JP3685546B2 - X-ray imaging method and X-ray CT apparatus - Google Patents

Description

[0001]
[Field of use to which the invention belongs]
The present invention relates to an improvement in image reconstruction of an X-ray CT (Computed Tomography) apparatus, and more particularly to an X-ray imaging method and an X-ray CT apparatus that can be operated by an operator in a scan room.
[0002]
[Prior art]
An X-ray CT apparatus is an apparatus that irradiates X-rays over the entire circumference of a subject, detects this with a detection device, reconstructs a tomographic image, and uses it for diagnosis.
[0003]
A schematic configuration of the X-ray CT apparatus is shown in FIG. In FIG. 6, reference numeral 10 denotes an operation console for performing various operations. In addition to various switches, the operation console 10 is provided with a scan start switch 11 for starting scanning.
[0004]
An X-ray generator 32 generates a high voltage necessary for X-ray irradiation in synchronization with an X-ray ON signal in accordance with a tube current / tube voltage setting signal from the console 10, and 33 is a gantry according to a gantry rotation control signal from the console 10. It is a gantry rotation control device that controls the rotation of a rotating unit.
[0005]
Reference numeral 50 denotes a gantry that performs X-ray irradiation and imaging on a subject, and includes a gantry rotating unit that rotates an X-ray tube and an X-ray detector described later. Reference numeral 51 denotes an X-ray tube that performs X-ray irradiation to perform X-ray tomography, and irradiates the subject in the image reconstruction area. 52 is a subject irradiated with X-rays from the X-ray tube 51, and is placed on a table not shown in the figure.
[0006]
Reference numeral 53 denotes an X-ray detector that detects X-rays irradiated from the X-ray tube 51 and transmitted through the subject 52, and generates an electric signal proportional to the X-ray energy, and includes a large number of detection elements.
[0007]
Reference numeral 54 denotes a data collection device (DAS) that collects electrical signals generated by the X-ray detector 53, and collects signals (raw data) proportional to the X-ray energy from the X-ray detector 53. To do.
[0008]
An image reconstruction device 60 reconstructs an image by back projecting the raw data, and further generates image data from the reconstructed data.
Reference numeral 80 denotes an operation console image display device, which is an image display means for displaying the reconstructed image in the vicinity of the operation console 10. Reference numeral 90 denotes an image display device for a scan room, which is an image display means for displaying a reconstructed image in the scan room.
[0009]
In such an X-ray CT apparatus, an X-ray tube 51 irradiates a subject 52 with a fan-shaped X-ray beam, and the transmitted X-rays are arranged in accordance with the spread of the fan-shaped X-ray beam. Measurement is performed by an X-ray detector 53 of a one-dimensional array made up of detection elements.
[0010]
The measurement of the transmitted X-ray is performed in a plurality of view directions while rotating the X-ray tube 51 and the X-ray detector 53 around the subject 52. Such measurement of transmitted X-rays is called a scan, and one image is reconstructed in units of one rotation (360 °) or half rotation (180 °).
[0011]
In general X-ray CT apparatuses such as those described above, raw data of about 1000 views per round is generated by scanning, and image reconstruction is performed.
[0012]
Then, a tomographic image of the subject 52 is reconstructed in the image reconstruction device 60 based on the measurement data of a plurality of views obtained by scanning. The reconstructed image data is displayed on the operation console image display device 80 and the scan room image display device 90.
[0013]
In the above X-ray CT apparatus, the operation console 10 and the operation console image display device 80 are installed in the operation room, and the gantry 50 and the scan room image display device 90 are installed in the scan room.
[0014]
[Problems to be solved by the invention]
In the case of the X-ray CT apparatus as described above, by setting the X-ray tube current and the tube voltage from the operation console 10 in advance before starting the scan, by pressing the scan start switch 11 installed on the operation console 10, A rotating part in the gantry 50 is rotated to emit X-rays.
[0015]
With such an X-ray CT apparatus, CT fluoroscopy (X-ray irradiation) is used to continuously observe the X-ray image of the physiological movement in the subject, the positional relationship of the organ, and morphological changes. When the method is performed, it is necessary to keep the X-ray tube current low in consideration of the X-ray exposure to the subject 52 and the operator in the scan chamber. On the other hand, if the X-ray tube current is suppressed, there is a problem that the image quality of an image obtained by reconstruction is deteriorated.
[0016]
Further, since X-ray irradiation control is automatically performed according to a scan plan set in advance in the operation console 10 in the operation room, X-ray irradiation may occur even when X-ray irradiation is not necessary. .
[0017]
Therefore, X-ray irradiation or the like when the operator is performing a biological tissue examination on the subject 52 cannot control the X-ray irradiation from within the scan chamber, and thus the subject 52 and the operator are useless. Will be exposed.
[0018]
The present invention has been made in view of the above points, and an object thereof is to realize an X-ray imaging method and an X-ray CT apparatus capable of being operated by an operator in a scan room.
[0019]
[Means for Solving the Problems]
The present invention as means for solving the problems is as described in the following (1) to (5).
[0020]
(1) The first invention controls the X-ray irradiation at a timing synchronized with the rotation of the gantry in accordance with an X-ray ON signal from the operation console and an operation of the X-ray switch in the scan chamber. It is a shooting method.
[0021]
In the X-ray imaging method according to the first aspect of the invention, when an X-ray on signal is output from the operation console and the X-ray switch in the scan room is operated, X-ray irradiation is performed at a timing synchronized with the rotation of the gantry. Control is done to do.
[0022]
As a result, the X-ray irradiation can be controlled from within the scanning chamber, so that the subject and the operation can be performed even when the operator performs a biological tissue examination on the subject. People will not receive unnecessary exposure.
[0023]
(2) The second invention is provided with X-ray control means for controlling X-ray irradiation at a timing synchronized with the rotation of the gantry in accordance with the X-ray ON signal from the operation console and the operation of the X-ray switch in the scan chamber. This is an X-ray CT apparatus.
[0024]
In the X-ray CT apparatus according to the second aspect of the invention, when an X-ray ON signal is output from the operation console and the X-ray switch in the scan chamber is operated, X-ray irradiation is performed at a timing synchronized with the rotation of the gantry. Control is done to do.
[0025]
As a result, the X-ray irradiation can be controlled from within the scanning chamber, so that the subject and the operation can be performed even when the operator performs a biological tissue examination on the subject. People will not receive unnecessary exposure.
[0026]
(3) The third invention is such that the state of the X-ray does not change during a period necessary for the X-ray control means in the X-ray CT apparatus of the second invention to reconstruct at least one image. Control is performed.
[0027]
In the X-ray CT apparatus according to the third aspect of the present invention, when the X-ray on signal is output from the operation console and the X-ray switch in the scan chamber is operated, the timing is synchronized with the rotation of the gantry at least. Control is performed so that X-ray irradiation is performed during a period necessary to reconstruct one image.
[0028]
As a result, the X-ray irradiation can be controlled with a simple switch operation from within the scanning chamber, so that the X-ray irradiation is performed when the operator is performing a biological tissue examination on the subject. For example, the subject and the operator are not exposed to unnecessary exposure.
[0029]
(4) A fourth invention is the X-ray CT apparatus according to the second invention, wherein a tube current increase switch for temporarily increasing a tube current supplied to the X-ray tube is provided in the scan chamber or the operation chamber. is there.
[0030]
In the X-ray CT apparatus according to the fourth aspect of the invention, an operation for temporarily increasing the tube current supplied to the X-ray from the scan chamber or the operation chamber can be performed as necessary. As a result, the X-ray dose can be increased from the scanning chamber or the operation chamber as necessary, so that the normal X-ray dose can be kept low. For this reason, the subject and the operator are not subjected to unnecessary exposure even by X-ray irradiation or the like when the operator is performing a biological tissue examination on the subject.
[0031]
(5) A fifth invention is the X-ray CT apparatus according to the second invention, wherein a control switch for controlling when displaying the reconstructed image is provided in the scan chamber.
[0032]
In the X-ray CT apparatus according to the fifth aspect of the present invention, various control operations can be performed when an image is displayed from the scan room. Various controls in this case correspond to window level, window width, and the like.
[0033]
As a result, the window level and window width of the image reconstructed from the scan room can be changed as necessary, so that a desired image can be displayed from the scan room. For this reason, even when X-ray irradiation is performed when the operator is performing a biological tissue examination on the subject, it is possible to accurately grasp the state of the biological tissue examination. Can be completed in a short time.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
FIG. 1 is a block diagram showing a configuration of an apparatus (X-ray CT apparatus) used in an X-ray imaging method according to an embodiment of the present invention and an X-ray CT apparatus according to an embodiment of the present invention.
[0035]
FIG. 2 is a flowchart showing a procedure of X-ray irradiation in the X-ray imaging method according to the embodiment of the present invention. FIG. 3 is a time chart in the X-ray imaging method according to the embodiment of the present invention. is there.
[0036]
<Configuration of X-ray CT apparatus (1)>
First, the configuration of an X-ray CT apparatus used in an X-ray imaging method according to an embodiment of the present invention and an X-ray CT apparatus according to an embodiment of the present invention will be described with reference to FIG. Do.
[0037]
In FIG. 1, reference numeral 10 denotes an operation console for performing various operations. In addition to various switches, the operation console 10 is provided with a scan start switch 11 for starting scanning.
[0038]
Reference numeral 21 denotes a tube current increase switch which is disposed in the scan chamber and performs an operation of temporarily increasing the tube current of the X-ray tube. Here, the tube current increase switch is shown disposed in the scan chamber. However, it is also possible to arrange the tube current increase switch in the scan chamber (such as on the operation console), which is advantageous in terms of exposure.
[0039]
Reference numeral 22 denotes an X-ray on switch for the scan chamber that is arranged in the scan chamber and generates an X-ray on signal for starting X-ray irradiation. The tube current increasing switch 21 and the scan room X-ray on switch 22 are preferably composed of foot switches and the like from the viewpoint of ease of operation.
[0040]
Reference numeral 23 denotes a gantry rotation synchronization control device for generating an X-ray ON signal in synchronization with the gantry rotation when the scan room X-ray ON switch 22 is pressed.
[0041]
Here, the X-ray on signal in synchronization with the gantry rotation means that the X-ray on signal starts to turn on in a state where the gantry rotating part has a predetermined rotation angle, and at least one image is reconstructed. This means that the X-ray irradiation is performed up to a predetermined rotation angle necessary for the above.
[0042]
31 is a tube current increaser that instructs the X-ray generator 32 to increase the tube current in accordance with the depression of the tube current increase switch 21, and is realized by changing the X-ray tube current setting signal from the operation console 10. Yes.
[0043]
An X-ray generator 32 generates a high voltage necessary for X-ray irradiation in synchronization with an X-ray ON signal in accordance with a tube current / tube voltage setting signal from the console 10, and 33 is a gantry according to a gantry rotation control signal from the console 10. It is a gantry rotation control device that controls the rotation of a rotating unit.
[0044]
Reference numeral 40 denotes a mode switching unit for switching the X-ray on signal between the operation console initiative mode and the scan room initiative mode, and includes a logic circuit 41 and a changeover switch 42.
[0045]
Here, the logic circuit 41 generates a logical sum (or a logical operation result equivalent to this) of the X-ray on signal from the operation console 10 and the X-ray on signal from the scan room. The changeover switch 42 selectively selects the X-ray on signal from the operation console 10 and the X-ray on signal from the logic circuit 41 and supplies the selected signal to the X-ray generator 32.
[0046]
Reference numeral 50 denotes a gantry that performs X-ray irradiation and imaging on a subject, and includes a gantry rotating unit that rotates an X-ray tube and an X-ray detector described later. Reference numeral 51 denotes an X-ray tube that performs X-ray irradiation to perform X-ray tomography, and irradiates the subject in the image reconstruction area. 52 is a subject irradiated with X-rays from the X-ray tube 51, and is placed on a table not shown in the figure.
[0047]
Reference numeral 53 denotes an X-ray detector that detects X-rays irradiated from the X-ray tube 51 and transmitted through the subject 52, and generates an electric signal proportional to the X-ray energy, and includes a large number of detection elements.
[0048]
Reference numeral 54 denotes a data collection device (DAS) that collects electrical signals generated by the X-ray detector 53, and collects signals (raw data) proportional to the X-ray energy from the X-ray detector 53. To do.
[0049]
An image reconstruction device 60 reconstructs an image by back projecting the raw data, and further generates image data from the reconstructed data.
Reference numeral 80 denotes an operation console image display device, which is an image display means for displaying the reconstructed image in the vicinity of the operation console 10. Reference numeral 90 denotes an image display device for a scan room, which is an image display means for displaying a reconstructed image in the scan room.
[0050]
In the above configuration, the X-ray control means for controlling the X-ray irradiation at the timing synchronized with the rotation of the gantry is constituted by the gantry rotation synchronization control device 23, the mode switching unit 40, and the X-ray generator 32.
[0051]
In such an X-ray CT apparatus, an X-ray tube 51 irradiates a subject 52 with a fan-shaped X-ray beam, and the transmitted X-rays are arranged in accordance with the spread of the fan-shaped X-ray beam. The measurement is performed by an X-ray detector 53 of a one-dimensional array comprising the detection elements.
[0052]
The measurement of the transmitted X-ray is performed in a plurality of view directions while rotating the X-ray tube 51 and the X-ray detector 53 around the subject 52. Such measurement of transmitted X-rays is called a scan, and one image is reconstructed in units of one rotation (360 °) or half rotation (180 °).
[0053]
Then, a tomographic image of the subject 52 is reconstructed in the image reconstruction device 60 based on the measurement data of a plurality of views obtained by scanning. The reconstructed image data is displayed on the operation console image display device 80 and the scan room image display device 90.
[0054]
In the above X-ray CT apparatus, the operation console 10 and the operation console image display device 80 are installed in the operation room, and the tube current increasing switch 21, the scan room X-ray on switch 22, the gantry 50, and the scan room. The image display device 90 is installed in the scan room.
[0055]
<Processing procedure of X-ray imaging method (1)>
The procedure of the X-ray imaging method according to the embodiment of the present invention and the operation of the X-ray CT apparatus according to the embodiment of the present invention are broadly divided into the following (1) and (2). , {Circle over (3)}.
[0056]
Hereinafter, this procedure will be described step by step according to each step. Here, the description will be given with reference to the time chart shown in FIG. FIG. 3 shows a case where X-ray irradiation is performed by the scan room X-ray ON switch 22 (scan room initiative mode).
[0057]
(1) Scan start:
First, prior to the start of scanning, the operator sets the scan mode on the operation console 10.
[0058]
The scan mode includes an operation console initiative mode in which scanning is started by pressing the scan start switch 11 of the operation console 10, and a scan room X-ray on switch 22 in a state where the start switch 11 of the operation console 10 is pressed. There is prepared a scan room initiative mode in which scanning is started when is pressed. The switching state of the selector switch 42 of the mode switching unit 40 is controlled by setting the scan mode.
[0059]
When the scan start switch 11 is pressed as shown in FIG. 3A with the scan mode set in this way, the operation console 10 generates an X-ray on signal (FIG. 3B). .
[0060]
(2) X-ray irradiation:
If the scan mode is the operation console initiative mode in this state, the changeover switch 42 supplies the X-ray ON signal from the operation console 10 to the X-ray generator 32 as it is. Accordingly, the X-ray tube 51 starts X-ray irradiation as the scan start switch 11 is pressed, as in the conventional normal operation.
[0061]
In this state, if the scan mode is the scan room initiative mode, the changeover switch 42 supplies the output of the logic circuit 41 to the X-ray generator 32.
[0062]
When the scan room X-ray ON switch 22 is pressed, an X-ray ON signal is output from the gantry rotation synchronization control device 23, and this X-ray ON signal generates one image in synchronization with the gantry rotation. Output over the required period.
[0063]
That is, the X-ray on signal from the gantry rotation synchronization control device 23 based on the depression of the scan room X-ray on switch 22 is logically summed (or equivalent) with the X-ray on signal on the operation console 10 side in the logic circuit 41. The logical result) is required.
[0064]
For this reason, among the X-ray ON signals from the scan room, the X-ray ON signal on the operation console side is not output for (1) in FIG.
[0065]
Among the X-ray on signals from the scan room, the X-ray on signal on the operation console side is output for (2) in FIG. 3C, and the logic circuit 41 outputs the X-ray on signal as a logical sum. Is output.
[0066]
Here, even if the scan room X-ray on switch 22 is pressed for a short time (FIG. 3 (c) (2)), the gantry rotation synchronization control device 23 synchronizes with the gantry rotation and at least one image is displayed. X-ray on signal is generated so that the state of the X-ray does not change during a period necessary for reconfiguring (for example, one rotation of the gantry). Therefore, X-ray irradiation is performed in synchronization with the gantry rotation (2) (FIGS. 2S4, S5, and S6: FIG. 3E).
[0067]
Also, when the scan room X-ray on switch 22 is depressed for a plurality of gantry rotation periods (FIG. 3 (c) (3)), the gantry rotation synchronization control device 23 is synchronized with the gantry rotation. The X-ray ON signal is generated so that the X-ray state does not change during a period necessary to reconstruct a plurality of images in that period. Accordingly, X-ray irradiation is performed in synchronization with the gantry rotations (3) to (4) (FIGS. 2S4, S5 and S6: FIG. 3E).
[0068]
Then, by operating the tube current increasing switch 21 for the scan chamber, it is possible to temporarily increase the tube current supplied to the X-rays from the scan chamber as necessary. The same can be said by operating a tube current increase switch (not shown) arranged in the operation chamber.
[0069]
As a result, the X-ray dose can be increased from within the scan chamber as needed to obtain a high-quality image, and thus the normal X-ray dose can be kept low. For this reason, the operator is not subjected to useless exposure even with X-ray irradiation or the like when the operator is performing a biological tissue examination on the subject.
[0070]
(3) Image reconstruction:
Then, the image reconstruction device 60 performs image reconstruction based on the raw data obtained by X-ray irradiation to generate image data (FIGS. 3 (f) (2), (4) to (5)). Then, the image data is displayed on the operation console image display device 80 and the scan room image display device 90 under the control of the image display control device 70 (FIGS. 3 (g) (2), (4) to (5). )).
[0071]
Here, the image display control device 70 has a function of freezing the image display except when an effective image (an image reconstructed by X-ray irradiation) comes. Therefore, the image data by the gantry rotation (2) is continuously displayed until the image data by the gantry rotation (4) is displayed.
[0072]
<Effects obtained by X-ray photography>
As described above, the scan room initiative mode is set, and the X-ray irradiation is performed by pressing the scan room X-ray on switch 22 installed in the scan room, so that the user is in the scan room. X-ray irradiation can be performed only when the operator determines that X-ray irradiation is necessary, and wasteful exposure of both the operator and the subject can be suppressed.
[0073]
Further, since the logic circuit 41 is provided to obtain the logical result of both X-ray on signals, the scan room X-ray on switch 22 is pressed when the X-ray on signal on the operation console 10 side is not output. However, X-rays are not irradiated. Therefore, X-ray irradiation due to an incorrect operation can be prevented.
[0074]
<Operation example (1)>
Here, the X-ray imaging as described above will be described in the case where the specific operation of the operator is a biological tissue examination.
[0075]
(1) First, the operator scans a portion that seems to be a tumor by a normal scan, and confirms the presence and location of the tumor.
(2) Then, the scan mode is set from the operation console 10. Here, the case where the scan room initiative mode is set is taken as an example. In addition, the X-ray tube current in the scan room initiative mode is set to a low value. As a result, the selector switch 42 of the mode switching unit 40 is switched to the logic circuit 41 side.
[0076]
(3) The operator presses the scan start switch 11 on the operation console 10. Thereby, the gantry rotating part in the gantry 50 starts rotating, and when X-rays are irradiated, the raw data can be acquired by the X-ray detector 53. However, since the scan room X-ray ON switch 22 is not pressed, the X-ray is not irradiated.
[0077]
(4) The operator presses the scan room X-ray on switch 22 at a desired timing such as checking the tip of the needle while inserting the needle into the subject for biological tissue examination. Even if the X-ray on switch 22 for the scan room is pressed for a short period, the period required for the gantry rotation synchronization control device 23 to reconstruct at least one image in synchronization with the gantry rotation is the X-ray. The X-ray on signal is generated so that the state does not change. Therefore, X-ray irradiation is performed in synchronization with the gantry rotation.
(5) Accompanying this X-ray irradiation, data collection and image reconstruction are performed, and image data is displayed on the operation console image display device 80 and the scan room image display device 90. The operator further pierces the needle while viewing the image display on the image display device 90 for the scan room.
[0078]
(6) If an image with high contrast and resolution is required when X-rays are being emitted, the operator presses the tube current increase switch 21 to increase the X-ray tube current, resulting in a high-quality image. Is obtained. Since this tube current increase switch 21 is provided in the scan chamber, it is possible to increase the tube current after the operator releases his / her hand from the scan surface (or needle). Therefore, the operator can avoid exposure.
[0079]
(7) Then, when the X-ray irradiation for a predetermined period is performed after the scan room X-ray on switch 22 is pressed and turned off, the image freeze control function of the image display control device 70 operates to reconfigure the image. The last valid image remains displayed.
[0080]
<8> Repeat the above steps from <4> to <7>, and when the operator finally confirms that the needle has reached the target, release the needle and perform the same operation as above <6> Increase the tube current and scan. Thereby, an evidence image that the needle has surely reached the target can be obtained as a higher quality image.
[0081]
Since the logic circuit 41 is provided to obtain the logical result of both X-ray on signals, the scan room X-ray on switch 22 is erroneously set when the X-ray on signal on the operation console 10 side is not output. X-rays are not irradiated even when pressed.
[0082]
<Example of actual arrangement>
FIG. 4 is an actual layout diagram showing the state of the operation room 100 and the scan room 200. Here, the operation console 10 in the operation room 100 and the gantry 50 in the scan room 200 are mainly shown.
[0083]
In the scan chamber 200, a foot switch 20 is disposed near the feet of the table 55. The foot switch 20 constitutes a tube current increase switch 21 and a scan room X-ray on switch 22.
[0084]
By providing the foot switch 20 in this manner, X-ray irradiation can be instructed when necessary even while the operator is pricking the needle. Further, the operation of the gantry rotation synchronization control device 23 may be a period in which the scan room X-ray on switch 22 is pressed for a short time, and the operability is good.
[0085]
<Configuration of X-ray CT apparatus (2)>
Here, the X-ray CT apparatus used in the X-ray imaging method according to the second embodiment of the present invention and the configuration of the X-ray CT apparatus according to the second embodiment of the present invention are shown in FIG. A description will be given using.
[0086]
Here, an X-ray CT apparatus is shown in which other switches are provided in the scan chamber 200 in addition to the tube current increase switch 21 and the scan chamber X-ray on switch 22 to further facilitate the operation.
[0087]
5 differs from FIG. 1 described above in that a WL foot switch 24 and a WW foot switch 25 are provided. The image display control device 70 is configured to be able to control WL and WW of an image to be displayed in response to operations of the WL foot switch 24 and the WW foot switch 25.
[0088]
The WL foot switch 24 and the WW foot switch 25 are preferably foot switches having up and down pedals for easy operation.
[0089]
Here, WL (window level) and WW (window width) will be described.
In a medical diagnostic apparatus such as an X-ray CT apparatus, image data of a tomographic image of a subject is generated and displayed on an image display apparatus such as a CRT display. In such a case, the pixel value of the image data (CT value in the case of an X-ray tomography apparatus) is determined by the X-ray transmittance, and generally is -1000 for air, 0 for water, and +2000 for bone. It is determined to be.
[0090]
Then, the pixel value of such image data is converted into display data of about 256 gradations to display an image. In this case, the number of gradations of the display data varies depending on the circuit configuration of the image display circuit or the CRT display, but generally, the number of gradations is about 256 gradations for processing the density data with 8 bits. A range such as −1000 to +2000 of pixel values of image data is not displayed as it is.
[0091]
Therefore, if the entire range of pixel values of the image data is assigned to the display data, −1000 to +2000 is assigned to 256 gradations in the above example, making it difficult to display fine gradation changes. Become. For example, since the pixel values of the organ of the subject to be noted are distributed between −150 and +150, there is a problem that the whole organ is displayed with the same gradation.
[0092]
Therefore, the concept of window width (WW) is introduced, image data within the range of the upper limit value and the lower limit value of the window width is converted into display data, and an image is displayed in shades. Display in white or black, and display in black or white where the lower limit is not met. By doing so, it becomes possible to display a change in the range of image data to be noticed.
[0093]
The range of image data to be converted into display data for such display is called the window width (WW), and the center value of the window width is called the window level (WL).
[0094]
Therefore, image data converted according to the value input by the operator via the WL foot switch 24 and the WW foot switch 25 is generated by the image display control device 70, and the image display is made on the CRT display device 70. That is, image data of CT values in a range desired by the operator is displayed in shades.
[0095]
By adopting such a configuration, there is an advantage that the operation in the scan chamber 200 can be performed even when such WL and WW operations are repeated by changing the window level.
[0096]
That is, it is possible to accurately grasp the state of the biological tissue examination, and to finish the biological tissue examination and X-ray irradiation in a short time. Therefore, the result of X-ray irradiation can be used effectively.
[0097]
Further, by providing a cursor control switch in addition to the WL foot switch 24 and the WW foot switch 25, it is possible to instruct cursor movement or cursor enlargement from the scan room 200. Even in this way, various operations from the scan chamber can be easily performed, so that the result of X-ray irradiation can be used effectively.
[0098]
It should be noted that various image display related controls other than the WW, WL, and cursor control shown here can be performed by the foot switch 20. By controlling the various image display relationships in this way, the operability in the scan chamber 200 when performing a biological tissue examination or the like is improved.
[0099]
<Effects obtained by embodiment: Comparison with conventional example>
As described above, the X-ray imaging method and the X-ray CT apparatus control the X-ray irradiation at the timing synchronized with the rotation of the gantry according to the X-ray ON signal from the operation console and the operation of the X-ray switch in the scan room. According to this, the effects described below can be obtained.
[0100]
(1) As a result of controlling the X-ray irradiation at the timing synchronized with the rotation of the gantry according to the X-ray ON signal from the operation console and the operation of the X-ray switch in the scan room, the X-ray irradiation is controlled from the scan room. Therefore, the subject and the operator are not subjected to unnecessary exposure even by X-ray irradiation or the like when the operator is performing a biological tissue examination on the subject.
[0101]
(2) The X-ray control described in (1) above is performed so that the X-ray state does not change during a period necessary to reconstruct at least one image. Since the X-ray irradiation can be controlled by the switch operation, the subject and the operator can use the exposure unnecessarily even when the operator performs a biological tissue examination on the subject. I will not receive it.
[0102]
(3) A tube current increase switch that temporarily increases the tube current supplied to the X-ray tube is provided in the scan chamber, and if necessary, the tube current supplied to the X-ray from the scan chamber can be temporarily increased. As a result, the X-ray dose can be increased from the scanning chamber as necessary, so that the normal X-ray dose can be kept low. For this reason, the subject and the operator are not subjected to unnecessary exposure even by X-ray irradiation or the like when the operator is performing a biological tissue examination on the subject.
[0103]
(4) Result of having a control switch for controlling when displaying the reconstructed image in the scan room, and enabling various control operations (window level and window width operations) when displaying the image from the scan room Since the window level and the window width of the image reconstructed from the scan room can be changed as necessary, it is possible to display a desired image from the scan room. For this reason, even when X-ray irradiation is performed when the operator is performing a biological tissue examination on the subject, it is possible to accurately grasp the state of the biological tissue examination. Can be completed in a short time.
[0104]
【The invention's effect】
According to the X-ray imaging method and the X-ray CT apparatus described in detail above, the following effects (1) to (5) can be obtained.
[0105]
(1) In the X-ray imaging method of the first invention, when an X-ray ON signal is output from the operation console and the X-ray switch in the scan room is operated, X-ray irradiation is performed at a timing synchronized with the rotation of the gantry. Control is performed so that
[0106]
As a result, the X-ray irradiation can be controlled from within the scanning chamber, so that the subject and the operation can be performed even when the operator performs a biological tissue examination on the subject. People will not receive unnecessary exposure.
[0107]
(2) In the X-ray CT apparatus of the second invention, when an X-ray on signal is output from the operation console and the X-ray switch in the scan chamber is operated, X-ray irradiation is performed at a timing synchronized with the rotation of the gantry. Control is performed so that
[0108]
As a result, the X-ray irradiation can be controlled from within the scanning chamber, so that the subject and the operation can be performed even when the operator performs a biological tissue examination on the subject. People will not receive unnecessary exposure.
[0109]
(3) In the X-ray CT apparatus of the third invention, the X-ray control means in the X-ray CT apparatus of the second invention outputs an X-ray on signal from the operation console and the X-ray switch in the scan chamber When operated, control is performed so as to perform X-ray irradiation at a timing synchronized with the rotation of the gantry and for a period necessary to reconstruct at least one image.
[0110]
As a result, the X-ray irradiation can be controlled with a simple switch operation from within the scanning chamber, so that the X-ray irradiation is performed when the operator is performing a biological tissue examination on the subject. For example, the subject and the operator are not exposed to unnecessary exposure.
[0111]
(4) In the X-ray CT apparatus of the fourth invention, in the X-ray CT apparatus of the second invention, a tube current increase switch for temporarily increasing the tube current supplied to the X-ray tube is provided in the scan chamber or the operation chamber. It is possible to perform an operation of temporarily increasing the tube current supplied to the X-ray from the scanning chamber or the operation chamber as necessary.
[0112]
As a result, the X-ray dose can be increased from the scanning chamber or the operation chamber as necessary, so that the normal X-ray dose can be kept low. For this reason, the subject and the operator are not subjected to unnecessary exposure even by X-ray irradiation or the like when the operator is performing a biological tissue examination on the subject.
[0113]
(5) In the X-ray CT apparatus of the fifth invention, the X-ray CT apparatus of the second invention is provided with a control switch for controlling when displaying the reconstructed image in the scan chamber, and the image from the scan chamber Various control operations can be performed when displaying. Various controls in this case correspond to window level, window width, and the like.
[0114]
As a result, the window level and window width of the image reconstructed from the scan room can be changed as necessary, so that a desired image can be displayed from the scan room. For this reason, even when X-ray irradiation is performed when the operator is performing a biological tissue examination on the subject, it is possible to accurately grasp the state of the biological tissue examination. Can be completed in a short time.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a configuration example of an X-ray CT apparatus according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing a procedure of an X-ray imaging method according to the first embodiment of the present invention.
FIG. 3 is a time chart showing the procedure of the X-ray imaging method of the first embodiment of the present invention.
FIG. 4 is an actual layout diagram showing a state of an operation room and a scan room.
FIG. 5 is a configuration diagram showing a configuration example of an X-ray CT apparatus according to a second embodiment of the present invention.
FIG. 6 is a configuration diagram showing a configuration example of a main part of a conventional X-ray CT apparatus.
[Explanation of symbols]
10 Operation console
11 Scan start switch
20 Foot switch
21 Tube current increase switch
22 X-ray on switch for scan room
23 Gantry rotation synchronous control device
31 tube current increaser
32 X-ray generator
33 Gantry rotation control device
40 Mode switching part
41 logic circuit
42 selector switch
50 Gantry
51 X-ray tube
52 subjects
53 X-ray detector
54 Data collection device
60 Image reconstruction device
70 Image display controller
80 Image display device for operation console
90 Image display device for scan room

Claims (5)

When the gantry having the X-ray tube and the X-ray detector rotates the X-ray tube and the X-ray detector around the subject, the X-ray detector reconstructs at least one CT image. In the X-ray imaging method of the X-ray CT apparatus in which the X-ray tube continuously emits X-rays in order to collect data necessary for
According to the X-ray ON signal from the operation console and the X-ray switch in the scan room, the X-ray irradiation is controlled at a timing synchronized with the rotation of the gantry,
An X-ray imaging method comprising irradiating X-rays when the tube current increases when a tube current increase switch that temporarily increases a tube current supplied to the X-ray tube is used. When the gantry having the X-ray tube and the X-ray detector rotates the X-ray tube and the X-ray detector around the subject, the X-ray detector reconstructs at least one CT image. In the X-ray CT apparatus in which the X-ray tube continuously emits X-rays in order to collect data necessary for
According to the X-ray ON signal from the operation console installed in the operation room and the X-ray switch of the scan room in which the gantry is installed, the X-ray irradiation is controlled by the X-ray tube at a timing synchronized with the rotation of the gantry. With X-ray control means,
A tube current increase switch for temporarily increasing the tube current supplied to the X-ray tube is provided in the scan chamber or the operation chamber,
An X-ray CT apparatus for obtaining a CT image by X-rays when the tube current increases when the tube current increase switch is used.   The X-ray control apparatus according to claim 2, wherein the X-ray control means performs control so that the state of the X-ray does not change during a period required to reconstruct at least one image. CT device.   The X-ray CT apparatus according to claim 2, further comprising a window level foot switch and a window width foot switch for displaying the reconstructed image in the scan chamber.   The X-ray control means irradiates X-rays from the X-ray tube when both an X-ray on signal from the operation console and an X-ray on signal from an X-ray switch in the scan room are on. The X-ray CT apparatus according to any one of claims 2 to 4.

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