JP2001074897A - Radiation pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily avoid the degradation of picture quality due to the unevenness of the intensity of a sensor detection signal. SOLUTION: In this X-ray pickup device, an X-ray detection element corresponding to the same image pickup point of a specimen M is continuously shifted by inching an X-ray sensor 2 shaped like a panel with X and Y inching sections 4 and 5. Meanwhile, the X-ray camera device includes a structure where a displacement between images associated with the small movement of the X-ray sensor 2 shaped like a panel is inhibited according to the position correspondence relation between the sensor 2 and the specimen M detected by a position correspondence relation detecting section 18. As a result, five different X-ray detection elements are used evenly for each image pickup point of the specimen M, and the unevenness of detection properties on the detection surface is mitigated to lower the influence of the fluctuation. Consequently, the degradation of picture quality of X-ray images due to the unevenness of the intensity of a detection signal can be avoided easily without causing the image slippage between images and degrading a space resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation imaging apparatus provided with a solid-state radiation detector for detecting transmitted radiation and used in the medical field, the industrial field, or the nuclear field, and more particularly to an output from the solid-state radiation detector. The present invention relates to a technique for easily resolving deterioration in image quality of a radiation image caused by (local) intensity unevenness of a detection signal.

[0002]

2. Description of the Related Art Recently, as an X-ray imaging apparatus used in the medical and industrial fields, as shown in FIG. 14, an X-ray tube 51 for irradiating an object M with X-rays and a flat panel for detecting transmitted X-rays are shown. And a flat panel X-ray sensor 52 (solid-state two-dimensional X-ray detector) 52 that is opposed to the subject M placed on the top plate 53. In the control system at the subsequent stage, signal processing is performed based on the (X-ray) detection signal output from the flat panel X-ray sensor 52 in accordance with the X-ray irradiation on the subject M, and the X- There are devices configured to obtain line images.

A flat panel X-ray sensor 52 is shown in FIG.
As shown in FIG. 5, an X-ray detecting element 52 having an X-ray sensitive film
a is a two-dimensional X-ray detector which is arranged in a large number in the form of an XY matrix on the detection surface, and is a very lightweight, thin, and large-area X-ray detector.
By using the structure, the structure of the X-ray imaging apparatus can be improved.

[0004]

However, the conventional flat panel type X-ray sensor 52 has unevenness in detection signal intensity. In other words, differences in detection sensitivity and offset between the X-ray detection elements 52a, and differences in the amplification factors of the preamplifiers that amplify the output current of the X-ray detection elements 52a cause differences in the intensity of the detection signal. There is unevenness. The unevenness in the intensity of the detection signal appears as spots or slightly vertical stripes or horizontal stripes on the X-ray image, deteriorating the image quality.

In a conventional X-ray imaging apparatus, correction data for suppressing signal intensity unevenness of the flat panel type X-ray sensor 52 is measured and stored in advance for each X-ray detection element 52a, and actual X-ray imaging is performed. Flat panel type X obtained in case of
Although the configuration is such that the intensity of the detection signal output from the line sensor 52 is corrected in accordance with the correction data, since the signal intensity unevenness of the detection signal itself fluctuates with time, the correction data is frequently measured. It is not easy to eliminate the deterioration of the image quality due to the uneven signal intensity of the detection signal of the flat panel X-ray sensor 52.

On the other hand, a small area flat panel type X-ray sensor (mini X-ray sensor) having a small signal intensity non-uniformity is integrated by a tile-attached type to have a large area.
There are also line sensors. In this sensor, although the signal intensity unevenness in each mini X-ray sensor is reduced to some extent, there is a difference in the signal intensity between the mini X-ray sensors and the mini X-ray sensor has a difference.
A large level difference in signal strength tends to occur at a position corresponding to the joint of the line sensor, and appears as a vertical stripe or a horizontal stripe in an image.

The present invention has been made in view of the above circumstances, and provides a radiation imaging apparatus capable of easily resolving deterioration in the quality of a radiation image caused by unevenness in the intensity of a detection signal output from a solid-state radiation detector. As an issue.

[0008]

According to a first aspect of the present invention, there is provided a radiation imaging apparatus for irradiating a subject with radiation, and a radiation detecting element having a radiation sensitive film. A plurality of solid-state radiation detectors for detecting transmitted radiation arranged on a detection surface, and signal processing for obtaining a radiation image of the subject based on a detection signal output from the radiation detector upon irradiation of the subject with radiation. Position change which continuously executes a position change between the radiation detector and the subject in a direction parallel to the detection surface of the radiation detector (detection surface direction). Execution means, and a position correspondence detection means for detecting, at every moment, a position correspondence relation between the detection surface of the radiation detector and the object in the detection surface direction, and the signal processing means includes: Based on the positional correspondence detected by the response detecting means, an image shift prevention process for preventing an image shift from occurring between images due to a change in the position of the detection surface of the radiation detector and the subject in the detection surface direction is performed. It is configured.

According to a second aspect of the present invention, in the radiation imaging apparatus according to the first aspect, the signal processing means also performs an image synthesizing process for synthesizing a plurality of radiation images obtained before and after in time. It is configured.

[Operation] Next, the operation of each radiation imaging apparatus according to the present invention will be described. When a radiation image is obtained by the radiation imaging apparatus according to claim 1, a detection signal is output from the solid-state radiation detector in accordance with the irradiation of the radiation to the subject by the radiation irradiation unit, and the detection signal of the radiation is output by the signal processing unit. Based on the signal processing, a radiation image of the subject is obtained.

On the other hand, in the radiation imaging apparatus according to the first aspect, the position change execution means continuously changes the position of the radiation detector in the detection surface direction. Since the radiation detecting element corresponding to the same imaging point of the subject changes every moment with the change of the position of the radiation detector in the detection plane direction, if it is left as it is, the imaging position shifts and between images which are temporally back and forth. An image shift occurs and the image quality deteriorates. On the other hand, in the radiation imaging apparatus according to the first aspect, the position correspondence relation between the detection surface of the radiation detector and the subject in the direction of the detection surface is detected by the position correspondence detection unit every moment. Since the positional correspondence between the detection surface of the radiation detector and the subject in the detection surface direction corresponds to the imaging position, the position detected by the position correspondence detection unit at the time of signal processing by the signal processing unit is momentarily detected. Since the image shift preventing process performed in accordance with the correspondence relationship does not cause a shift in the photographing position, the image shift between images that are temporally adjacent to each other is prevented.

In the radiation imaging apparatus according to the first aspect,
The radiation detecting element corresponding to the same imaging point of the subject is not constant, and is constantly changing between the radiation detecting elements having different detection signal intensities, and a plurality of (different) radiation detections are performed at the same imaging point of the subject. Since the elements are used on average, the unevenness of the detection characteristics of the detection surface is reduced and the effect of the fluctuation is suppressed, so that the deterioration of the quality of the radiation image due to the unevenness of the intensity of the detection signal can be easily eliminated. Becomes Note that the averaging for reducing the intensity unevenness of the detection signal is not the averaging for a plurality of imaging points of the subject, but the averaging for the same imaging point of the subject.
The averaging of a plurality of imaging points of the subject does not cause a decrease in spatial resolution (blur of an image) that occurs.

In the case of the radiation imaging apparatus according to the second aspect, in the signal processing by the signal processing means, a plurality of radiation images obtained before and after in time by image combining processing are combined. In the image obtained by this image synthesis processing, since each pixel signal is obtained by averaging detection signals of different radiation detection elements for the same imaging point of the subject, the intensity unevenness of the detection signal over the entire image is sufficient. This results in a high-quality radiation image that has been alleviated.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows X according to the first embodiment.
FIG. 2 is a block diagram showing the overall configuration of the line imaging apparatus, and FIG. 2 is a schematic front view showing the configuration of the imaging system of the first embodiment. First
As shown in FIGS. 1 and 2, the X-ray imaging apparatus according to the embodiment includes an X-ray tube 1 that irradiates the subject M with X-rays, and a flat panel X-ray sensor (solid-state type 2) for detecting transmitted X-rays. (A two-dimensional X-ray detector) 2 is opposed to the subject M placed on the top 3 with a subject M on the control system side at the subsequent stage of the flat panel X-ray sensor 2. The signal processing is performed based on the detection signal output from the flat panel X-ray sensor 2 with the X-ray irradiation on the sample M, and an X-ray image of the subject M is obtained. Hereinafter, the configuration of each part of the first embodiment will be specifically described.

The X-ray imaging apparatus according to the first embodiment has, as one of characteristic features, a panel type X-ray
An X fine movement unit 4 and a Y fine movement unit 5 are provided between the line sensor 2 and the subject M for fine movement in a direction parallel to the detection surface of the panel type X-ray sensor 2 (detection surface direction). These X fine movement parts 4
The Y fine movement unit 5 moves the panel X-ray sensor 2 in the direction of the detection surface by the arrow R under the control of the position change control unit 6.
It is configured to reciprocate periodically in the directions indicated by A and RB. That is, the X fine movement unit 4 and the Y fine movement unit 5 and the position change control unit 6 continuously change the position of the panel X-ray sensor 2 in the direction of the detection surface between the panel X-ray sensor 2 and the subject M. This constitutes the position change executing means caused by the above. As the X fine movement unit 4 and the Y fine movement unit 5, for example, a minute movement mechanism using an electrostrictive element that generates a mechanical displacement upon receiving an electric signal, a screw feed mechanism driven by a pulse motor, or the like is used.

With respect to the X-ray tube 1, the X-ray tube 1 emits X-rays according to set irradiation conditions such as a tube voltage and a tube current under the control of an irradiation control unit 7 including a high voltage generator and the like.
Is configured to be irradiated. Panel type X-ray sensor 2
As shown in FIG. 3, many X-ray detecting elements 2
a is an XY matrix (1024 × 1024) on the detection surface
After the charge signals accumulated in the respective X-ray detection elements 2a are sequentially read out with the X-ray irradiation under the control of the readout control unit 8, the charge signals are amplified and A / D-converted ( (X-ray) detection signal is output to the control system side. With respect to the top 3, X (horizontal) with the subject M mounted is controlled by the control of the top driving unit 9.
• Top plate 3 only for the required distance in each of the Y (vertical) and Z (vertical) directions
Is configured to move. The control by the position change control unit 6, the irradiation control unit 7, the readout control unit 8, and the top plate driving unit 9 is performed by the photographing control unit 10 according to the input operation from the console 11 or the photographing progress timely. Is performed in accordance with a command signal sent to the

On the other hand, the X-ray imaging apparatus according to the first embodiment has a detection signal memory (original image memory) 12 for storing a detection signal output from the panel type X-ray sensor 2, and necessary signal processing based on the detection signal. And an X-ray image memory 14 for storing an X-ray image obtained by executing the signal processing, and variations in offsets and sensitivities (gains) of respective elements of the panel type X-ray sensor 2. In addition to the correction data memory 15 for correcting the X-ray image, a display monitor 16 for displaying the X-ray image stored in the X-ray image memory 14 and the X-ray image stored in the X-ray image memory 14 are printed on the film. An image printer (laser imager) 17 for outputting as an image photograph is also provided. Further, as will be described in detail later, the X-ray imaging apparatus according to the first embodiment has a positional correspondence relationship for detecting the positional correspondence between the detection surface of the panel X-ray sensor 2 and the subject M in the detection surface direction every moment. A detecting unit (position correspondence detecting unit) 18 is provided as another characteristic configuration. Also, the signal processing unit 13
Can be used as necessary signal processing, such as edge enhancement, filtering, or digital subtraction (DS).
In addition to performing A) and the like, an image shift prevention process for preventing an image shift occurring between images obtained before and after in time is also performed based on the detection result of the positional correspondence detection unit 18 as described later in detail. It is configured as follows.

The correction data stored in the correction data memory 15 is as follows. According to the intensity of the detection signal when the X-ray is not irradiated and the intensity of the detection signal obtained by irradiating the X-ray without the subject, data is obtained for the offset and the sensitivity for each of all the X-ray detection elements 2a, and in the form of a correction table. It is memorized. In this embodiment, the reason why the correction data memory 15 is provided is that it is assumed that there is an extreme variation in X-ray intensity that cannot be completely corrected by the slight movement of the panel X-ray sensor 2.

Next, the configurations of the position change executing means and the position correspondence detecting means, which are characteristic structures of the present invention, will be described in detail. The position change executing means of the first embodiment device includes:
Between the panel-type X-ray sensor 2 and the subject M, in parallel with the detection surface of the panel-type X-ray sensor 2 and in an oblique direction at an angle of 45 ° to the right with respect to the XY matrix arrangement (a distance of about 1 mm)
Is continuously executed. FIG.
As shown in the figure, at the reference position of the panel type X-ray sensor 2,
The (i, i) -th X-ray detection element 2a corresponds to the imaging point Ma of the subject M. First, X fine movement section 4 and Y
The fine movement unit 5 is controlled by the position change control unit 6
The panel type X-ray sensor 2 is horizontally moved forward (right = +) by one X-ray detecting element in the X direction, and at the same time, the X direction is
It is moved horizontally (upward =-) by one line detection element. Then, as shown in FIG. 5, (i)
The (−1, i + 1) th X-ray detection element 2a corresponds to the (−1, i + 1) th X-ray detection element 2a. Subsequently, in the same manner, the X direction is further horizontally moved forward (right) by one X-ray detecting element, and the Y direction is further shifted by X.
When it is moved horizontally (upward) by one line detection element,
The illustration is omitted at the photographing point Ma (i-2, i + 2).
The second X-ray detection element 2a corresponds to this.

Next, contrary to the above, the X direction is horizontally moved backward (left =-) by one X-ray detecting element, and the Y direction is moved forward (lower) by one X-ray detecting element. = +). Then, the X-ray detecting element 2a corresponding to the imaging point Ma is the (i-1, i + 1) -th order shown in FIG. 5, the (i, i) -th order shown in FIG. 4, and the (i + 1, i) -th order shown in FIG.
The illustration is further omitted from the (i-1) -th (i +)
After changing to the (2, i−2) th element, it is inverted again and changes to the (i−2, i + 2) th element in order.

That is, as described above, the position change executing means of the apparatus of the first embodiment performs the (i-2, i + 2) -th, (i-
(1, i + 1) th, (i, i) th, (i + 1, i-
By repeating reciprocating movement between the 1) th and (i + 2, i-2) th five X-ray detection elements 2a, the position of the panel X-ray sensor 2 in the direction of the detection surface is changed. Of course, for the other imaging points of the subject M, 5
The position changes among the X-ray detection elements 2a are performed simultaneously and in parallel. Usually, the sampling period of the detection signal (and the change period of the X-ray detection element are synchronized, and after the detection signal for one image is collected, the configuration is switched to the next X-ray detection signal.

On the other hand, in the first embodiment, the address of the detection signal memory 12 shown on the right side of FIG.
When the panel-type X-ray sensor 2 is in the reference state shown in FIG. 4, the address (address) of the panel-type X-ray sensor 2 shown on the left side of FIG. Is coincident with the address of the detection signal memory 12 shown in FIG. However, when the panel-type X-ray sensor 2 is moved from the reference state with respect to the detection surface direction, the panel-type X-ray sensor 2
Does not match the address of the detection signal memory 12. FIG.
As shown in FIG. 8, when the panel-type X-ray sensor 2 is moved diagonally upward to the right, as shown in FIG.
The panel type X-ray sensor 2 shifts obliquely downward to the left with respect to address 2. As shown in FIG. 6, when the panel-type X-ray sensor 2 is moved diagonally downward to the left, as shown in FIG. Shift up. Therefore, if an X-ray image is obtained by directly performing signal processing on an original image obtained over time, an image shift occurs between images obtained before and after in time according to a sample period. The displacement causes a decrease in spatial resolution (image blur).

On the other hand, based on the control signal of the position change control section 6, the position correspondence detecting section 18 of the apparatus of the first embodiment detects the position of the panel-type X-ray sensor 2 and the object M in the direction of the detecting plane. The correspondence is detected every moment. That is, the positional correspondence detection unit 18 determines the amount of movement (any of 0, 1 element, or 2 elements) and the direction [+ direction from the reference position of the panel X-ray sensor 2 in each of the X and Y directions. ,-Direction) and sends it to the signal processing unit 13 as position correspondence data.

The signal processor 13 corrects the offset / sensitivity of the detection signal in accordance with the data stored in the correction data memory 15, and converts the image signal obtained by performing other necessary signal processing such as filtering. The X-ray image is completed by storing it in the X-ray image memory 14. When storing the image signal in the X-ray image memory 14, address correction processing is performed according to the positional correspondence data.
That is, since the address of the detection signal memory 12 and the address of the X-ray image memory 14 correspond one to one, for example,
In the case where there is a shift shown in FIG. 8, the storage address in the X direction is advanced by one or two addresses ahead of the read address by one or two in accordance with the moving distance of the positional correspondence data (1 element or 2 elements). The storage address in the direction is delayed by one or two addresses behind the read address. In the case where there is a shift shown in FIG. 9, the storage address in the X direction is delayed by one or two addresses behind the read address by one or two addresses according to the moving distance of the position correspondence data (1 element or 2 elements). The storage address in the direction is advanced by one or two addresses before the read address. As a result, the positional relationships between the X-ray images that are temporally different from each other are all the same, and no image shift occurs between the images. That is, in the case of the first embodiment, the address correction processing is the image shift prevention processing.

Next, the configuration of the panel type X-ray sensor 2 will be specifically described. FIG. 10 is a schematic cross-sectional view of the X-ray sensor section of the panel X-ray sensor 2, and FIG.
FIG. 4 is a plan view of the X-ray sensor unit of FIG.

The panel type X-ray sensor 2 is provided on a semiconductor thick film 21 which is an X-ray sensitive layer in which carriers are generated by incidence of X-rays, and on the surface of the semiconductor thick film 21 on the X-ray incident side. A voltage application electrode 22; a carrier collection electrode 23 provided on the back surface of the semiconductor thick film 21 on the X-ray non-incident side; a capacitor Ca for accumulating charges collected on the carrier collection electrode 23; The switch element 24 is normally off (cut off) for extracting the charged electric charge. The thin film transistor (TFT) of the switch element 24 for extracting the electric charge is provided. The carriers are sent from the carrier collecting electrode 23 to the capacitor Ca and accumulated, and when the read timing comes, the switch element 24 is turned on (connected). ) And is accumulated charge has a configuration to be read as (X-ray) detection signal. Therefore, in the panel type X-ray sensor 2, the semiconductor thick film 21
And a part of the voltage applying electrode 22, the carrier collecting electrode 2
3. X composed of switch element 24 and capacitor Ca
X of the direct conversion type in which the line detecting elements 2a are arrayed vertically and horizontally.
It is a line sensor.

In the panel type X-ray sensor 2, the source of the thin film transistor for the switch element 24 of the detection element DU is connected to the horizontal (X) readout wiring 25, and the gate is connected to the vertical (Y) readout wiring 26. It is connected to the. The read wiring 25 is a preamplifier group (charge-voltage converter group) 2
The readout wiring 26 is connected to a gate driver 29 while being connected to a multiplexer 28 via. In the preamplifier group 27, one preamplifier (charge-voltage converter) is connected to one read wiring 25.

In the case of the panel type X-ray sensor 2, a scanning signal for signal extraction is sent from the readout control unit 8 to the multiplexer 28 and the gate driver 29. Each X-ray detecting element 2a is specified in the X direction and Y direction.
Since the scanning is performed based on the addresses (for example, 0 to 1023) sequentially assigned to the respective X-ray detection elements 2a along the array in the directions, the scanning signals for extraction are X
This signal specifies a direction address or a Y direction address. As a voltage for taking out is applied from the gate driver 29 to the readout wiring 26 in the Y direction in accordance with the scanning signal in the Y direction, each X-ray detection element 2a is selected for each column. Then, the multiplexer 28 is switched in accordance with the scanning signal in the X direction, so that the electric charge accumulated in the capacitor Ca of the X-ray detection element 2a in the selected column is sent out through the preamplifier group 27 and the multiplexer 28 in order. become.

In the case of the panel type X-ray sensor 2, the preamplifier group 27, the multiplexer 28 and the gate driver 29
Further, an AD converter (not shown) and the like are integrally installed as necessary, and the configuration is further integrated. However, all or a part of the preamplifier group 27, the multiplexer 28, the gate driver 29, the AD converter, and the like may be separately provided.

Next, the operation of the X-ray imaging apparatus of the first embodiment having the above-described configuration when performing X-ray imaging will be described with reference to the flowchart of FIG. 12 showing the progress of X-ray imaging. I will explain while. Note that the following is from the time when the subject M to be photographed is placed on the top 3 and set at the photographing position and the photographing is started. [Step S1] The subject M is irradiated with X-rays from the X-ray tube 1, and a detection signal for one image is stored in the detection signal memory 12 from the panel X-ray sensor 2.

[Step S2] The panel-type X-ray sensor 2 is moved in the predetermined direction by an amount corresponding to one position change of the X-ray detecting element 2a to the diagonally adjacent position.

[Step S3] After the detection signal of the detection signal memory 12 is corrected in accordance with the correction data of the correction data memory 15, necessary signal processing is further performed to create an X-ray image.

[Step S4] The created image is stored in the X-ray image memory 14 while the storage address is adjusted according to the positional correspondence data detected by the positional correspondence detector 18.

[Step S5] The X-ray image stored in the X-ray image memory 15 is read out and displayed on the screen of the display monitor 16.

[Step S6] If photographing is to be continued, the process returns to step S1 and the following steps are repeated. If the imaging is not to be continued, the X-ray irradiation is stopped, the subject M on the top is dropped, and the X-ray imaging is completed.

During the execution of the X-ray imaging by the X-ray imaging apparatus of the first embodiment, the screen of the display monitor 16 has no image shift in the X-ray images obtained one after another at an extremely short sampling period (for example, 30 frames / second). Although the image is updated and displayed at a high speed in the state, the X-ray images that are temporally delayed appear to the human eye due to the afterimage characteristics. On the other hand, as described above, the X-ray detection elements 2a corresponding to the same imaging point are sequentially changed among the five different elements, and each pixel signal of the X-ray image that overlaps with the human eye and moves is five. Of the X-ray detection elements 2a different from each other are averaged, and the unevenness in the intensity of the detection signal is alleviated and the influence of the fluctuation is suppressed.
The degradation of the line image quality is easily eliminated. The averaging of the relaxation of the intensity unevenness of the detection signal is not the averaging for a plurality of imaging points of the subject, but the averaging for the same imaging point of the subject. In such a case, a decrease in spatial resolution (blur of an image) that occurs at the time of image formation can be avoided.

Next, an X-ray imaging apparatus according to a second embodiment will be described. FIG. 13 is a block diagram illustrating the overall configuration of the X-ray imaging apparatus according to the second embodiment. As shown in FIG. 13, the X-ray imaging apparatus according to the second embodiment includes a buffer image memory 19 for storing a plurality of X-ray images. The plurality of X-ray images stored in the memory 19 and stored in the buffer image memory 19 are combined to form an X-ray image memory 14.
The configuration is the same as that of the first embodiment except that the image synthesizing unit 20 stored in the first embodiment is provided in the signal processing unit 13. Therefore, description of the same points as the first embodiment will be omitted, and only the differences will be described. explain. In the case of the apparatus of the second embodiment, when the number of X-ray images to be stored exceeds the number of images that can be stored in the buffer image memory 19, the oldest stored X-ray image is updated to the latest X-ray image. The oldest X-ray image is erased.

In the second embodiment, each X-ray image stored in the buffer image memory 19 is
8 is stored in a state where the storage address is adjusted in accordance with the position correspondence data detected, there is no image shift between the images stored in the buffer image memory 19. In the synthesized X-ray image obtained by synthesis by the image synthesis unit 20, since each pixel signal is obtained by averaging detection signals of several different X-ray detection elements, intensity unevenness of the detection signal is sufficiently reduced. And the effect of such fluctuations can be kept lower.

It should be noted that the image synthesizing section 20 may be configured such that each image to be synthesized is weighted and synthesized. Specifically, for example, when the X-ray image is a moving image, the latest image indicates the current state of the subject M best, so that a newer image is weighted so as to have a larger weight. , If there are large fluctuations in the images to be synthesized,
Weighting is performed such that the weight of an image having large fluctuations is reduced. Also, weighting may be performed for each pixel. For example, by reducing the weight for the averaging process for pixels that are too unstable,
The influence of the pixel can be suppressed.

The present invention is not limited to the above embodiment, but can be modified as follows. (1) In the case of the embodiment, the detection signal of the panel X-ray sensor is temporarily stored in the detection signal memory. However, the detection signal memory is not provided, and the signal processing unit converts the detection signal of the panel X-ray sensor into an image. As a modified example, an apparatus configured to directly store the image data in the X-ray image memory or the buffer image memory so as not to be displaced.

(2) In the embodiment, the panel type X-ray sensor is moved to change the position in the direction of the detection surface between the panel type X-ray sensor and the object. As a modified example, an apparatus configured to execute the change in the position in the direction of the detection surface between the panel-type X-ray sensor and the object by moving the object is described.

(3) In the case of the embodiment, the number of X-ray detection elements for detecting the same imaging point is five, but the number of X-ray detection elements for detecting the same imaging point is five. It is not limited to. Further, in the case of the embodiment, the panel-type X-ray sensor is configured to reciprocate along a straight line in an oblique direction to change the position in the detection surface direction. As a modified example, an apparatus configured to periodically move along a triangular line to change the position in the direction of the detection surface is described.

(4) The panel-type X-ray sensor of the embodiment has a two-dimensional array configuration in which a large number of X-ray detection elements are arranged vertically and horizontally, but a plurality of X-ray detection elements are arranged vertically or horizontally. 1
A configuration of a one-dimensional sensor in which only rows are arranged may be used.
Further, the panel type X-ray sensor of the embodiment is a direct conversion type, but may be an indirect conversion type sensor in which incident X-rays are first converted into light, and then converted light is converted into an electric signal. Good.

(5) The X-ray imaging apparatus according to the embodiment may have a configuration of an X-ray CT apparatus in addition to the configuration of the X-ray fluoroscopy apparatus. The radiation targeted by the present invention includes, for example, neutron rays and gamma rays in addition to X-rays.

[0045]

As described above in detail, according to the radiation detecting apparatus of the first aspect of the present invention, the same imaging point of the object is detected by the position change in the direction of the detection surface of the solid-state radiation detector by the position change executing means. The radiation detection element corresponding to the time changes every moment, and the deviation between the images due to the position change of the solid-state radiation detector is detected by the position correspondence detection means. It has a configuration that prevents it by image shift prevention processing performed according to the positional correspondence relationship, and the result is that detection signals of different radiation detection elements are averaged for each imaging point, and unevenness in detection characteristics of the detection surface is reduced. Since the influence of the fluctuation is suppressed to a low level, it is possible to easily eliminate the deterioration in the image quality of the radiographic image due to the unevenness in the intensity of the detection signal without causing the image shift between the images or the deterioration of the spatial resolution. It becomes so that.

According to the radiation imaging apparatus of the second aspect, in the signal processing by the signal processing means, there is provided a configuration in which a plurality of radiation images obtained before and after in time by image synthesis processing are synthesized. In the image obtained by the image synthesizing process, since each pixel signal is obtained by averaging detection signals of radiation detection elements different for each imaging point of the subject, unevenness of detection signal intensity is reduced over the entire image. A high quality radiation image is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of an X-ray imaging apparatus according to a first embodiment.

FIG. 2 is a schematic front view illustrating a configuration of an imaging system of the X-ray imaging apparatus according to the first embodiment.

FIG. 3 is a schematic plan view showing a detection surface of a panel type X-ray sensor of the first embodiment.

FIG. 4 is a diagram illustrating an example of a positional correspondence relationship of the same imaging point as that of a panel X-ray sensor.

FIG. 5 is a diagram illustrating another example of a positional correspondence relationship between the same imaging point as that of the panel X-ray sensor.

FIG. 6 is a diagram showing another example of the positional correspondence relationship between the same imaging point as that of the panel X-ray sensor.

FIG. 7 is a diagram showing an address arrangement of a panel X-ray sensor and a detection signal memory;

FIG. 8 is a diagram illustrating an example of an address shift between a panel-type X-ray sensor and a detection signal memory according to a change in position of a panel-type X-ray sensor in a detection surface direction.

FIG. 9 is a diagram showing another example of an address shift between the panel-type X-ray sensor and the detection signal memory due to a change in the position of the panel-type X-ray sensor in the detection surface direction.

FIG. 10 is a schematic sectional view showing an X-ray sensor section of the panel type X-ray sensor.

FIG. 11 is a plan view of an X-ray sensor unit of the panel type X-ray sensor.

FIG. 12 is a flowchart showing the progress of X-ray imaging by the apparatus of the first embodiment.

FIG. 13 is a block diagram illustrating an overall configuration of an X-ray imaging apparatus according to a second embodiment.

FIG. 14 is a schematic front view showing a configuration of an imaging system of a conventional X-ray imaging apparatus.

FIG. 15 is a diagram showing an arrangement of X-ray detection elements in an X-ray sensor of a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Top plate 2 ... Flat panel type X-ray sensor (solid-state X-ray detector) 2a ... X-ray detection element 4 ... X fine movement part 5 ... Y fine movement part 6 ... Position change control part 13 ... Signal processing part 14 ... X Line image memory 18 ... Position correspondence relation detection unit 19 ... Buffer image memory 20 ... Image synthesis unit M ... Subject

Claims (2)

[Claims] 1. A radiation irradiating means for irradiating a subject with radiation, a solid-state radiation detector for detecting transmitted radiation in which a plurality of radiation detecting elements having a radiation-sensitive film are arranged on a detection surface; Signal processing means for performing signal processing to obtain a radiation image of the subject based on the detection signal output from the radiation detector with the radiation irradiation of the radiation imaging device, between the radiation detector and the subject A position change executing means for continuously executing a position change in a direction (detection surface direction) parallel to the detection surface of the radiation detector, and a positional correspondence between the detection surface of the radiation detector and the subject in the detection surface direction is sometimes determined. And a signal processing means for detecting, at the time of signal processing, the detection surface of the radiation detector and the subject based on the positional correspondence detected by the position correspondence detecting means. Radiation imaging apparatus characterized by being configured to perform image shift blocking process of blocking the image shift that occurs between images with the positional change in the surface direction. 2. The radiation imaging apparatus according to claim 1, wherein the signal processing means is configured to also perform an image synthesis processing for synthesizing a plurality of radiation images obtained before and after in time. .