JPH0970401A - Radiographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable radioscopy and spot photographing, to attain miniaturization and to improve reliability. SOLUTION: A radiation generation means 32 is installed above a base 31 for laying a testee body B and a first control means 33 for controlling a cone beam R7 from the generation means 32 to the cone beam R8 and a second control means 34 for collimating the cone beam R8 to a fan beam R9 are arranged between the generation means 32 and the testee body B. The first control means 33 irradiates the optional range of a detection means 36 with the cone beam R8 and the second control means 34 is made freely insertable and detachable to/from a radiation route, is made freely movable in a direction vertical to the spreading direction of the fan beam R9 and irradiates the optional range of the detection means 36 with the fan beam R9. A scattering radiation elimination means 35 and the radiation detection means 36 composed of two- dimensionally arrayed radiation conversion elements are successively arranged in the inside of the base 31 and the elimination means 35 is made freely insertable and detachable to/from the route.

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 used for contrast imaging of the stomach, chest, etc. during medical diagnosis.

[0002]

2. Description of the Related Art Conventionally, a film and an intensifying screen are used in combination when performing spot imaging in a radiation imaging apparatus. When radiation such as X-rays passes through the subject and enters the intensifying screen, the phosphor contained in the intensifying screen absorbs radiation energy and emits fluorescence. The fluorescent light sensitizes the film to form a radiation image, and the radiation image is visualized by developing and fixing the film.

In recent years, a radiation imaging apparatus for capturing a radiation image as a digital signal has been developed. This type of radiation imaging apparatus uses a detection means provided with a solid-state conversion element that converts radiation into an electric signal corresponding to its intensity and outputs the electric signal, or absorbs radiation energy and responds to the intensity. There is used a detection unit including a fluorescent substance that emits fluorescence and a solid-state conversion element that converts visible light into an electric signal according to its intensity and outputs the electric signal. In any of the detecting means, the detected electric signal is converted into a digital signal by A / D conversion.

For example, the radiation imaging apparatus is constructed as shown in FIG. 3, and the radiation cone beam R1 emitted from the radiation generating means 1 is made into a cone beam R2 whose irradiation range is regulated by the irradiation field diaphragm 2 and the object to be inspected. Irradiate B. The cone beam R2 that irradiates the subject B is absorbed and scattered by the subject B, transmitted through the subject B, and transmitted radiation that carries the information of the radiation image, and the cone beam R2 that is scattered by the subject B and shows the sharpness of the radiation image. The scattered radiation is impaired and enters the detection means 3.

Here, since the transmitted radiation and the scattered radiation are incident on the detection means 3 in a mixed state, these radiations reduce the sharpness of the radiation image. Therefore, the grid 4 is arranged in front of the detecting means 3 so that scattered radiation is removed by the grid 4.
The grid 4 is often made of a substance having a high radiation absorptivity and a substance having a low radiation absorptivity bonded in a parallel lattice pattern.

On the other hand, a slit scan mechanism may be incorporated to remove scattered radiation. This radiation imaging apparatus is configured as shown in FIG.
The cone beam R3 emitted from the subject is viewed by the collimator 12 as a fan beam R4 that spreads in one direction, and the subject B
Is irradiated. The fan beam R4 that has passed through the subject B is converted into an electric signal by the line sensor, that is, the detection means 13, in which the radiation detection elements are linearly arranged. The fan beam R4 is scanned on a desired imaging region of the subject B, and the electric signal output from the detection unit 13 is visualized through a signal processing unit, an image processing unit, an image display unit, and the like (not shown).

In the radiation imaging apparatus equipped with this slit scanning mechanism, the fan beam R4 is applied to the subject B, so that the ratio of scattered radiation to transmitted radiation can be reduced, and the grid 4 shown in FIG. 3 is used. Without doing so, it is possible to obtain a radiation image with a higher sharpness. In order to scan the fan beam R4, a table (not shown) on which the subject B is placed is moved, or both the generating means 11 and the detecting means 13 are moved so that their relative positions do not change. There is.

FIG. 5 shows a radiation T used for contrast imaging of the stomach.
It is a block diagram of V apparatus. In this radiation TV apparatus, a moving image can be obtained by fluoroscopy and a still image can be obtained by spot radiography, and the spot radiography is performed after the positioning of the contrast radiography is performed by fluoroscopy. It has become.

That is, upon fluoroscopy, the subject B is laid on the table 21 and a fluoroscopy switch (not shown) is turned on. The cone beam R5 emitted from the generating means 22 is a cone beam whose irradiation range is regulated by the irradiation field diaphragm 23.
The subject B is irradiated with R6. The cone beam R6 that irradiates the subject B has scattered radiation removed by the grid 24, and then enters the image intensifier 25 to be converted into light. This light enters the image pickup means 26 through photoelectron acceleration and image reduction, is converted into a TV image, and then is displayed as a perspective image on an image display means (not shown).

In the spot photographing, the photographing position is determined while observing the perspective image displayed on the image display means. When the spot photographing switch is turned on, the film F is pulled out from the replenishing magazine 27, sandwiched between the intensifying screens 28, and inserted between the grid 24 and the image intensifier 25. After that, the cone beam R6 by a single pulse irradiates the subject B, a radiation image is photographed on the film F, and the photographed film F is collected in the collecting magazine 29.

[0011]

However, in the above-mentioned radiation TV apparatus, fluoroscopic means such as the image intensifier 25, the image pickup means 26, and the image display means are required for the fluoroscopy, and the spot radiography is required. Spot photographing means such as the film F, the replenishing magazine 27, the intensifying screen 28, and the collecting magazine 29 are required. Therefore, there is a problem that the conventional radiation TV apparatus becomes large in size.

Further, in order to perform spot imaging with high sharpness in the radiation TV apparatus, it is necessary to incorporate a slit scan mechanism. In this case, in order to scan the fan beam, the table 21 on which the subject B is laid down is moved, or both the generating means 22 and the image intensifier 25 are moved so that their relative positions do not change. There must be. For this reason, it is expected that there will be a problem that the device becomes large-sized, the movable part becomes complicated, and the vibrating part also increases, which makes it difficult to mount the device on a vehicle for use.

The object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a small-sized radiation imaging apparatus capable of performing fluoroscopy and performing spot imaging with high sharpness and having little vibration.

[0014]

A radiation imaging apparatus according to the present invention for achieving the above object is a radiation imaging apparatus for detecting radiation emitted from a radiation generating means and irradiating an object with a detecting means, wherein The radiation path between the means and the object is provided with a first regulating means for making the radiation into a cone beam and irradiating it in an arbitrary range, and a second regulating means for making the radiation into a fan beam and irradiating it in an arbitrary area. It is characterized by that.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a configuration diagram of an embodiment in a state of performing contrast imaging of a stomach, and a radiation generating means 32 for generating a radiation cone beam R7 is installed above a table 31 on which the subject B is laid down. In the radiation path between the generating means 32 and the subject B, a first restricting means 33 for restricting the cone beam R7 to the cone beam R8 and a second restricting means 34 for collimating the cone beam R8 to the fan beam R9. And are sequentially installed, and the second restricting means 34 can be inserted into and removed from the radiation path.

Further, inside the table 31, the removing means 35 for removing the scattered radiation scattered by the subject B and the detecting means 3 for detecting the transmitted radiation passing through the subject B.
6 are sequentially arranged, and the removing means 35 can be inserted into and removed from the radiation path. Further, not-shown signal processing means, image processing means, and image display means for visualizing the signal detected by the detection means 36 are provided, and not-shown control means for controlling each of the above-mentioned means are provided. .

Here, the first restricting means 33 is an irradiation field diaphragm, which arbitrarily restricts the irradiation range of the cone beam R7 from the generating means 32, and detects the restricted cone beam R8.
Irradiation is performed in an arbitrary range of 6. Also,
The second restricting means 34 is provided with plural kinds of slits having different opening shapes, and by selecting an arbitrary slit, the irradiation range of the cone beam R8 is restricted to plural kinds, and the restricted fan beam R9 is detected. It is designed to irradiate an arbitrary range of 36. The slit is movable in a direction perpendicular to the direction in which the fan beam R9 spreads so that the fan beam R9 can scan an arbitrary range of the subject B. The irradiation ranges of the first restricting means 33 and the second restricting means 34 are set in consideration of the imaged site, scanning time, and the like.

Further, the second restricting means 34 and the removing means 35.
The position of is controlled by the control means as follows. That is, the second restricting means 34 is used when seeing through.
Is located outside the radiation path as shown by the dotted line, and the removing means 3
5 is located in the radiation path as shown by the dotted line. on the other hand,
During spot imaging, the second restricting means 34 is located inside the radiation path as shown by the solid line, and the removing means 35 is located outside the radiation path as shown by the solid line.

The detection means 36 is a combination of a scintillator that absorbs radiation and emits visible light corresponding to the energy thereof, and a solid-state photodetector in which photoelectric conversion elements that convert visible light into electric signals are two-dimensionally arranged. A solid-state radiation detector in which two-dimensionally arranged radiation conversion elements for converting radiation into electric signals is used. For example, as shown in FIG. 2, a large number of radiation conversion elements 41 are two-dimensionally arranged in the detection means 36, and the electric charges accumulated in each conversion element 41 are switched when being sent to the output terminal 42. Transfer units 43 composed of TFTs are provided, and these transfer units 43 are sequentially switched from the uppermost row to the lowermost row by the transfer pulse 44 provided for each column.

In the detecting means 36, the image signal is continuously read when the radiation is continuously irradiated. Further, when the radiation is intermittently irradiated, the radiation pulse is irradiated, and after a certain time has elapsed, the image signals in the uppermost row to the lowermost row are sequentially read, and then the next radiation pulse is irradiated. It has become so. Then, the irradiation of the radiation pulse and the reading of the image signal are synchronized, and the reading of the image signal is performed every few seconds.
It is performed for several tens of frames, and after the image signal is processed by the signal processing means and the image processing means, it is displayed as a visualized radiation image on the image display means.

When performing contrast imaging of the stomach with the above-described radiation imaging apparatus, the apparatus is adjusted while observing the imaging site, timing, and the state of adhesion of the contrast agent to the gastric mucosa, and then spot imaging is performed. To do. During fluoroscopy, the second restricting means 34 is located outside the radiation path as shown by the dotted line, and the removing means 35 is located inside the radiation path as shown by the dotted line. When the optimum irradiation range is selected by the first restricting means 33 and the fluoroscopic switch is continuously pressed, the generating means 32 is generated.
The cone beam R7 emitted from is a cone beam R8 whose irradiation range is optimally regulated by the first regulating means 33, and irradiates the subject B. The cone beam R8 is absorbed by the subject B with different absorptances depending on the constituent elements of the subject B, the scattered radiation scattered by the subject B is removed by the removing means 35, and the cone beam R8 is transmitted through the subject B. The radiation is detected by the detecting means 3 as information on the subject B according to its intensity.
It is incident on 6.

Cone beam R8 incident on the detecting means 36
Supplies the information of the subject B to the detection means 36 by one irradiation. At this time, charges corresponding to the intensity of the cone beam R8 are generated in the conversion element 41 and accumulated inside the conversion element 41. Next, the transfer pulse 44 is sent to the transfer unit 43 in the uppermost row, and the switch of the transfer unit 43 in the same row is closed. As a result, the charges accumulated in the conversion element 41 are transferred to the output terminal 42 through the TFT, which is the transfer unit 43, and the image signal in the uppermost row is read out.

Similarly, the transfer pulse 44 is sequentially sent from the second row to the bottom row, and the image signal on the entire surface of the detecting means 36 is read out. That is, one radiation image is formed by performing signal accumulation / readout once for each pixel. This image signal is displayed as a visualized perspective image on the image display means through the signal processing means and the image processing means. It is possible to see through even when the removing means 35 is located outside the radiation path, but at this time, the sharpness of the see-through image is lowered.

On the other hand, spot photography is performed by the second regulation means 34.
Select the slit with the optimum aperture shape and perform slit scanning with the fan beam R9. At this time, the slit is located inside the radiation path, and the removing means 35 is located outside the radiation path. When a spot photographing switch (not shown) is pressed in this state, the fan beam R9 whose irradiation range is regulated by the second regulating means 34 illuminates the subject B and enters the detecting means 36. Then, the slit is moved in a direction perpendicular to the direction in which the fan beam R9 spreads, and the fan beam R9 is scanned over the entire imaging region of the subject B. In order to scan the fan beam R9,
The generating means 32, the first restricting means 33, and the second restricting means 34 may be integrated and moved in parallel with the detecting means 36.

The scanning of the fan beam R9 is performed in synchronization with the selection of the conversion element 41 from which the signal is read. Subject B
The main axis of the fan beam R9 transmitted through
When it is above 1, the electric charge according to the intensity of the fan beam R9 is generated in the conversion element 41 in the uppermost row, and is accumulated inside the conversion element 41. After that, the transfer pulse 44 is sent to the transfer unit 43 in the uppermost row, and the switch of each transfer unit 43 in the same row is closed. As a result, the charges accumulated in the conversion elements 41 in the top row are transferred to the output terminal 42 through the transfer section 43, and the image signals in the top row are read out. Next, the second restricting means 34 moves so that the main axis of the fan beam R9 moves above the conversion element 41 in the second row, the same processing as described above is performed, and the image signal in the second row is read out.

In this way, the main axis of the fan beam R9 is sequentially scanned from the top row to the bottom row, and the image signal for one image is read out. That is, one radiation image is formed by accumulating / reading out signals for each pixel a plurality of times. Then, this image signal is displayed as a visualized radiation image on the image display means through the signal processing means and the image processing means.

Here, when the transmitted radiation is incident on the conversion element 41 of a certain column, the scattered radiation may be incident on the conversion element 41 of another column. However, after the effective charge generated by the transmitted radiation is read out, the charge generated by the scattered radiation is sent to the output terminals 42 all at once, and the output from the output terminal 42 is prevented from being read out, thereby removing the scattered radiation. be able to. Note that spot photography can also be performed by the cone beam R8 in the perspective state, but in this case, the sharpness of the spot image is reduced.

In the embodiment described above, the first restricting means 33
The irradiation range of the cone beam R8 is arbitrarily controlled by the second control means 34, and the second restriction means 34 is removably provided in the radiation path to arbitrarily control the irradiation range of the fan beam R9. Thus, both fluoroscopy and spot imaging of the subject B can be performed. Therefore, it is possible to omit the conventionally required image intensifier 25 for fluoroscopy, the image pickup means 26, etc., as shown in FIG. Since the collecting magazine 29 and the like can be omitted, the size, the simplification, and the price can be reduced.

Further, since the irradiation range of the fan beam R9 can be restricted to an arbitrary range by the second restricting means 34 and the slit scan can be performed, the sharpness of the spot image can be improved. At the same time, it is possible to eliminate the need to move the conventional generating means 11 and detecting means 13 as shown in FIG. Therefore, since the number of movable parts can be reduced, the number of vibrating parts can also be reduced, and reliability can be improved. For example, it can be mounted on a vehicle and used.

Although the above-described embodiment has been described as being applied to the imaging of the contrast of the stomach, it can be similarly applied to the imaging of the chest. The second restricting means 34 is the first restricting means 33.
However, it is also possible to arrange between the generating means 32 and the first regulating means 33. And
Although the second restricting means 34 regulates the fan beam R9 so as to irradiate the conversion element 41 in one row, it may be regulated so as to irradiate in two or more rows by changing the opening shape of the slit. In the case of irradiating two rows, the data reading is performed in the order of the data reading of the first row and the data reading of the second row, and then the fan beam is scanned to the next irradiation area.

[0031]

As described above, in the radiation imaging apparatus according to the present invention, the irradiation range of the cone beam can be arbitrarily controlled by the first restricting means, and the irradiation range of the fan beam can be arbitrarily controlled by the second restricting means. Therefore, it is possible to perform fluoroscopy and spot imaging with high sharpness with low exposure.
Moreover, since it is not necessary to move the first restricting means and the detecting means, it is possible to reduce the size, simplify, and reduce the price. Furthermore, since the number of movable parts can be reduced, it is possible to reduce the occurrence of vibration and improve the reliability.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is a block diagram of detection means.

FIG. 3 is a configuration diagram of a conventional example.

FIG. 4 is a configuration diagram of a conventional slit scan.

FIG. 5 is a configuration diagram of a conventional radiation TV apparatus.

[Explanation of symbols]

 32 generating means 33 first restricting means 34 second restricting means 35 removing means 36 detecting means 41 conversion element 42 output terminal 43 transfer section 44 transfer pulse B subject R8 cone beam R9 fan beam

Claims (7)

[Claims] 1. A radiation imaging apparatus for detecting radiation emitted from a radiation generating means and irradiating an object with a detecting means, in a radiation path between the generating means and the object, the radiation is a cone beam and has an arbitrary range. To irradiate the first
And a second restricting means for irradiating an arbitrary range with radiation as a fan beam. 2. The radiation imaging apparatus according to claim 1, wherein a removing unit for removing the radiation scattered by the object is provided in the radiation path so as to be freely inserted and removed. 3. The first restriction means irradiates the radiation to an arbitrary range within substantially the entire surface of the detection means.
A radiation imaging apparatus according to claim 1. 4. The radiation imaging apparatus according to claim 1, wherein the second restricting unit is provided so as to be freely inserted into and removed from the radiation path. 5. The radiation imaging apparatus according to claim 1, wherein the second restricting unit includes a plurality of types of slits having different opening shapes. 6. The radiation imaging apparatus according to claim 5, wherein the detection means is caused to scan the radiation by moving the slit. 7. When the second regulating means is outside the radiation path, one radiation image is formed by accumulating / reading out a signal once for each pixel of the two-dimensional array of the detecting means, and The radiation imaging apparatus according to claim 4, wherein when the second restricting unit is in the radiation path, one radiation image is formed by accumulating / reading out signals for each pixel a plurality of times.