JPH08238233A - Radiographic apparatus - Google Patents

Abstract

PURPOSE: To provide a radiographic apparatus which enables reduction in withdrawing density of wiring to a scanning part from a light incident part. CONSTITUTION: This invention relates to a radiographic apparatus which is provided with an X-ray tube for exposing a subject to X rays, a detecting section in which pixels for converting light into an electrical signal are arrayed in a matrix to covert an optical image to an electrical signal, vertical shift registers 13a and 13b which are connected to the pixels separately to control the reading of signals of the pixels per line, horizontal shift registers 11a and 11b which are connected to the pixels separately to control the reading of signals of the pixels per column and a detector plate where the detecting section, the vertical shift registers 13a and 13b and the horizontal shift registers 11a and 11b are placed. At least one hand of the vertical shift registers 13a and 13b and the horizontal shift registers 11a and 11b are arranged on one side of the detecting section being divided into a plurality of systems.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray imaging apparatus for imaging a subject using X-rays, and more particularly to an X-ray imaging apparatus capable of obtaining a digital image.

[0002]

2. Description of the Related Art Mammography using X-rays has been conventionally performed. FIG. 8 is a perspective view showing a typical X-ray imaging apparatus 100 that performs mammography using X-rays. In this X-ray imaging apparatus 100, imaging is performed by bringing the breast portion into contact with the detection unit 101 as shown in FIG.

Films have been used for mammography using X-rays. The main purpose of this mammography is to detect breast cancer, for which microcalcification (100-300μ)
m, high contrast) and tumor (~ several cm, low contrast) must be well represented.

[0004] However, although microcalcification can be easily detected by mammography using the above-mentioned film, it is difficult to detect a tumor having a small contrast. Therefore, there is a strong demand for increasing the detection rate of tumors by image processing with digital images. Moreover, not only the breast but also the chest and other parts have similar strong demands.

Currently, as means for obtaining digital images,
CR (computed radiograph) using an imaging plate that scans a laser beam after imaging on the imaging plate and detects the emitted light to digitize
y) is done in part. However, this has the drawback that the resolution is low and the ability to visualize microcalcifications is not good, and the light emitted from the laser beam after scanning is detected and digitized. It has a drawback that it takes time, and therefore it takes time from photographing to observing the image.

For this reason, there is a demand for a detector having a high resolution, which allows image observation immediately after photographing and digital image processing. As a detector that meets such expectations, as shown in FIG. 9, a support 111, a SiN 113, and a
-Si115, and a TFT (thin film) including a gate 117, a source 119, a drain 121, and a polyimide 123.
Film Transistor) 125 and photodiode 127
And a detector 131 including a phosphor 129 are proposed. Note that FIG. 9 shows a cross-sectional configuration of one pixel of the detector 131.

In the detector 131, X emitted from an X-ray tube (not shown), transmitted through the subject, and made incident on the phosphor 129.
The lines are converted to visible light. This visible light is incident on the photodiode 127 to generate charges. This charge is TF
It is read out by turning on T125.
In the detector 131, the photodiode 127 is also the TFT1.
Since 25 is also formed of a thin film of a-Si115, it can be a detector having a wide field of view.

Next, the operating principle of the detector 131 will be briefly described with reference to FIG. Note that FIG. 10 is a plan view of the detector 131 without the phosphor 129. First, the photodiode 127 is reverse biased and the associated capacitance 13
Charge 3 The electric charge generated by the visible light entering the photodiode 127 discharges the electric charge accumulated in the capacitance 133. After the discharge is completed, the horizontal shift register 135 and the vertical shift register 137 select each of the TFTs 125 to read out the electric charges to the outside and charge the electrostatic capacitance 133 again. Here, the discharge amount is proportional to the amount of light incident on the photodiode 127. Therefore, a digital image can be obtained based on the read charges.

[0009]

However, when high resolution is required such as mammography for the purpose of finding breast cancer, the arrangement pitch of the detectors 133a composed of the TFTs 125, the photodiodes 127, and the capacitances 133 is set. Since it is necessary to narrow the width (for example, 50 μm pitch), the wiring from the detection unit 133a to the scanning unit such as the horizontal shift register 135 and the vertical shift register 137 has a very high extraction density, which makes it difficult to extract the wiring. There's a problem.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an X-ray imaging apparatus capable of reducing the extraction density of the wiring from the detection section to the scanning section. .

[0011]

In order to achieve the above object, the present invention provides an X-ray tube for irradiating a subject with X-rays and an X-ray image transmitted through the subject into an optical image. An X-ray-light conversion unit and pixels for converting light into an electric signal are arranged in a matrix, and a detection unit for converting the optical image into an electric signal is connected to each of the pixels and arranged in the matrix. A vertical scanning unit for controlling pixel signal readout for each row;
A horizontal scanning unit that is connected to each of the pixels and controls signal reading of the pixels arranged in the matrix for each column, and a detector plate on which the detection unit, the vertical scanning unit, and the horizontal scanning unit are mounted. Further, in the X-ray imaging apparatus, at least one of the horizontal scanning unit and the vertical scanning unit is provided on one side surface side of the imaging unit in a plurality of groups separately.

Further, the detector plate is characterized in that the detecting portion is brought closer to the side where the subject is located. further,
An X-ray-light conversion unit that converts X-rays into visible light, a pixel that converts light into an electric signal are arranged in a matrix, and a detection unit that converts the visible light into an electric signal, and a conversion unit In an X-ray imaging apparatus including a detector including a scanning unit that reads out an electric signal, the detector is
At least on the side where the subject is located, the scanning section is not provided, and the pixels are provided to the end as much as possible.

[0013]

According to the above construction, at least the horizontal scanning section for controlling the signal reading of the pixels arranged in a matrix for each column and the vertical scanning section for controlling the signal reading of the pixels arranged in a matrix for each row. One of them is provided on one side surface side of the detection unit, divided into a plurality of series. This allows
The wiring extraction density from the pixel to the horizontal scanning unit and the vertical scanning unit is reduced.

Further, an X-ray-light conversion unit for converting X-rays into visible light, a pixel for converting light into an electric signal are arranged in a matrix, and a detection unit for converting the visible light into an electric signal, and detection. In an X-ray imaging apparatus including a detector including a scanning unit that reads out an electric signal converted by the scanning unit, the scanning unit may not be provided at least on the side of the detector where the subject is located. As long as the pixels are provided up to the end portion thereof, there is almost no area that may not be detected.

[0015]

1 is a plan view showing a detector 10 of an X-ray imaging apparatus according to a first embodiment of the X-ray imaging apparatus according to the present invention (excluding a phosphor). The same members as those of the conventional detector 131 shown in FIGS. 8 and 9 are designated by the same reference numerals, and the description thereof will be omitted. Further, the cross-sectional structure of one pixel on the incident surface of the detector 10 is the same as that of the conventional detector 131 shown in FIG.
Illustration and description are omitted.

Conventionally, the charge stored in the electrostatic capacitance 133 is read out by one horizontal shift register 135 and one vertical shift register 137 (see FIG. 9). The detector 10 is shown in FIG.
Two horizontal shift registers 11a and 11b as shown in FIG.
And the two vertical shift registers 13a and 13b are used to alternately read out the charges. In addition,
Other parts have the same configuration as the conventional detector 131 shown in FIG.

In the detector 10 of the X-ray imaging apparatus of the first embodiment, as shown in FIG.
25, the photodiode 127 and the electrostatic capacity 133, the horizontal shift register 11a and the horizontal shift register 11b are provided respectively adjacent to the two sides in the horizontal direction of the substantially rectangular detection unit 133a.
A vertical shift register 13a and a vertical shift register 11b are provided adjacent to two vertical sides of 33a.

The horizontal shift register 11a is in charge of reading charges from the electrostatic capacitors 133 in odd columns, and the horizontal shift register 11b is in charge of reading charges from the electrostatic capacitors 133 in even columns. Also, the vertical shift register 13a is
The vertical shift register 13b is in charge of reading charges of the electrostatic capacitors 133 in the odd-numbered rows, and the vertical shift register 13b is in charge of reading charges of the electrostatic capacitors 133 in the even-numbered rows.

The horizontal shift registers 11a and 11b and the vertical shift registers 13a and 13b are collectively driven by a drive controller (not shown). The timing of driving the horizontal shift registers 11a and 11b and the vertical shift registers 13a and 13b by the drive controller is shown in FIG.
As shown in FIG. 2, the vertical shift register 13a outputs 1
The second row is driven by the vertical shift register 13b, the second row is driven by the horizontal shift register 11a, the first row is driven by the horizontal shift register 11a, and the first row is driven by the horizontal shift register. If the horizontal shift register 11a and the horizontal shift register 11b are driven at the same time as shown in FIG. 3, the read speed is doubled.

As described above, the detector 10 of the X-ray imaging apparatus of the first embodiment has the TFT 125 and the photodiode 127.
And the electric charge charged in the electrostatic capacity 133 of the detection unit 133a composed of the electrostatic capacity 133 is converted into two horizontal shift registers 11a and 11b and two vertical shift registers 13a and 1b.
3b is used to read alternately, so that the shift registers (horizontal shift registers 11a and 11b, vertical shift register 13) from the detection unit 133a to the scanning unit are used.
It is possible to reduce the extraction density of the wiring to a, 13b).

The detector 10 of the X-ray imaging apparatus of the first embodiment uses a shift register (horizontal shift registers 11a, 11) to read out the charges accumulated in the capacitance 133.
b, vertical shift registers 13a13b) are used, but the present invention is not limited to this. For example, as shown in FIG. 4, instead of the vertical shift registers 13a and 13b, the output amplifier 21 is used.
With input side multiplexers 23a and 23b, respectively.
May be used.

Further, the detector 10 of the X-ray imaging apparatus of the first embodiment is provided with two shift registers (horizontal shift registers 11a and 11b and vertical shift registers 13a and 13b) both in the horizontal and vertical directions. However, not limited to this, two shift registers may be provided only in the horizontal direction or the vertical direction.

Further, the detector 10 of the X-ray imaging apparatus of the first embodiment is provided with two shift registers (horizontal shift registers 11a and 11b and vertical shift registers 13a and 13b) both in the horizontal and vertical directions. , The extraction density of the wiring from the detection unit 133a to the shift register is reduced, but not limited to this, for example, as shown in FIG. 5, four shift registers (horizontal shift Registers 11a, 11b,
11c and 11d, vertical shift registers 13a and 13b,
13c, 13d) may be provided. The number of shift registers is not limited to this. The added shift register does not have to be provided adjacent to the existing shift register, but may be provided on the back surface of the substrate or the like.

FIG. 6 shows a second X-ray imaging apparatus according to the present invention.
It is a top view which shows the detector 30 of the X-ray imaging apparatus of an Example (a fluorescent substance is excluded). The same members as those of the X-ray imaging apparatus of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. Further, the cross-sectional structure of one pixel on the incident surface of the detector 30 is the same as that of the conventional detector 131 shown in FIG.
Illustration and description are omitted.

In the mammography by the X-ray imaging apparatus, the breast is positioned corresponding to the detector 101 as shown in FIG. Therefore, like the detector 30 of the X-ray imaging apparatus of the first embodiment shown in FIG. 1, the four sides of the detection unit 133a are adjacent to each other in shift registers (horizontal shift registers 11a, 11).
b, when the vertical shift register 13a13b) is provided,
Since the vertical shift register 13b exists on the side where the breast is located, the area where the vertical shift register 13b exists may not be detected. To eliminate this, the second
In the detector 30 of the X-ray imaging apparatus of the embodiment, as shown in FIG. 6, the vertical shift register 13b is moved to the vertical shift register 13a side, and the detection unit 133 including the TFT 125, the photodiode 127 and the electrostatic capacity 133 is provided.
a is provided as far as possible on the side where the vertical shift register 13b is conventionally provided (side near the ribs of the breast on the side of the number of images taken).

FIG. 7 is a plan view (FIG. 7 (a)) and a front view (FIG. 7 (b)) when mammography is actually performed using the detector 30 of the X-ray imaging apparatus of the second embodiment. ) Is shown.
As shown in FIG. 7A, in the mammography using the detector 30 of the X-ray imaging apparatus of the second embodiment, the breast is placed on the detector plate 30a holding the detector 30, and It is performed by fixing the breast using a compression plate from above. here,
Since the detector 30 of the X-ray imaging apparatus of the second embodiment is provided with the X-ray detection unit as far as possible on one side of the X-ray detection unit 133a, the breast is placed on the one side. By doing so, it is possible to almost eliminate the area that may not be detected.

In the detector 30 of the X-ray imaging apparatus of the second embodiment, the vertical shift register 13b is moved to the vertical shift register 13a side, but the invention is not limited to this, and the side on which the breast is positioned is the vertical shift register 13a. If you are on the side,
The vertical shift register 13a is replaced with the vertical shift register 13b.
Try to move to the side. Also, the side on which the breast is positioned is the horizontal shift register 11a or the horizontal shift register 11
If it is on the b side, the horizontal shift register 11a or the horizontal shift register 11b is moved to one side.

Further, the detector 30 of the X-ray imaging apparatus of the second embodiment has two shift registers (horizontal shift register) in both the horizontal and vertical directions like the detector 10 of the X-ray imaging apparatus of the first embodiment. 11a, 11b, vertical shift registers 13a, 13b) are provided, but not limited to this.
In the horizontal direction and the vertical direction, only one shift register may be provided on the side where the breast is located, as in the conventional case. For example, in the case of the detector 30 shown in FIG. 6, one shift register is used in the vertical direction.

Further, the case where the detectors 10 and 30 of the X-ray imaging apparatus of the first embodiment and the second embodiment are both applied to mammography has been described, but the present invention is not limited to this and is also applied to other parts. be able to.

[0030]

As described above, according to the present invention, the horizontal scanning unit for controlling the signal reading of pixels arranged in a matrix for each column and the signal reading of pixels arranged in a matrix for each row. Since at least one of the vertical scanning units to be controlled is provided on one side surface side of the detection unit in a plurality of groups, it is possible to reduce the wiring extraction density from the pixels to the horizontal scanning unit and the vertical scanning unit. it can.

In addition, since a scanning unit is not provided and pixels are provided as far as possible to the edge of the detector at least on the side where the subject is located, an image of the rib side of the breast is taken. It is possible to eliminate an area that may not be detected.

[Brief description of drawings]

FIG. 1 is a plan view showing a detector of an X-ray imaging apparatus of a first embodiment of an X-ray imaging apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing timings of driving a horizontal shift register and a vertical shift register by a drive controller.

FIG. 3 is an explanatory diagram showing a timing of driving a horizontal shift register and a vertical shift register by a drive controller (simultaneous reading of only the horizontal shift register).

FIG. 4 is a plan view showing a detector in the case of providing a multiplexer having an output amplifier on the input side instead of the vertical shift register.

FIG. 5 is a plan view showing a detector when four shift registers are provided in both the horizontal and vertical directions.

FIG. 6 is a plan view showing a detector of the X-ray imaging apparatus of the second embodiment of the X-ray imaging apparatus according to the present invention.

FIG. 7 is a detector 30 of the X-ray imaging apparatus of the embodiment shown in FIG.
FIG. 3 is a plan view (a) and a front view (b) showing a case where mammography is actually performed by using FIG.

FIG. 8 is a perspective view showing a typical X-ray imaging apparatus that performs mammography using X-rays.

FIG. 9 is an explanatory diagram showing a cross-sectional configuration of one pixel of the detector.

FIG. 10 is a plan view showing a conventional detector of an X-ray imaging apparatus.

[Explanation of symbols]

 10, 30 Detector 11 Horizontal shift register 13 Vertical shift register 21 Output amplifier 23 Multiplexer 100 X-ray imaging device 111 Support 113 SiN 115 a-Si 117 Gate 119 Source 121 Drain 123 Polyimide 125 TFT 127 Photodiode 129 Phosphor 131 Detection Vessel 133 capacitance

Claims (3)

[Claims] 1. An X-ray tube that irradiates an object with X-rays, an X-ray-light conversion unit that converts an X-ray image transmitted through the object into an optical image, and a pixel that converts light into an electrical signal. Are arranged in a matrix,
A detection unit that converts the optical image into an electric signal, a vertical scanning unit that is connected to each of the pixels and controls signal readout of the pixels arranged in the matrix for each row, and is connected to each of the pixels, An X-ray imaging apparatus comprising: a horizontal scanning unit that controls signal readout of pixels arranged in a matrix for each column; and a detector plate on which the detection unit, the vertical scanning unit, and the horizontal scanning unit are mounted, An X-ray imaging apparatus, wherein at least one of the horizontal scanning unit and the vertical scanning unit is provided on one side surface side of the detection unit in a plurality of groups. 2. The X according to claim 1, wherein the detector plate is arranged such that the detection unit is located closer to the side where the subject is located.
X-ray equipment. 3. An X-ray-light conversion unit for converting X-rays into visible light, a pixel for converting light into an electric signal are arranged in a matrix, and a detection unit for converting the visible light into an electric signal. In an X-ray imaging apparatus including a detector including a scanning unit that reads out an electric signal converted by a scanning unit, the scanning unit may not be provided at least on the side of the detector where the object is located. An X-ray imaging apparatus characterized in that the pixels are provided up to the end thereof.