JP5448316B2 - Radiography equipment - Google Patents

Description

  The present invention relates to a radiation imaging apparatus capable of imaging in a plurality of imaging modes.

  Conventionally, a subject as a subject is placed between an imaging system consisting of a radiation source and a radiation detector arranged opposite to each other, and the subject is examined with an axis substantially parallel to the body axis of the subject as the center of rotation. There is known a radiation imaging apparatus that performs imaging while rotating a person. As an example of such an imaging apparatus, imaging is performed by rotating the subject while standing or sitting, and the acquired radiation projection image data is reconstructed to obtain a tomographic image.

  Patent Document 1 discloses a photographing apparatus that can also be used for still image photographing in a standing position or a sitting position by an easier operation. Patent Document 2 discloses an imaging apparatus capable of performing CT imaging using a C-arm type radiography apparatus.

JP 2005-205082 A JP-A-11-221206

  However, the conventional radiographic apparatus has the following problems, for example. A CT imaging mode in which a subject is rotated to perform imaging, and the obtained radiation projection image data is reconstructed to generate a tomographic image; and a still image imaging mode in which the subject is stationary to obtain a still image imaging; In this imaging, the imaging distance between the radiation source and the radiation detector may be different from each other.

  In such a case, parameters such as a radiation irradiation method of radiation and an acquisition method of image data by a radiation detector are set according to a desired imaging mode, and the radiation source is moved to a predetermined position. The shooting distance is set. However, if the shooting parameters and shooting distance are set independently, there is a risk that shooting will be performed with the shooting parameters or shooting distance set incorrectly.

  An object of the present invention is a radiography that solves the above-described problems, enables imaging in a plurality of imaging modes, improves operability, reduces erroneous operations, and prevents imaging using imaging parameters that do not match the imaging purpose. To provide an apparatus.

A radiation imaging apparatus according to an embodiment of the present invention acquires radiation image data by detecting radiation emitted from a radiation source with a radiation detector based on at least one imaging parameter corresponding to a plurality of imaging modes. A radiation imaging apparatus capable of detecting a radiation detector, detection means for detecting information indicating a positional relationship between the radiation source and the radiation detector, and the radiation detector based on the information indicating the positional relationship. Determining means for determining parameters relating to imaging, and control means for controlling a radiation detector based on the determined parameters, wherein the determining means determines the imaging mode of the radiation imaging apparatus based on the positional relationship. based on the information indicating the radiation while moving the object, the radiation source, or at least one of the radiation detector A first imaging mode for reconstructing the radiation image data acquired in the detector to generate an image, and acquiring the radiation image data by the radiation detector without moving the radiation source and the radiation detector. And determining a parameter related to the shooting associated with the determined shooting mode.

  According to the radiation imaging apparatus of the present invention, it is possible to acquire radiographic image data of a subject in a plurality of imaging modes, realize reduction of erroneous operations, and prevent imaging using imaging parameters that do not match the imaging purpose. Can do.

  The present invention will be described in detail based on the embodiments shown in the drawings.

  FIG. 1 is a configuration diagram of a radiation imaging apparatus that performs imaging while rotating a subject as a subject in the first embodiment. A turntable 2 is disposed on the turntable 1, and a drive unit 3 for driving the turntable 2 is provided on the lower surface of the turntable 1, and the turntable 2 is configured to be rotatable about a rotation axis O. . The turntable 1 is provided with a detection mechanism (not shown) that detects the angular position and rotation speed of the turntable 2.

  On the turntable 2, a chair 4 for supporting the buttocks of the subject S and a backrest unit 5 for supporting the trunk and head of the subject S are provided. In addition, a grip 5b for the subject S to grip is provided at the upper end of the back rest portion 5a of the back rest unit 5.

  The backrest portion 5a is divided into upper and lower parts by a rotating shaft 5c arranged at substantially the same height as the seat surface portion 4a of the chair 4, and the backrest portion 5a can be tilted to the rear side of the chair 4 with the rotating shaft 5c as a rotation center. It is possible. The site | part arrange | positioned in the area | region where a radiation is irradiated among the back support parts 5a is comprised with the material with favorable radiation transmittance.

  A radiation source 7 composed of an X-ray tube movable along a rail 6 provided on the floor of the photographing room is disposed behind the back support unit 5. In front of the back support unit 5, a radiation detector 8 that has two-dimensionally arranged light detection elements and detects radiation that is X-rays is disposed opposite to the radiation source 7. The distance from the radiation detector 8 can be changed. The radiation detector 8 includes a well-known phosphor, a light detection element, an electric circuit, a housing, and the like, and is configured to detect radiation image data by radiation that has passed through the subject S. The rail 6 has a built-in linear encoder 9 for detecting the movement position of the radiation source 7.

  The radiation detector 8 is connected to a data collection unit 10 for storing the acquired radiation projection image data. Further, a display unit 12 for displaying the arithmetically processed image is connected to the data collecting unit 10 through a reconstruction unit 11 that performs arithmetic processing on the stored image data.

  In addition, a system control unit 13 that centrally controls the entire imaging apparatus is provided, and is electrically connected to the turntable 1, the drive unit 3, the rail 6, the radiation source 7, the radiation detector 8, the data collection unit 10, and the reconstruction unit 11. It is connected. Further, an input unit 14 is connected to the system control unit 13 in order to instruct setting of shooting conditions such as a shooting mode and start of shooting.

  FIG. 2 shows a circuit configuration diagram of the radiation detector 8. When the radiation emitted from the radiation source 7 passes through the subject S and enters the radiation detector 8, a phosphor (not shown) stacked on the radiation detector 8 converts the radiation into visible light corresponding to the intensity. . Then, charges corresponding to the intensity of the visible light are generated in the individual photodetecting elements 8a arranged in a two-dimensional manner. This electric charge is accumulated in the accumulation part inside the photodetecting element 8a, and the radiation image information of the subject S is converted into a two-dimensional charge distribution.

  Subsequently, a transfer pulse P is sent to the transfer unit 8b provided in each photodetecting element 8a in the top row, and a switch signal is input to a TFT (thin-film transistor) of the transfer unit 8b. At this time, the electric charge accumulated in the light detection element 8a is transferred to the switch 8d of the multiplexer 8c via the transfer unit 8b, and the switches are connected one by one in the order of 8d1, 8d2,. As a result, the electric charge is finally transferred sequentially to the signal output terminal 8e, and reading of the image signal for one line of the uppermost column is completed. In this way, the transfer pulse P is sent sequentially from the top row to the bottom row, and in synchronization with this transfer pulse P, the switches 8d of the multiplexer 8c are sequentially connected from left to right. As a result, the charges accumulated in all the light detection elements 8a configured in the radiation detector 8 are read out as one image signal. The read image signal is converted into digital data through an amplifier, an A / D converter, etc. (not shown), and a collection of all the digital data becomes one radiation image data.

  FIG. 3 is a plan view of the radiation source 7 and the radiation detector 8 as viewed from above the imaging system. The width dimension of the radiation detector 8 is W. With respect to the mutual arrangement of the radiation source 7, the radiation detector 8, and the rotation axis O of the turntable 2, the distance between the radiation detector 8 and the rotation axis O is M. And the rotation axis O are arranged so that the distance is L.

  In the first embodiment, since the relative position between the radiation detector 8 and the turntable 1 is fixed, the distance M is a constant value, and the radiation source 7 is movable via the rail 6, so the distance L Is a fluctuating value. Then, a diameter D of a circle of a chain line inscribed in two line segments respectively connecting the both ends of the effective imaging region of the radiation detector 8 and the radiation source 7 and having the rotation axis O as the center can be generated at the time of CT imaging. This is the maximum area on the plane of the tomographic image.

  FIG. 4 shows a flowchart of the CT imaging process. First, when the CT imaging process is started, the process proceeds to step S <b> 1, the subject S is seated on the seat surface portion 4 a of the chair 4, and the trunk and head are brought into close contact with the backrest portion 5 a of the backrest unit 5. Then, the subject S is placed at a predetermined position on the turntable 2 by extending both arms of the subject S toward the ceiling and gripping the grip 5b.

  Next, in step S2, the radiation source 7 is moved to a predetermined position along the rail 6 so that the radiation source 7 and the radiation detector 8 have a desired imaging distance at the time of CT imaging. Subsequently, in step S <b> 3, the position information of the radiation source 7 detected by the linear encoder 9 provided on the rail 6 is transmitted to the system control unit 13.

  In FIG. 3, for example, when the width dimension W is 500 mm and the distance M is 400 mm, the radiation source 7 is arranged so that the distance L is 3000 mm. Then, the diameter D of the maximum region on the plane of the tomographic image that can be generated during CT imaging is about 440 mm, and CT imaging of the entire chest of the subject S is possible.

  In step S4, the imaging mode is automatically determined based on the correlation table between the position information of the radiation source 7 set and stored in advance in the system control unit 13 and the imaging mode. In this embodiment, the correlation table is set in advance so that the imaging mode is chest CT imaging when the distance L is 3000 mm, that is, the imaging distance (M + L) is 3400 mm. Subsequently, in step S5, an imaging parameter related to chest CT imaging is automatically determined based on a correlation table between imaging modes set and stored in advance in the system control unit 13 and imaging parameters. In step S6, the photographing parameter determined in step S5 is displayed on the input unit 14.

  Next, when the shooting-related parameters displayed on the input unit 14 are confirmed, it is determined in step S7 whether or not a shooting start command has been input from the input unit 14, and if it is determined that a shooting start command has been input, step S8. Proceed to If no shooting start command is input in step S7, step S7 is repeated until the shooting start command is input.

  In step S8, the drive unit 3 starts rotation of the turntable 2. In step S9, it is determined whether or not the turntable 2 has reached a predetermined rotation speed. When the turntable 2 reaches a predetermined speed, the process proceeds to step S10, and radiation is irradiated from the radiation source 7 toward the subject S under predetermined irradiation conditions suitable for chest CT imaging. When it is determined in step S9 that the turntable 2 has not reached the predetermined rotation speed, step S9 is repeated until the turntable 2 reaches the predetermined rotation speed.

  Subsequently, imaging of the subject S is started in step S11, and the radiographic image data of the chest of the subject S arranged in the radiation irradiation region is obtained at every predetermined rotation angle of the turntable 2 by the radiation detector 8. A predetermined number is acquired. Then, after imaging of the subject S is started, imaging for one scan is completed by rotating 360 °, and it is determined in step S12 whether imaging is completed. When it is determined that the imaging has been completed, the acquisition of the radiation image data by the radiation detector 8 is stopped, the process proceeds to step S13, and at the same time the irradiation of radiation from the radiation source 7 is stopped, the driving unit 3 The rotation of the turntable 2 is decelerated and stopped. If it is determined in step S12 that imaging has not yet been completed, the process returns to step S11 and the acquisition of radiation image data is continued.

  On the other hand, the plurality of radiographic image data acquired for each predetermined angle of the turntable 2 in step S11 proceeds to step S14, and is sequentially transmitted and stored in the data collection unit 10. In step S15, the reconstruction unit 11 performs a reconstruction process of the radiation image data and generates a predetermined tomographic image. Then, in step S16, the tomographic image is displayed on the display unit 12 and the process ends.

  Here, one piece of radiation image data acquired by the radiation detector 8 is read by adding the charges accumulated in the 4 × 4 (= 16) light detection elements 8a adjacent to each other as one image signal. To be controlled. That is, the transfer pulse P is simultaneously sent to the transfer units 8b of the four photodetection elements 8a adjacent to each other among the photodetection elements 8a arranged in a two-dimensional manner described in FIG. A switch signal is input to the TFT. Then, the image signals of the four pixels adjacent in the vertical direction are simultaneously transferred to the multiplexer switch 8d.

  When the four adjacent switches 8d are connected at the same time, the charges accumulated in the sixteen adjacent photodetectors 8a can be read out simultaneously. By sequentially repeating the simultaneous connection of the four switches of the adjacent multiplexers from the left to the right, the readout of the image signals for the four uppermost columns is completed for every 16 photodetecting elements. By sequentially repeating this operation from the top row to the bottom row, the charges accumulated in the 16 adjacent photodetectors 8a are read out as one image signal.

  Therefore, the number of digital data composing one piece of radiation image data acquired by the radiation detector 8 is 1/16 of the total number of the light detection elements 8a. Accordingly, it is possible to reduce the transmission time of all digital data to the data collection unit 10, the memory capacity at the time of storage, and the reconstruction processing time when the reconstruction unit 11 generates a tomographic image.

  FIG. 5 is a flowchart of the still image shooting process. First, when the still image shooting process is started, the process proceeds to step S21, and as shown by the chain line in FIG. 1, the upper portion of the backrest portion 5a is tilted to the opposite side of the chair 4 with the rotation shaft 5c as the rotation center, The backrest 5a is retracted from the radiation irradiation range. Subsequently, in step S22, the subject S is placed close to the radiation detector 8 in a standing state as indicated by a chain line. Next, in step S23, the radiation source 7 is moved to a predetermined position along the rail 6 so that the radiation source 7 and the radiation detector 8 have a desired shooting distance at the time of still image shooting. In step S <b> 24, the position information of the radiation source 7 detected by the linear encoder 9 provided on the rail 6 is transmitted to the system control unit 13.

  In FIG. 3, for example, when the distance M is 400 mm and the radiation source 7 is arranged so that the distance L is 1400 mm, the imaging distance (M + L) is generally used as the imaging distance at the time of chest still image shooting. 1800 mm.

  Similar to the flowchart shown in FIG. 4, the imaging mode is chest stationary based on the correlation table between the position information or imaging distance information of the radiation source 7 and the imaging mode set and stored in advance in the system control unit 13 in step S25. The image shooting mode is determined. When the shooting mode is determined, in step S26, various parameters relating to chest still image shooting are automatically determined based on the correlation table between the shooting modes set and stored in the system control unit 13 in advance and the parameters related to shooting. The In step S27, the photographing parameters determined in step S26 are displayed on the input unit 14.

  Next, in step S28, it is determined whether an imaging start command has been input. When the shooting-related parameters displayed on the input unit 14 are confirmed and a shooting start command is input from the input unit 14, the process proceeds to step S29, and the operation is performed based on the determined shooting-related parameters. If no shooting start command is input in step S28, step S28 is repeated until the shooting start command is input.

  When an imaging start command is input in step S28, radiation is irradiated from the radiation source 7 toward the subject S under predetermined irradiation conditions suitable for chest still image shooting in step S29. Subsequently, in step S30, imaging of the subject S is started, and radiation image data of the chest of the subject S arranged in the radiation irradiation area is acquired by the radiation detector 8. In step S31, after a predetermined time has elapsed since the start of imaging of the subject S, radiation irradiation is stopped and imaging is completed. When imaging is completed, one piece of radiographic image data acquired in step S32 is transmitted to and stored in the collection unit 10, and then displayed on the display unit 12 as a still image in step S33.

  Here, the charge accumulated in one photodetecting element 8a is controlled to be read out as one image signal, and one radiographic image data acquired by the radiation detector 8 is the same as the total number of photodetecting elements 8a. Composed of digital data.

  In the case of the imaging process in the two types of imaging modes described above, the irradiation conditions of the radiation irradiated from the radiation source 7 such as the tube voltage, the tube current, and the irradiation time of the radiation, and the rotation state of the turntable 2 are different. Further, the number of radiation image data acquired by the radiation detector 8 and the number of data additions for determining the number of digital data constituting one radiation image data are different, and the parameters relating to imaging determined in conjunction with the imaging mode Become.

  In the first embodiment, since the imaging mode and the parameters relating to imaging are automatically switched by setting the imaging distance by moving the radiation source 7, operability can be improved and erroneous operations can be reduced.

  FIG. 6 is a flowchart of the CT imaging process in the second embodiment. The same steps as those in FIG. 4 are denoted by the same steps.

  First, when the CT imaging process in this embodiment is started, a desired imaging mode is selected from a plurality of imaging modes displayed on the input unit 14 in step S31 and directly input from the input unit 14. Next, in step S32, the photographing mode information input in step S31 is transmitted to the system control unit 13.

  In the second embodiment, the imaging mode is input and transmitted as the chest CT imaging mode. When the imaging mode is determined, in step S33, the position information or the imaging distance information of the radiation source 7 is automatically determined based on the correlation table between the imaging mode and the imaging-related parameters set and stored in advance in the system control unit 13. To be determined. Further, when imaging mode information is transmitted to the system control unit 13 in step S32, parameters relating to imaging other than the position information of the radiation source 7 are determined in the same manner as in step S5 of the first embodiment.

  Next, the same processes as steps S1 to S3 of the first embodiment are performed. In the present embodiment, as in the CT imaging process of the first embodiment, the radiation source 7 is arranged so that the imaging distance is 3400 mm. Subsequently, in step S34, it is determined whether or not the position information of the radiation source 7 determined by the system control unit 13 matches the position information of the radiation source 7 transmitted to the system control unit 13 in step S3. To do. If they match, the process proceeds to step S35, the determination result “OK” is displayed on the display unit 12, and the CT imaging process is completed through steps S7 to S16. The determination result and other parameters related to photographing are displayed on the input unit 14. If they do not match in step S34, the process proceeds to step S36, the determination result “NG” is displayed on the display unit 12, the process returns to step S2 again, and the radiation source 7 is moved to the desired position during CT imaging. .

  In the second embodiment, parameters related to shooting other than the shooting distance are automatically determined according to the input shooting mode, but setting of the shooting distance, which is a part of the parameters related to shooting, is performed independently. . However, since it is determined and displayed whether the desired shooting distance corresponding to the input shooting mode is reached, it is possible to reduce erroneous operations.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

1 is a configuration diagram of a radiation imaging apparatus according to Embodiment 1. FIG. It is a circuit block diagram of a radiation detector. It is a top view of arrangement | positioning regarding an imaging | photography system. It is a flowchart figure of CT imaging process. It is a flowchart figure of a still image photographing process. FIG. 6 is a flowchart of a CT imaging process of Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turntable 2 Turntable 3 Drive part 4 Chair 5 Backrest unit 5a Backrest part 5b Grip 5c Rotating shaft 6 Rail 7 Radiation source 8 Radiation detector 9 Linear encoder 10 Data collection part 11 Reconfiguration part 12 Display part 13 System control Part 14 Input part S Subject

Claims (12)

A radiation imaging apparatus capable of acquiring radiation image data by detecting radiation emitted by a radiation source with a radiation detector based on at least one imaging parameter corresponding to a plurality of imaging modes,
A radiation detector;
Detecting means for detecting information indicating a positional relationship between the radiation source and the radiation detector; determining means for determining a parameter relating to the imaging of the radiation detector based on the information indicating the positional relationship;
Control means for controlling the radiation detector based on the determined parameter,
The determination unit acquires the imaging mode of the radiation imaging apparatus in the radiation detector while moving at least one of the subject, the radiation source, and the radiation detector based on the information indicating the positional relationship. A first imaging mode for reconstructing the radiation image data to generate an image; and a second imaging for acquiring the radiation image data by the radiation detector without moving the radiation source and the radiation detector. A radiation imaging apparatus, wherein the parameter relating to the imaging associated with the determined imaging mode is determined. The radiation imaging apparatus according to claim 1, wherein the first imaging mode is an imaging mode that performs tomography, and the second imaging mode is an imaging mode that performs still image shooting. The detection unit detects at least one of position information of the radiation source or distance information between the radiation source and the radiation detector as information indicating the positional relationship. Radiography equipment. A radiation imaging apparatus capable of acquiring radiation image data by detecting radiation emitted by a radiation source with a radiation detector based on at least one imaging parameter corresponding to a plurality of imaging modes,
A radiation detector;
Detecting means for detecting first information indicating a positional relationship between the radiation source and the radiation detector; and determining means for determining a parameter relating to the imaging of the radiation detector based on the information indicating the positional relationship;
Control means for controlling the radiation detector based on the determined parameters;
When the positional relationship between the radiation source and the radiation detector is changed from the positional relationship indicated by the first information, information indicating the changed positional relationship is determined based on the first information. radiographic apparatus characterized by having a a determination means for determining whether or not to correspond to the shooting mode according to the photographing parameters. Display means for displaying a display corresponding to the result of the determination;
The radiation imaging apparatus according to claim 4, further comprising: The radiographic apparatus according to claim 4, wherein the control unit performs control so that imaging according to an imaging start command cannot be performed when it is determined that the determination does not match. The radiation imaging apparatus according to claim 1, wherein the determination unit further determines an irradiation condition of the radiation from the radiation source based on information indicating the positional relationship. The determination means further includes a data addition number for determining the number of the radiation image data acquired by the radiation detector based on the information indicating the positional relationship, or the number of digital data constituting one of the radiation image data. The radiation imaging apparatus according to claim 1, wherein at least one of the two is determined. The determination unit further determines a rotation state of an imaging system including a subject or the radiation source and the radiation detector based on the information indicating the positional relationship. The radiation imaging apparatus described in 1. A radiation imaging apparatus capable of acquiring radiation image data by detecting radiation emitted by a radiation source with a radiation detector based on at least one imaging parameter corresponding to a plurality of imaging modes,
Based on detection means for detecting information indicating the positional relationship between the radiation source and the radiation detector, and information indicating the positional relationship, the imaging mode of the radiation imaging apparatus is set to at least one of a subject and the radiation source. A first imaging mode for generating a tomographic image by reconstructing the radiation image data acquired in the radiation detector while moving; and the radiation image by the radiation detector without rotating the subject and the radiation source. Deciding means for deciding to any one of the second shooting mode for acquiring data, and determining the parameters relating to the shooting corresponding to the shooting mode;
Control means for controlling the radiation detector based on the determined parameters;
A radiation imaging apparatus comprising: A method for controlling a radiographic system having a radiation source and a radiation detector, comprising: detecting information indicating a positional relationship between the radiation source and the radiation detector;
Determining a parameter relating to the imaging of the radiation detector based on information indicating the positional relationship, and a rotation state of at least one of an imaging system including the radiation source and the radiation detector or an object;
And a step of controlling the radiation imaging system based on the determined parameter. A method of controlling a radiographic system having a radiation source and a radiation detector, the step of detecting information indicating a positional relationship between the radiation source and the radiation detector, and the radiation based on the information indicating the positional relationship The imaging mode of the imaging system includes a first imaging mode for reconstructing radiographic image data acquired by the radiation detector while moving at least one of the subject or the radiation source, and generating a tomographic image, the subject and Determining one of the second imaging modes in which radiation image data is acquired by the radiation detector without rotating the radiation source;
Determining a parameter relating to shooting corresponding to the shooting mode based on the information indicating the positional relationship;
And a step of controlling the radiation detector based on the determined parameter.

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