scanning in step S04 is completed, the driver 15 drives the halogen lamp 14 while moving the halogen lamp 14 by the output from the basic erasure amount output unit 42 for the predetermined erasure time to perform the basic erasure (S4).
1). In parallel with the basic erasure, the data read by the reading unit 3 is expanded in the frame memory 19 of the controller 18 to obtain an image, and the maximum value detection unit 41 estimates the maximum value of the afterimage from the maximum value of the obtained image. (S42). Then, the secondary erasure amount determination unit 43 of the reading unit 3 determines whether or not the erasure is sufficient in the basic erasure based on the maximum value of the afterimage of the maximum value detection unit 41 (S43).
Return to and perform the next shooting.

For example, if the photographing is performed on the lower back and the erasure of the afterimage by the basic erasure in step S41 is insufficient, the secondary erasure amount determination unit 43 determines the necessary erasure amount based on the maximum value of the afterimage. Then, secondary erasing is performed by the halogen lamp 14 using the erased amount (S45). As a result, even if the afterimage is not sufficiently erased by the basic erase, the afterimage can be surely erased by the secondary erase. If the afterimage has disappeared by the basic erasure, the secondary erasure is not necessary, and the erasure of the afterimage can be executed quickly, and the cycle time of radiation imaging can be shortened.

The effect of this embodiment will be further described with reference to FIG. As shown in FIG. 9, when the secondary erasure does not need to be performed (2), the basic erasure is performed immediately after the reading is completed, and the basic erasure is performed while the image data is transferred from the reading unit to the controller. Since the processing is completed, the time ΔT required for erasure performed after the image data is transferred as in the conventional example (1).
Only the shooting cycle can be shortened.

Even in the case of performing the secondary erasing (3), the basic erasing is completed during the transfer of the image data, and the same time as that of the conventional erasing is used, so that the photographing cycle does not become long.

As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made within the technical idea of the present invention. For example, although the irradiation time is changed while the light amount is constant, the light amount may be changed while the irradiation time is constant, or both may be changed.

[0072]

According to the present invention, there is provided a radiation image reading apparatus and a radiation image reading apparatus capable of promptly erasing an afterimage of a stimulable phosphor after completion of image reading by a reading section and shortening a radiation imaging cycle. A radiation image reading method can be provided.

Further, even when the image information is transmitted from the reading unit to the controller via the general-purpose line and the data transfer speed is low, the afterimage is deleted at the stage when the reading is completed by the reading unit without waiting for the completion of the data transfer to the controller. Alternatively, since the basic erasure can be performed, the cycle of radiation imaging does not become long.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a radiation image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a reading unit and a controller of FIG. 1;

FIG. 3 is a flowchart for explaining steps up to the elimination of an afterimage in the radiation image reading apparatus of FIG. 1;

FIG. 4 is a flowchart for explaining processing in a maximum value holding unit in FIG. 2;

FIG. 5 is a block diagram illustrating a reading unit and a controller in a radiation image reading apparatus according to a second embodiment of the present invention.

FIG. 6 is a flowchart for explaining steps up to the elimination of an afterimage in the radiation image reading apparatus of FIG. 5;

FIG. 7 is a block diagram illustrating a reading unit and a controller in a radiation image reading apparatus according to a third embodiment of the present invention.

FIG. 8 is a flowchart for explaining steps up to basic erasure and secondary erasure in the radiation image reading apparatus of FIG. 7;

FIG. 9 is a diagram for explaining an effect of shortening an imaging cycle in the radiation image reading apparatus of FIG. 7;

FIG. 10 is a flowchart illustrating steps up to erasure of an afterimage in a conventional radiation image reading apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 X-ray source 3 Reading part 4 Stimulable phosphor panel (Stimulable phosphor) 5 Laser light generation part 13 A / D conversion part 14 Halogen lamp (Light irradiation means) 18 Controller 19 Frame memory 20 Detector 21 Maximum value Holding unit 22 Erase amount determination unit 25 Image processing unit 30 X-ray irradiation unit 35 X-ray irradiation amount output unit 39 Ethernet 41 Maximum value detection unit 42 Basic irradiation amount output unit 43 Secondary erase amount determination unit

Claims (18)

[Claims] 1. A reading means for scanning a stimulable phosphor irradiated with radiation transmitted through a subject with excitation light to read radiation image information and outputting the radiation image information in a time series, and after the reading, the stimulable phosphor A reading unit including light irradiation means for irradiating the stimulable phosphor with erasing light to delete an afterimage of the phosphor, a controller storing and outputting radiation image information transmitted from the reading unit as image data, In the radiation image reading apparatus comprising: the reading unit, a maximum value holding unit that holds the maximum value data of the image information before being transmitted to the controller,
A radiation image reading apparatus comprising: an erasing amount determining unit that determines an erasing amount of the light irradiation unit based on a maximum value held by the maximum value holding unit. 2. A reading means for scanning a stimulable phosphor irradiated with radiation transmitted through a subject with excitation light to read radiation image information and outputting the radiation image information in a time-series manner; A reading unit including a light irradiating unit that irradiates the stimulable phosphor with erasing light in order to delete an afterimage of the phosphor; and a controller that stores and outputs the radiation image information transmitted from the reading unit as image data. A radiation image reading method in a radiation image reading apparatus, comprising: holding a maximum value data of the image information before being transmitted to the controller in the reading unit, based on the held maximum value A radiation image reading method for determining an erasing amount of the light irradiating means. 3. A reading means for scanning a stimulable phosphor irradiated with radiation transmitted from a radiation irradiator and transmitted through a subject with excitation light to read radiation image information and outputting the radiation image information in a time-series manner, After reading, a reading unit including light irradiating means for irradiating the stimulable phosphor with erasing light in order to erase an afterimage of the stimulable phosphor, and radiation image information transmitted from the reading unit as image data. A radiation image reading apparatus comprising: a controller that stores and outputs the data as: a reading amount determining unit that determines an erasing amount of the light irradiation unit based on data on a radiation irradiation intensity from the radiation irradiation unit. A radiation image reading apparatus comprising: 4. The data relating to the radiation irradiation intensity,
The radiation image reading device according to claim 3, wherein the radiation image reading device is an irradiation total amount and an irradiation distance. 5. The data related to the radiation irradiation intensity,
The radiation image reading apparatus according to claim 3, wherein the radiation image reading apparatus is a total amount of radiation incident on the reading unit. 6. The data related to the radiation irradiation intensity,
The radiation image reading device according to claim 3, wherein the radiation image reading device includes at least one of an X-ray tube voltage, a current, an irradiation time, and an irradiation distance. 7. The radiation image reading apparatus according to claim 6, wherein the irradiation time is measured based on an irradiation signal from the radiation irradiation unit. 8. A reading means for scanning a stimulable phosphor irradiated with radiation transmitted from a radiation irradiator and passing through a subject with excitation light to read radiation image information and outputting the radiation image information in a time-series manner, After reading, a reading unit including light irradiating means for irradiating the stimulable phosphor with erasing light in order to erase an afterimage of the stimulable phosphor, and radiation image information transmitted from the reading unit as image data. A radiation image reading apparatus, comprising: a controller that stores and outputs the radiation amount as the irradiating amount of the light irradiating means based on data on the radiation irradiation intensity from the radiation irradiating unit in the reading unit. The radiation image reading method to be determined. 9. The data related to the radiation irradiation intensity,
The radiation image reading method according to claim 8, wherein the radiation image reading amount and the irradiation distance are used. 10. The radiation image reading method according to claim 8, wherein the data on the radiation irradiation intensity is a total amount of radiation incident on the reading unit. 11. The radiation image reading method according to claim 8, wherein the data relating to the radiation irradiation intensity includes at least one of an X-ray tube voltage, a current, an irradiation time, and an irradiation distance. 12. The radiation image reading method according to claim 11, wherein the irradiation time is measured based on an irradiation signal from the radiation irradiation unit. 13. A reading means for scanning a stimulable phosphor irradiated with radiation transmitted through a subject with excitation light to read radiation image information and outputting the radiation image information in a time-series manner; A reading unit including light irradiating means for irradiating the stimulable phosphor with erasing light to erase an afterimage of the phosphor, and a frame for expanding the radiation image information transmitted from the reading unit and storing it as image data A controller having a memory and outputting image data, wherein the controller expands the image data in the frame memory to obtain an image, and obtains an afterimage from a maximum value of the obtained image. A maximum value detection unit for estimating a maximum value of, the reading unit includes: a basic erasure amount output unit that drives the light irradiation unit with a predetermined erasure amount to perform a basic erasure; It is determined whether or not the erasure by the basic erasure has been sufficient based on the estimated value of the afterimage by the maximum value detection means, and if it is not sufficient, the necessary amount of erasure is determined based on the estimated value to perform secondary erasure. A radiation image reading apparatus comprising: 14. The apparatus according to claim 1, wherein said image information is transmitted from said reading unit to said controller via a general-purpose line.
14. The radiation image reading device according to any one of claims 7 to 13. 15. The radiation image reading apparatus according to claim 1, wherein the erasing amount is determined by a product of a light amount and an irradiation time. 16. A reading means for scanning a stimulable phosphor irradiated with radiation transmitted through a subject with excitation light to read radiation image information and outputting the radiation image information in a time-series manner, and after the reading, the stimulable phosphor has A reading unit including light irradiating means for irradiating the stimulable phosphor with erasing light to erase an afterimage of the phosphor, and a frame for expanding the radiation image information transmitted from the reading unit and storing it as image data A radiation image reading method in a radiation image reading apparatus, comprising: a controller having a memory and outputting image data, wherein a basic erasing is performed by driving the light irradiating means with a predetermined erasing amount; Developing an image in the frame memory to obtain an image, estimating a maximum value of the afterimage from a maximum value of the obtained image, and Determining whether the erasure by the main erasure is sufficient, and performing a secondary erasure by determining a necessary erasure amount based on the estimated value if the basic erasure is insufficient. Reading method. 17. The controller according to claim 2, wherein the image information is transmitted from the reading unit to the controller via a general-purpose line.
The radiographic image reading method according to any one of claims 12 to 16. 18. The radiation image reading method according to claim 2, wherein the erasing amount is determined by a product of a light amount and an irradiation time.