JPH0767863A - X-ray image pickup device - Google Patents

Abstract

PURPOSE:To provide the X-ray image pickup device capable of making high- speed macrophotography. CONSTITUTION:X-ray radiographic images are formed on the bases of the optical images obtd. from X-rays transmitted through an examinee. This device has an image pickup element 5 which constitutes an image pickup plane 5b by two-dimensionally arranged pixel 5a to 5a groups and receives the optical images by these pixels 5a to 5a and a reading out region setting circuit 12b for setting the reading out region of the image pickup plane 5b. The device has a vertical shift register 11a and horizontal shift register 11b which scan the pixels 5a to 5a corresponding to the reading out region set by this reading out region setting circuit 12b in accordance with the control of a scanning control circuit 12a and output the resulted signals as the X-ray radiographic images for each of the respective pixels 5a.

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 making various diagnoses based on an X-ray fluoroscopic image obtained from X-rays transmitted through a patient, and more particularly to a two-dimensional array of light receiving elements. The present invention relates to an X-ray imaging device including the above-described light receiving element group as an imaging element.

[0002]

2. Description of the Related Art As an X-ray imaging apparatus, for example, X
It is known that a line is irradiated and an X-ray fluoroscopic image obtained from the transmitted X-ray is displayed on a TV monitor for diagnosis. Such an X-ray imaging apparatus can observe the movement of the catheter inside the subject, the flow of the contrast agent, and the like through a monitor, and is used for various diagnoses.

An X-ray fluoroscopic image shows an X-ray transmitted through a patient.
Image intensifier (hereinafter referred to as II)
The optical image is converted into an image signal by a TV camera, and the obtained optical image is converted into an image signal by a TV camera. As a TV camera, an image pickup tube such as Sachicon or Carnicon was used before, but recently, a solid-state image pickup element such as CCD is widely used instead of the image pickup tube. This solid-state image pickup device has excellent features such as good resolution, wide dynamic range, and no afterimage in addition to small size, light weight, and low power consumption.

The X-ray image pickup device is provided with a two-dimensionally arrayed light receiving element (forming a pixel) as a solid-state image pickup element, and a CCD image sensor (IT (Interline Transfer) type) scanning method of this pixel ( Hereinafter, simply referred to as CCD) is generally used.

An X-ray image pickup device using such an IT type CCD is shown in FIGS.

As shown in FIG. 4, the X-rays emitted from the X-ray tube 20 are emitted toward the patient H while being focused by the X-ray diaphragm 21. The X-rays transmitted through the patient H are I.P. I.
22 and the optical system 23 to convert it into an optical image, and the optical image is photoelectrically converted by the two-dimensionally arranged light receiving elements 25 ... 25 such as photodiodes formed on the imaging surface 24a (see FIG. 5) of the CCD 24. .

Charges accumulated in the light receiving elements, that is, the pixels 25 ... 25 by this photoelectric conversion are, as shown in FIG. 5, made parallel to the pixel row based on a control signal φ from a CCU (Camera Controul Unit) 26. The adjacent vertical transfer CCDs 27 perform high-speed transfer in the direction of arrow s1 (vertical direction), and based on the control signal φ from the CCU 26, the horizontal transfer CCD 28 moves in the direction of arrow s2 (horizontal direction). High speed transfer.

The charges thus horizontally transferred are amplified by the amplifier 29.
Is amplified and output as an image signal. This image signal is converted into a digital image signal by the A / D converter 30, and then, for example, an image processing circuit 31 including an image memory.
According to need, various image processes are performed.

The output signal from the image processing circuit 31 is converted into an analog image signal by the D / A converter 32, and is displayed on the TV monitor 33.

[0010]

By the way, the CCD is usually designed and manufactured on the premise that 30 images (30 images / sec) are read per second due to the limitation of the driving frequency of the horizontal transfer CCD. Further, in the IT type CCD, the next frame image cannot be read unless all pixels on the image pickup surface are read because of its structure (that is, reading with setting a partial area cannot be performed).

On the other hand, for a fast-moving subject such as a child's heart, if 120 images (120 images / sec) for 1 second can be read out at a higher speed only in the fast-moving region, for diagnostic purposes. More advantageous.

However, in the conventional X-ray image pickup device using the IT type CCD, all the pixels on the image pickup surface must be read out at all times, and the image reading speed is 3
Since the number of images is 0 / sec, it was not possible to sufficiently deal with the above-described fast-moving subject.

Further, in order to solve the above-mentioned problems, it is considered to read out the pixels on the image pickup plane by superposing a plurality of rows, but there is a limit to the amount of charge that the horizontal transfer CCD can hold, so that it is sufficient for speeding up. It was not something I could handle.

Further, in the X-ray imaging apparatus using the IT type CCD, when it is desired to magnify and photograph a region E of the subject as shown in FIG. 6 (enlarged photographing), only this region E needs to be read. However, it is impossible to read out the area set by the IT type CCD. For this reason, all the pixels are read out and then temporarily stored in the image memory of the image processing circuit or the like, and substantial enlargement photographing is realized by a method such as devising the reading from the memory. Nevertheless, all the pixels are read out and further processed by the image processing circuit, which increases the processing time and is troublesome.

The present invention has been made in view of the above-mentioned problems, and provides an X-ray imaging apparatus capable of performing high-speed and magnified imaging quickly and easily by making it possible to read out area setting. With the goal.

[0016]

In order to solve the above-mentioned object, an X-ray imaging apparatus according to claim 1 is a conversion for converting an X-ray exposed from an X-ray tube and transmitted through the subject into an optical image. In the X-ray imaging apparatus, which is provided with a means, forms an X-ray fluoroscopic image from the optical image, and displays the X-ray fluoroscopic image on a monitor, the imaging surface is configured by a light receiving element group arranged two-dimensionally. In addition, the image pickup means for receiving the optical image by the light receiving element, the read area setting means for setting the read area of the image pickup surface, and the light receiving element corresponding to the read area set by the read area setting means are scanned. The scanning means is provided for outputting the signal obtained by this scanning as an X-ray fluoroscopic image for each light receiving element.

Particularly, in the X-ray imaging apparatus according to the second aspect, X-ray diaphragm means for narrowing down the X-rays which are irradiated from the X-ray tube to the subject, and the X-ray diaphragm amount by the X-ray diaphragm means. And X-ray diaphragm control means for controlling the X-ray corresponding to the readout area.

[0018]

According to the X-ray imaging apparatus of the present invention, the X-rays emitted from the X-ray tube toward the subject and transmitted through the subject are converted into an optical image and then arranged in a two-dimensional array. The light is received by the image pickup surface of the image pickup means constituted by the group.

Now, for the sake of diagnosis, it is assumed that a specific portion of the subject is to be imaged at high speed (or enlarged).

At this time, the area on the image pickup surface corresponding to the specific portion is set as the reading area by the reading area setting means based on the input from the operator and the reading area information is sent to the scanning means. The scanning means scans the light-receiving element corresponding to the sent read area, and the signal obtained as a result is output as an X-ray fluoroscopic image for each light-receiving element.

Particularly, in the X-ray imaging apparatus according to claim 2,
The X-ray tube is provided with X-ray diaphragm means for narrowing down the X-rays emitted from the X-ray tube to the subject, and X-ray diaphragm means for controlling the X-ray diaphragm amount of the X-ray diaphragm means. The X-ray aperture control unit controls the X-ray irradiating amount so that the X-ray exposure amount becomes the amount according to the reading region set by the reading region setting unit.
The diaphragm amount of the line diaphragm means is controlled.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the X-ray imaging apparatus according to the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing the arrangement of the X-ray imaging apparatus of this embodiment.

The X-ray imaging apparatus shown in FIG. 1 includes an X-ray tube 1 for generating X-rays and an X-ray diaphragm 2 which is an X-ray diaphragm means for narrowing the generated X-rays to prevent exposure to unnecessary portions. And an image intensifier (hereinafter referred to as II) 3 for converting the X-rays transmitted through the patient H into an optical image, and an optical system 4 for correcting the converted optical image to an appropriate size and intensity. And an XY addressing type image pickup device 5 for converting the corrected optical image into an image signal. In addition, I. I. The optical system 3 and the optical system 4 compose the conversion means described in claim 1, and the image pickup device 5 composes the imaging means described in claim 1.

Further, the X-ray image pickup apparatus includes an A / D converter 6 for converting the image signal converted by the image pickup element 5 into a digital image signal, and various image processing for the digital image signal as necessary. An image processing circuit 7 for performing the image processing, a D / A converter 8 for converting the image-processed digital image signal into an analog image signal, and a TV monitor 9 for displaying the analog image signal as an X-ray transmission image. ing. It should be noted that the image signal output from the image sensor 5 is directly transmitted to the T
A configuration in which the X-ray transmission image is displayed by inputting to the V monitor 9 is also possible.

On the other hand, the image pickup device 5 is, as shown in FIG.
For example, an embedded MOS transistor 5a (hereinafter simply referred to as a MOS, which is a light receiving element having a ring-shaped gate electrode).
A transistor) is, for example, 1024 × 1024
Individually arranged in a square shape. The MOS transistor 5a has a two-dimensional address {(r, s); 1 ≦
The image pickup surface 5b is formed as a whole as a pixel having r, s ≧ 1024} (hereinafter, this configuration will be referred to as an embedded MO).
S image sensor). The image pickup surface 5b corresponds to the image display surface of the TV monitor 9.

Further, the image pickup device 5 is an MO of a predetermined address.
A vertical shift register 11a and a horizontal shift register 11b capable of selectively scanning the S transistor 5a are provided.

Further, the image pickup device 5 includes a CCU (Camera C
ontroul Unit) 12 is connected. CCU12 is
Vertical shift register 11a and horizontal shift register 11
The scanning control circuit 12a for controlling the selective scanning of b and the reading area in the imaging surface 5b is set according to the input from the operator or the like, and the scanning control circuit 1 is set as the reading area information F.
And a read area setting circuit 12b for outputting to 2a.

The read-out area setting circuit 12b has a memory and outputs an area (that is, a designated pixel area) designated by a cursor on the TV monitor 9 by an operator or the like as a two-dimensional address on the image pickup surface 5b.

The scan control circuit 12a controls the drive signal φ to the vertical shift register 11a and the horizontal shift register 11b so that only the pixel at the address designated by the read area setting circuit 12b is scanned. To do.

On the other hand, the X-ray imaging apparatus controls the aperture amount of the X-ray aperture 2 so that the X-ray is not exposed outside the readout area set by the readout area setting circuit 12b.
An X-ray diaphragm control device 13, which is an X-ray diaphragm control means, is provided.

The vertical shift register 11a, the horizontal shift register 11b, and the scanning control circuit 12a constitute the scanning means according to claim 1, and the reading area setting circuit 12 is provided.
b constitutes the read area setting means.

Next, the overall operation of this embodiment will be described.

In the X-ray imaging apparatus, the subject H is measured from the X-ray tube 1.
The X-rays that have been exposed to the
I. I. It is converted into an optical image of a predetermined size by 3 and the optical system 4. This optical image is usually received by the entire image pickup surface 5b of the image pickup element 5 to form an X-ray fluoroscopic image. Then, this X-ray fluoroscopic image is displayed on the TV monitor 9 after being subjected to image processing as necessary.

Here, for convenience of diagnosis, for example, the TV monitor 9
It is assumed that the image displayed in the substantially central portion (the area surrounded by the broken line in the central portion in FIG. 3 (for example, the number of pixels 512 × 512); the readout area E) is to be displayed at particularly high speed. At this time, the operator specifies an area (readout area E) to be displayed as an address value via the readout area setting circuit 12b. That is, in the read area setting circuit 12b, addresses adr1 (257,257) to adr2 (257,768) to adr3 (7
68,257)) to adr4 (768,768) are generated, and the designated address is used for the X-ray diaphragm controller 13 and the scan controller 12.
is output to a.

The X-ray diaphragm control device 13 controls the diaphragm amount of the X-ray diaphragm 2 so that the X-rays are not exposed to the outside of the read-out area E addressed.

On the other hand, the scanning control circuit 12a controls the drive signal φ to the vertical shift register 11a and the horizontal shift register 11b. This allows the vertical shift register 1
1a and the switching signal r267 for scanning the pixels 5a ... 5a at the specified address from the horizontal shift register 11b
.About.r768 and s267 to s768 are output.

As a result, the switching signals r267 to r768
And s267 to s768, the pixel 5a of the readout area E
5a is sequentially scanned for each pixel to read out electric charges,
This charge is output as an image signal.

In this case, assuming that the pixel scanning speed does not change, conventionally, the time required to read out a partial “512 × 512” pixel area is the whole pixel area (1024 × 512).
1024) was the same as the read time, but for this configuration, by reading pixels in the region to be read out (512 × 512) directly, be the speed of about four times (1024 ^{2/512 2)} it can.

Further, the read area of the image pickup device is set,
Since only this area can be directly read out, it is possible to perform magnified photographing at high speed without reading out all pixels and without performing image processing.

Further, the aperture amount of the X-ray diaphragm is controlled corresponding to the set read-out area, and the X-ray outside the read-out area is controlled.
By preventing radiation exposure, unnecessary X-ray exposure can be reduced.

In this embodiment, the X-ray diaphragms 2 and X
The line diaphragm control means 13 may be removed as necessary.

Further, in the present embodiment, the address indicating the read area is stored in advance in the memory of the read area setting circuit and is set so that the stored address can be automatically read out. High-speed photography and magnified photography can be performed.

Further, although the embedded MOS image sensor is used as the image pickup device in the present embodiment, the present invention is not limited to this, and an XY address system such as an image pickup device using a normal MOS transistor is used. Any image sensor may be used.

[0045]

As described above, according to the X-ray imaging apparatus of the first aspect, an area of a portion of high diagnostic interest, such as a fast-moving portion, is set as the reading area, and only this reading area is set. Since the image can be taken, it is possible to take high-speed or magnified images of a region of high diagnostic interest.

Particularly, in the X-ray imaging apparatus according to claim 2,
When setting a region of high diagnostic interest as a read-out region, X-rays can be narrowed down to prevent X-rays from being exposed to areas other than the read-out region. It is possible to further improve the sex.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an X-ray imaging apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a part of the configuration of an image sensor.

FIG. 3 is a diagram illustrating an example of partial reading according to the present embodiment in association with pixel regions.

FIG. 4 is a block diagram showing a schematic configuration of a conventional X-ray imaging apparatus.

FIG. 5 is a schematic configuration diagram showing an example of a conventional image sensor.

FIG. 6 is a diagram illustrating a state of an image pickup surface in enlarged shooting.

[Explanation of symbols]

 1 X-ray tube 2 X-ray diaphragm device 3 I. I. 4 Optical system 5 Image sensor 5a MOS transistor (pixel) 5b Imaging surface 6 A / D converter 7 Image processing circuit 8 D / A converter 9 TV monitor 11a Vertical shift register 11b Horizontal shift register 12a Scan control circuit 12b Read control circuit 13 X-ray diaphragm control device

Claims (2)

[Claims] 1. An X-ray fluoroscopic image is formed from the optical image by including a conversion unit that converts the X-ray exposed from the X-ray tube and transmitted through the subject into an optical image. In an X-ray image pickup device for displaying on a monitor, an image pickup surface is constituted by a light receiving element group which is arranged two-dimensionally, and an image pickup means for receiving the optical image by the light receiving element, and reading of the image pickup surface. The reading area setting means for setting the area and the light receiving element corresponding to the reading area set by the reading area setting means are scanned, and the signal obtained by this scanning is output as an X-ray fluoroscopic image for each light receiving element. An X-ray imaging apparatus comprising a scanning unit. 2. An X-ray diaphragm means for narrowing down the X-rays that are exposed to the subject from the X-ray tube, and X by the X-ray diaphragm means.
The X-ray imaging apparatus according to claim 1, further comprising: an X-ray diaphragm control unit that controls a line diaphragm amount corresponding to the readout area.