JP3356334B2 - X-ray equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an X-ray imaging apparatus, in particular, Ta suitable X-ray imaging that require high viewing as chest
It relates to a shadow device .

[0002]

2. Description of the Related Art Conventionally, as a method of taking an X-ray image by dividing a chest into a plurality of times while changing a relative position between an X-ray detection system and a subject, for example, "Medical Electronics and Biotechnology. Vol. 31 Special Issue (Transactions of the 32nd Annual Meeting of the MM Society of Japan), p. 209,
The technique shown in "May 1993" is known. This technology uses an X-ray television camera composed of an X-ray image intensifier and a television camera as an X-ray detection system,
The subject's radiographing position is upright, the X-ray source is fixed, and the left and right lung fields are separately divided and photographed by a method in which the X-ray detection system is moved in a straight line in one direction with respect to the subject. The two images obtained are combined and displayed. As a method of performing ECG synchronization in X-ray imaging, for example,
A technique relating to angiography disclosed in Japanese Patent No. 4439 is known.

[0003]

When a plurality of images are taken of the chest, the shape of the heart is generally different in a plurality of images as the heart beats, and the positions of the mediastinum and the lungs are generally different. As a result, discontinuity occurs at the joint in the synthesized image, which is not preferable for diagnosis. The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the above-described problems in the related art, to avoid the deformation of the heart in a plurality of images, etc. By eliminating discontinuities and enabling accurate joining of images, it is possible to capture a chest with a high spatial resolution over a wider area than the field of view of the X-ray detection system
An object of the present invention is to provide an X-ray imaging apparatus .

[0004]

Means for Solving the Problems To achieve the above object,
The X-ray imaging apparatus of the present invention passes through the X-ray tube and the subject.
X-ray detection system that detects the X-rays
Movement mechanism to move and collect output signal of the X-ray detection system
Processing device for performing an operation to obtain an image of the subject
A display device for displaying the image; an electrocardiograph;
One lung and the mediastinum of the specimen are placed in the field of view of the X-ray detection system.
First X-ray imaging to be performed and moving the X-ray detection system
Put the other lung and mediastinum in the field of view of the X-ray detection system
The second imaging performed is performed by a predetermined same of the output signal of the electrocardiograph.
An imaging control device that performs the imaging in the phase state of
The system is X-ray imaging intensifier, TV camera
And an electron beam reader for an image pickup tube of the television camera.
After stopping scan-out scanning for a predetermined time, the second photographing is performed.
It is characterized by reading the image obtained by the shadow
ing.

[0005]

In the X-ray imaging apparatus according to the present invention, a plurality of imagings are performed in a predetermined same phase state of the electrocardiogram signal, thereby accommodating the heartbeat between the plurality of imagings. Heart, mediastinal and lung movements are compensated for, and the accuracy of image joining is improved. In particular, by performing imaging in a state in which the phase state of the electrocardiographic signal is the end-systole of the heart, the speed of movement of the heart is minimized. The movement is minimal, and as a result, a clear captured image is obtained. In addition, since the volume of the heart is minimum, the portion of the lung field that overlaps the heart on the captured image is minimized, and as a result, the performance of detecting a lesion in the lung field is improved. In the X-ray imaging apparatus according to the present invention, by using an imaging tube as a television camera,
For example, high-speed shooting of 1050 shots and high-resolution shooting of 2100 scanning lines can be performed by selecting a camera mode. In addition, by reading out the second captured image for a predetermined time after stopping the electron beam readout scanning, it is possible to avoid deterioration in image quality due to microphonic noise generated due to movement of the detection system. . In the X-ray imaging apparatus according to the present invention, when a CCD camera is used as a television camera, no microphonic noise is generated even when the detection system is moved. The movement of the detection system can be performed at the same time. As a result, the time interval between the first imaging and the second imaging can be reduced, and imaging can be performed with continuous heartbeats. More specifically, in the digital radiography for the chest (DR), the X-ray detection system is performed by performing two imagings in the same phase state of the electrocardiogram signal and performing image joining accurately. X-rays can be taken with high spatial resolution over a range wider than the visual field of the subject.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows a chest X according to an embodiment of the present invention.
It is a side view which shows the schematic structure of a radiography apparatus. The chest X-ray imaging apparatus according to the present embodiment includes an imaging control device 1, an X-ray tube high voltage generator 2, an X-ray tube 3, an X-ray filter 4, an X-ray slit 5, an X-ray grid 6, and an X-ray image. Intensifier 7, optical lens system 8, optical aperture 9, television camera 10, image collection / processing device 11, image display device 12,
It comprises a recording device 13, a moving mechanism 14 for moving the X-ray detection system 16 indicated by a dashed box, a movement control device 15, an X-ray shielding plate 21, an electrocardiograph 31, an R-wave detector 32, and the like. The imaging position of the subject 17 is standing. The TV camera 10 can scan 1050 lines, 2100 lines, and 4200 lines. As the electrocardiograph 31, various types of electrocardiographs used for electrocardiographic measurement can be used.

FIG. 3 is a top view showing a schematic configuration of an imaging system of the X-ray imaging apparatus. The present apparatus is an apparatus for imaging the chest by two imagings, and the A position and the B position indicate the position of the detection system at the time of the imaging, and are the first imaging position and the second imaging position, respectively. Position A is a position where the detection system covers the area of one lung and the mediastinum, and position B is a position where the detection system covers the other lung and the mediastinum. Representative examples of the A position and the B position are positions left and right of 85 mm from the body axis, respectively. In FIG. 3, reference numeral 5-1 denotes a portion of the X-ray slit 5, which limits the X-ray emission range in the horizontal direction. The horizontal X-ray emission range moves in accordance with the position of the detection system. The slits for limiting the X-ray emission range in the vertical direction are not shown in FIG. The details of the electrocardiographic measurement can be referred to, for example, the description of “Basic of Pharmaceutical and Pharmaceutical Sciences I (Mix, 1981)”.

The outline of the function of each unit described above is as follows. The electrocardiograph 31 obtains an electrocardiogram signal of the subject 17 and
The wave detector 32 determines an electrocardiogram synchronization signal based on the electrocardiogram signal. The imaging control device 1 moves the X-ray detection system 16 to two predetermined positions (A
Position and B position), an imaging sequence for X-ray imaging, that is, a pulse width and a pulse interval of two X-ray pulses, a high voltage (X-ray tube voltage), a tube current, an operation mode of a television camera, an X-ray slit 5-1 opening movement sequence,
Further, a movement sequence of the X-ray detection system 16 is defined.
The movement control device 15 controls the movement mechanism 14 to keep the X-ray detection system 16 stationary at each of the two predetermined positions during the X-ray imaging, and
The X-ray grid is moved between two X-ray pulses while keeping the X-ray grid parallel to the grid surface. As a result, two X-rays can be subsequently performed at the two positions.

The high voltage generator 2 generates a voltage and a current in accordance with an imaging sequence, and generates an X-ray with the X-ray tube 3. The X-ray filter 4 absorbs low-energy X-rays, reduces the exposure dose, reduces scattered radiation, and improves image contrast. The X-rays transmitted through the subject 17 enter the X-ray image intensifier 7 after the scattered rays are shielded and attenuated by the X-ray grid 6. The input field of view of the X-ray image intensifier covers the area of one lung and the mediastinum. The X-ray image projected on the input fluorescent screen 18 of the X-ray image intensifier is converted into a visible light image on the output fluorescent screen 19 by the action of the X-ray image intensifier 7. The optical lens system 8 forms this visible light image on the television camera 10. TV camera 10
Converts an image into a video signal and converts the image into a video signal.
Enter 1

[0010] The image acquisition and processing device 11 A / D converts the input video signal, stores it in an internal frame memory, and performs X-ray conversion on the obtained two digital X-ray images.
The geometrical distortion of the image and the shading of the density level of the image by the line detection system are corrected, and the two images are combined so that the subject portion commonly included in the two images coincides, and image processing is performed. To display the image on the image display device 12 and store the image in the recording device 13. Note that the image display device 12 has a function of displaying a one-lung image and a composite image, and can also observe left and right one-lung images side by side. FIG. 1 is an example of a time chart of the X-ray imaging apparatus according to the embodiment. The operation mode of the television camera is a 2,100 line scan mode of 3.75 frames per second, and one frame time is 267 ms. R-wave detector 32
Thus, an electrocardiogram synchronizing signal is extracted from the electrocardiogram waveform measured by the electrocardiograph 31.

As a method of extracting an electrocardiogram synchronizing signal from an electrocardiogram waveform measured by the electrocardiograph 31, for example, as described in Japanese Patent Publication No. A method such as detecting a spike-shaped R wave having a large amplitude indicating the start time of contraction of the heart, and generating a pulse of an electrocardiographic synchronization signal at a time point shifted by a predetermined time (t in FIG. 1) from the timing pulse of the R wave. Can be considered. As a technique for obtaining this timing pulse, an established technique can be used. In FIG. 1, the value of t is set to 300 ms as a typical example so that an electrocardiogram synchronizing signal corresponding to the end-systole of the heart in which the speed of movement of the heart is minimum and the volume of the heart is minimum is generated. It shows the case where it is done. t
Can be set to an appropriate value based on the result of observation of the heart rate and electrocardiographic waveform of the subject.

The position of the detection system is set to the position A in advance, and the photographing preparation completion signal is turned on when the photographing preparation is completed.
When the imaging start command is received, the imaging preparation completion signal is turned off, the readout scan of the television camera is stopped in the immediately subsequent frame, and the pulse X for the first imaging is turned on when the electrocardiogram synchronization signal is first turned on. The X-ray image is accumulated on an imaging surface by irradiating a ray. The first captured image data is read out in the frame next to the X-ray irradiation, and is stored in the image collection / processing device as the first image data. The position of the detection system is moved to the position B in the next frame after the reading is completed. The example shows a case where three frames are required for movement. The reading scan is stopped again in the next frame after the movement is completed, and thereafter, when the electrocardiogram synchronization signal is first turned on, the pulse X-ray for the second imaging is irradiated, and the X-ray image is formed on the imaging surface. To accumulate.

The time required to attenuate the predetermined microphonic noise of the image pickup tube (c in FIG. 1, 1000 m)
s), if the pulse X-ray irradiation for the second imaging is performed earlier, during a frame in which the time from the end of the movement to the end of the frame is longer. The read scanning stop state is continued. FIG. 1 shows a case in such a state. In the next frame, the second
The captured image data is read out and stored in the image collection / processing device as the second image data. The position of the detection system is moved to the position A in the next frame after the reading is completed, and at the time when a predetermined time c required for attenuating the microphonic noise of the image pickup tube has elapsed since the completion of the movement. The photographing preparation completion signal is turned on again. Note that the frame that moves the X-ray slit that controls the X-ray emission range is the same as the frame that moves the X-ray detection system. A typical example of the width of the X-ray pulse is 30 ms.

In the above-described embodiment, an X-ray image intensifier, a television camera, and an X-ray television camera including an optical system for combining the X-ray image intensifier and the television camera are used as the X-ray detection system. Thereby, X-ray fluoroscopy is possible, and positioning of imaging can be easily performed. Further, since the image can be read out in real time, after the X-ray detection system moves to the imaging position, the next imaging can be performed within a short time, and continuous imaging is also possible. The method using an image pickup tube as the imaging element is the most advanced and widespread method for real-time X-ray imaging, and it is possible to use an ultra-high-definition camera with more than 2,000 scanning lines. Yes, high resolution X
There is a feature that a line image can be obtained relatively easily.

As another embodiment, a television camera using a CCD element as an image pickup element can be cited. In the imaging tube used in the above-described embodiment, when the detection system is moved,
Microphonic noise may be mixed in the read image due to the vibration of the structure inside the image pickup tube due to mechanical vibration.However, the CCD device is a solid-state device and does not generate noise due to vibration. The reading and the movement of the detection system can be performed at the same time, and as a result, the photographing interval can be shortened. The present invention is not limited to the above embodiment, but can be modified and implemented as in the following examples.

For example, the digital X-ray imaging apparatus according to the present invention is applicable to many applications possible with the conventional X-ray imaging apparatus, and expands the applicable range. Specifically, images such as tomographic imaging, enlarged imaging, and stereo imaging can be extended to a larger field of view and higher definition than before. In addition, the number of times of shooting is not limited to two, and the method is more generally effective for a plurality of shootings. Further, the field of application of the present invention is not limited to digital X-ray imaging, but is effective for all imaging in which an image is affected by a subject being changed by a heartbeat.

[0017]

As described above in detail, according to the present invention, it is possible to avoid the deformation of the heart in a plurality of images, to eliminate discontinuities at the joints, and to accurately join the images. This has a remarkable effect that it is possible to realize an X-ray imaging apparatus capable of imaging a chest in a range wider than the visual field of the X-ray detection system with high spatial resolution. More specifically, in the DR for the chest, two imagings are performed in the same phase state of the electrocardiographic signal, and the images are accurately joined, so that a range wider than the field of view of the X-ray detection system is obtained. The effect that it becomes possible to realize an X-ray imaging apparatus capable of performing X-ray imaging of a part with high spatial resolution is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an imaging sequence and a movement sequence of a digital X-ray imaging apparatus according to an embodiment of the present invention.

FIG. 2 is a side view showing a schematic configuration of a digital X-ray imaging apparatus according to the embodiment.

FIG. 3 is a top view of the digital radiography apparatus shown in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Imaging | photography control apparatus 2 High voltage generator 3 X-ray tube 4 X-ray filter 5 X-ray slit 5-1 Slit which limits the X-ray emission range in the horizontal direction 6 X-ray grid 7 X-ray image intensifier 8 Optical lens system Reference Signs List 9 optical aperture 10 television camera 11 image collection / processing device 12 image display device 13 recording device 14 moving mechanism 15 movement control device 16 X-ray detection system 17 subject 18 input fluorescent screen 19 output fluorescent screen 20 high-resolution imaging tube 21 X-ray Shielding plate 31 Electrocardiograph 32 R wave detector

──────────────────────────────────────────────────続 き Continuing from the front page (72) Keiji Umeya, Inventor Keiji Umeya 1-280, Higashi Koikekubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory of Hitachi, Ltd. (56) References JP-A-5-212019 (JP, A) JP-A-3-251233 (JP, A) JP-A-4-215743 (JP, A) JP-A-59-231985 (JP, A A) JP-A-61-115539 (JP, A) JP-A-61-143384 (JP, U) JP-B2-34439 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) A61B 6/00

Claims (1)

(57) [Claims] An X-ray tube, an X-ray detection system for detecting X-rays passing through a subject, a moving mechanism for moving the X-ray detection system, and collecting output signals of the X-ray detection system A signal processing device for performing an operation to obtain an image of the subject, a display device for displaying the image, an electrocardiograph, one lung and a mediastinum of the subject, and a field of view of the X-ray detection system. A first radiographing operation performed by moving the X-ray detection system and a second radiography operation performed by moving the other lung and the mediastinum into the field of view of the X-ray detection system. possess a photographing control unit that performs a predetermined same phase state of the output signal of said X-ray detection system X-ray image
A lighting intensifier, a television camera,
Predetermined electron beam read-out scanning of TV camera tube
Obtained by the second shooting after stopping for the time
An X-ray imaging apparatus for reading an image .