JP2000102527A - X-ray diagnostic instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a detection sensitivity of an X-ray surface sensor for detecting a transmission X-ray image suitable for the volume of incident X-rays. SOLUTION: In this radiography instrument, an applied voltage source 31 changes voltages to be applied to plural groups of X-ray detecting elements, which are set inside a panel type X-ray sensor 3, by the group based on the control by an applied voltage control part 32. The applied voltage control part 32 controls the voltages to be applied according to the level of strength of X-ray detection data outputted from the plural groups of X-ray detecting elements when X-rays are irradiated from an X-ray tube 2. Therefore, the detection sensitivity of the X-ray detecting elements in each group is made appropriate, so that the halation of a transmission X-ray image can be prevented and the quality of the image can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission X-ray based on X-ray detection data output from an X-ray surface sensor, which is a transmission X-ray image detector, when an X-ray tube irradiates a subject with X-rays.
The present invention relates to an X-ray diagnostic apparatus configured to obtain a line image,
The present invention relates to a technique for setting the detection sensitivity of an X-ray surface sensor, which is a transmission X-ray image detector, to an appropriate sensitivity corresponding to an incident X-ray dose.

[0002]

2. Description of the Related Art Conventionally, an X-ray fluoroscopic apparatus (X-ray diagnostic apparatus) installed in a medical institution such as a hospital or the like has a patient (patient) placed on a top 51 as shown in FIG. An X-ray tube 52 and an image intensifier 53 (abbreviated as “II tube” as appropriate), which is a transmission X-ray image detector, are disposed so as to face each other with the sample M interposed therebetween. X-ray tube 52
As a result, X-ray detection data for a transmitted X-ray image is output from the I / I tube 53 in accordance with the X-ray irradiation on the patient M by the above.

However, since the II tube 53 is a heavy object having a large volume, the mounting structure is complicated. Therefore, FIG.
As shown in the figure, a flat panel X
An apparatus using the line sensor 54 as a transmission X-ray image detector has been proposed. The flat panel type X-ray sensor 54 is an X-ray surface sensor in which a large number of X-ray detecting elements are arrayed vertically and horizontally. There is an advantage that a structure is sufficient.

[0004]

However, the X-ray fluoroscopic apparatus using the flat panel type X-ray sensor 54 has a problem that halation easily occurs in a transmitted X-ray image. In the conventional flat panel X-ray sensor 54, in order to secure sufficient intensity of X-ray detection data even when the incident X-ray dose is small, the applied voltage applied to the X-ray detection element is increased to increase the detection sensitivity. As shown by the solid line Na in FIG. 14, when the amount of incident X-ray is slightly increased, the X-ray detection data is immediately saturated. That is, in the case of the flat panel type X-ray sensor 54 having a high applied voltage, the so-called dynamic range Da is very narrow, and halation easily occurs.

[0005] If the applied voltage applied to the X-ray detecting element of the flat panel type X-ray sensor 54 is reduced, the detection sensitivity is lowered, and as shown by the dashed line Nb in FIG. Move to the one with the higher X-ray dose. That is, in the case of the flat panel type X-ray sensor 54 to which the applied voltage is low, the so-called dynamic range Db becomes very wide, so that halation hardly occurs. However, if the detection sensitivity of the flat panel type X-ray sensor 54 is low, the S / N ratio of the X-ray detection data is deteriorated, which causes another problem that the quality of the final transmitted X-ray image is deteriorated.

The present invention has been made in view of the above problems, and provides an X-ray diagnostic apparatus capable of setting the detection sensitivity of an X-ray surface sensor, which is a transmission X-ray image detector, to an appropriate sensitivity corresponding to an incident X-ray dose. That is the task.

[0007]

In order to solve the above-mentioned problems, an X-ray diagnostic apparatus according to the present invention is arranged such that an X-ray tube and a transmission X-ray image detector are opposed to each other with a subject interposed therebetween. X-rays that are provided and configured to obtain a transmission X-ray image based on X-ray detection data output from a transmission X-ray image detector when the X-ray tube irradiates the subject with X-rays The diagnostic apparatus includes, as a transmitted X-ray image detector, an X-ray surface sensor in which a number of X-ray detection elements are arranged vertically and horizontally, and an X-ray surface sensor according to the intensity level of the X-ray detection data. And an applied voltage control means for adjusting the detection sensitivity by changing the applied voltage applied to the X-ray detecting element.

According to a second aspect of the present invention, in the X-ray diagnostic apparatus according to the first aspect, the X-ray surface sensor is configured such that all the X-ray detecting elements are divided into at least two groups and each group is independently provided. The configuration is such that the applied voltage is applied, and the applied voltage control means can change the applied voltage for each group.

According to a third aspect of the present invention, there is provided the X-ray diagnostic apparatus according to the first or second aspect, wherein the data for compensating for a change in the intensity level of the X-ray detection data accompanying a change in the applied voltage by the applied voltage control means. An intensity compensation means is provided.

[Operation] Next, the operation of controlling the applied voltage of the X-ray detecting element during X-ray imaging by the X-ray diagnostic apparatus of the present invention will be described. In the X-ray imaging by the X-ray diagnostic apparatus according to the present invention, the control performed by the applied voltage control means according to the intensity level of the X-ray detection data output from the X-ray surface sensor with the X-ray irradiation by the X-ray tube is performed. The applied voltage applied to the X-ray detection element of the X-ray surface sensor is changed. Specifically, when the intensity level of the X-ray detection data is too high, the detection sensitivity is too high and the dynamic range is narrow,
Halation is likely to occur in the transmitted X-ray image. Thus, under the control of the applied voltage control means, the applied voltage applied to the X-ray detection element is reduced, the detection sensitivity of the X-ray detection element becomes appropriate, and the dynamic range is widened. As a result, halation does not occur.

In the X-ray diagnostic apparatus according to the second aspect, the applied voltage control means controls the applied voltage for each group according to the X-ray detection data of each group of the X-ray detecting elements divided into groups. An appropriate applied voltage is applied to the X-ray detection elements of the group. As a result, the detection sensitivity of the X-ray detection elements in each group becomes more appropriate according to the situation of the group.

In the X-ray diagnostic apparatus according to the third aspect, the data intensity compensating means compensates for the change in the intensity level of the X-ray detection data due to the change in the applied voltage, so that the X-ray detection data is independent of the change in the applied voltage. Is kept constant.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the X-ray diagnostic apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an entire configuration of an X-ray fluoroscopic apparatus according to an embodiment,
FIG. 2 is a block diagram showing a configuration of an applied voltage control system of a flat panel X-ray sensor (appropriately abbreviated as “panel X-ray sensor”) as an X-ray surface sensor, and FIG. 3 is a basic configuration of the panel X-ray sensor. FIG. 4 is a partial sectional view showing the internal configuration of the panel X-ray sensor.

As shown in FIG. 1, an X-ray fluoroscopic apparatus according to an embodiment includes an X-ray tube 2 and a panel as a transmission X-ray image detector with a subject M placed on a top plate 1 interposed therebetween. The X-ray tube 2 is disposed so as to face the X-ray sensor 3.
As a result, the transmitted X-ray image of the imaging region (interest) of the subject M is projected onto the detection area of the panel-type X-ray sensor 3 in accordance with the X-ray irradiation of the subject M. As shown in FIG. 3, the panel type X-ray sensor 3 has a large number of X-ray detection elements XD arranged in a matrix in a detection area, and a transmitted X-ray image projected on the detection area is X-ray image. After being converted into an electric signal by the line detection element XD, it is read out by the signal
It is output as X-ray detection data for a line image. Unlike the image intensifier, the panel-type X-ray sensor 3 is thin and lightweight, and therefore does not require a large-scale structure for mounting the panel-type X-ray sensor 3.

The top 1 is moved forward and backward, left and right or up and down under the control of the top driving unit 5 with the subject M placed thereon. That is, the top plate 1 is moved to
Is set to the imaging position of the apparatus.
The X-ray tube 2 normally irradiates a pulsed X-ray to an imaging region of the subject M at an appropriate timing under the control of the irradiation control unit 6. The apparatus according to the embodiment is an X-ray fluoroscopic apparatus capable of selectively performing X-ray fluoroscopic imaging and X-ray photography (book photography). In the case of X-ray fluoroscopic imaging, X-rays are continuously emitted with a small eye dose. X-rays are emitted one after another, and in the case of X-ray photography, X-rays are emitted one by one with a large eye dose. The control of the top driving unit 5 and the control of the irradiation control unit 6 are performed in accordance with a command signal output from the imaging control unit 9 in a timely manner in accordance with an input operation from the keyboard 7 or the hand switch 8. Has become.

On the other hand, the X-ray detection data output from the signal collecting unit 4 passes through a data intensity compensating unit 10 (to be described in detail later) and a changeover switch 11, and is converted into an AD conversion unit for converting the X-ray detection data into a digital signal. It is sent to 12. A
In the subsequent stage of the D conversion unit 12, a detection data memory 13 for storing digitized X-ray detection data, and necessary image processing such as edge enhancement and filtering is performed on the X-ray detection data stored in the detection data memory 12. By X
A data processing unit 14 for finishing a line image and an X-ray image memory 15 for storing a finished X-ray fluoroscopic image are continuously provided.

Further, a display monitor 1 for displaying a transmission X-ray image stored in the X-ray image memory 15 is provided in the embodiment apparatus.
6, an image storage memory 18 for storing and storing a transmission X-ray image as a digital image, or a printer (laser imager) 17 for printing a transmission X-ray image on a sheet and outputting it as an X-ray photograph. Have been. Normally, in X-ray fluoroscopy, a transmitted X-ray image is
Is converted into an analog signal and is continuously displayed on the screen of the display monitor 16. In radiography, transmission X
The sheet on which the line image is printed is output from the printer 18 as an X-ray photograph.

Next, the configuration around the panel type X-ray sensor 3 will be specifically described. The arrangement of the X-ray detection elements XD in the panel-type X-ray sensor 3 includes, for example, a square matrix configuration in a horizontal (x) direction 1024 and a vertical (y) direction 1024. The reading of the X-ray detection element XD is performed according to an x, y scanning signal (sweep signal) sent from the imaging control unit 9.

The panel type X-ray sensor 3 of the embodiment device is a so-called direct conversion type sensor, and as shown in FIG. 4, an X-ray conversion layer 20 for converting incident X-rays into electric charges, and an X-ray conversion layer. The device has a laminated structure with a detection array layer 21 in which elements for detecting charges generated in 20 are arranged vertically and horizontally in a matrix. For direct conversion type sensors,
The X-ray conversion layer 20 is made of a selenium layer or a CdZnTe layer that directly converts incident X-rays into charges, and has a charge collection electrode formed on the surface of the detection array layer 21 as a charge detection element 22 so as to face the surface electrode 23. The charge is detected and stored in the capacitor C1, and the stored charge is stored in the TFT (Thin Fil).
m Transister: a thin film transistor) 24, and one charge detection element 22;
One X-ray detection element XD is formed by a part of the X-ray conversion layer 20 thereon, the capacitor C1 and the TFT 24. Further, an applied voltage is supplied to the surface electrode 23 from an applied voltage power supply unit 31.

In the panel type X-ray sensor 3, FIG.
., XD are read wirings 25, 26 running vertically and horizontally through TFTs 24, respectively.
It is connected to the. The readout wirings 25 are connected to a horizontal (x) readout drive unit 27, respectively, and the readout wirings 26 are connected to a multiplexer 30 via a group of preamplifiers 29. The x and y scanning signals for reading are sent to the horizontal reading drive unit 27 and the multiplexer 30. The identification of each X-ray detection element XD of the panel type X-ray sensor 3 is sequentially assigned to each X-ray detection element XD along an array in the horizontal direction and the vertical direction.
, The scanning signal for reading out is a signal for designating a horizontal (x) direction address or a vertical (y) direction address, respectively.

In accordance with a horizontal scanning signal, a horizontal read driving section 27
As a voltage for reading is applied to the read wiring 25 from, each detection element XD is sequentially selected in column units. The multiplexer 30 according to the vertical scanning signal
Is switched, the X-ray detection data of each X-ray detection element XD in the selected column is sequentially collected and output via each preamplifier 29 and multiplexer 30 of the signal collection unit 4. The method of reading out the X-ray detection data from the panel type X-ray sensor 3 is almost the same as that of a general video detector such as a TV camera. In the case of the sensor 3 of the embodiment, the read-out drive unit 27, the preamplifier 29, and the multiplexer 30, which constitute the signal collection unit 4, are also installed on the surface periphery of the detection array layer 21 of the panel type X-ray sensor 3, The structure is further integrated. Also,
The detection data memory 13 for storing X-ray detection data obtained from the panel X-ray sensor 3 and the X-ray image memory 15 for storing X-ray fluoroscopic images are provided by the X-ray detection elements XD of the panel X-ray sensor 3. A frame memory type storage device having a matrix configuration corresponding to the vertical and horizontal matrix configuration is used.

The apparatus of the embodiment includes an X-ray detecting element X.
The applied voltage which determines the detection sensitivity of D is applied to the panel type X-ray sensor 3.
Of the panel type X-ray sensor 3 according to the intensity level of the X-ray detection data as a characteristic configuration of the present invention. An applied voltage control unit 32 for changing the applied voltage and a data intensity compensating unit 10 for compensating for a change in the intensity level of the X-ray detection data due to a change in the applied voltage are provided.

In addition, in the panel type X-ray sensor 3 of the apparatus of the embodiment, all the X-ray detecting elements XD have four groups G.
a to Gd, and as shown in FIG. 6, the surface electrode 23 is formed in a form divided into four divided electrodes 23a to 23d just corresponding to the areas of the four groups Ga to Gd. The voltage applied to the divided electrodes 23a to 23d is changed by the applied voltage controller 32 in accordance with the X-ray detection data of the corresponding groups Ga to Gd. Subsequently, a characteristic configuration of the present invention will be described more specifically.

The applied voltage control unit 32 receives an operation signal for designating any of X-ray fluoroscopy and X-ray photography received from the imaging control unit 9 and irradiation for instructing X-ray irradiation received from the irradiation control unit 6. The control is executed in accordance with a command issued from the imaging mode control unit 33 to the applied voltage control unit 32 in response to the signal. As shown in FIG. 2, the applied voltage control unit 32 has four electrode-based voltage control units 32a to 32d, and the electrode-based voltage control unit 32a controls the applied voltage of the X-ray detection element XD of the group Ga. And the voltage control unit 3 for each electrode
2b is in charge of controlling the applied voltage of the X-ray detection element XD of the group Gb, and the voltage control unit 32c for each electrode is
The configuration is in charge of controlling the applied voltage of the line detection element XD, and the voltage control unit 32d for each electrode is in charge of controlling the applied voltage of the X-ray detection element XD of the group Gd. On the other hand, the applied voltage power supply unit 31 has four independent power supplies 31a to 31d, and the independent power supply 31a applies an applied voltage to the divided electrodes 23a under the control of the electrode-specific voltage control unit 32a.
1b applies an applied voltage to the divided electrodes 23b according to the control of the electrode-specific voltage control unit 32b, and the independent power supply 31c applies the applied voltage to the divided electrodes 23 under the control of the electrode-specific voltage control unit 32c.
c, and the independent power supply 31 d
Is applied to the divided electrode 23d in accordance with the control of.

X-ray detecting elements XD of each group Ga to Gd
Is a sensitivity proportional to the magnitude of the applied voltage applied to each of the divided electrodes 23a to 23d. That is, in the case of a high applied voltage, as shown in FIG. 7A, the detection sensitivity (intensity of X-ray detection data / incident X-ray dose) of the X-ray detection element XD is high, and the dynamic range Da is narrow and low. In the case of the applied voltage, as shown in FIG. 7B, the detection sensitivity (intensity of X-ray detection data / incident X-ray dose) of the X-ray detection element XD is low, and the dynamic range Db is wide. In the case of the X-ray fluoroscopic apparatus of the embodiment, first, the independent power supply 31a
To 31d apply a high applied voltage to each of the divided electrodes 23a to 23d so that the detection sensitivity is sufficient.

In the case of X-ray fluoroscopy, X-ray detection data output from the X-ray detection signal XD of the group Ga is sequentially sent from the contact n1 of the switch 34 to the voltage control unit 32a via the contact a1. 8A, the average value of the data intensity is calculated, and as shown in FIG. 8A, the average value of the X-ray detection data intensity is compared with a predetermined threshold value Vm. The application of the current applied voltage VA is continued. Conversely, if the average value of the X-ray detection data intensities is higher than the threshold value Vm, the detection sensitivity is too high.
As shown in FIG. 8B, the voltage control unit 32a changes the control so that the current applied voltage VA from the independent power supply 31a is slightly reduced to become the applied voltage VB. FIG.
As shown in (b), the average value of the X-ray detection data is
If it is still higher than m, in the case of X-ray fluoroscopy, X-ray irradiation is continuously performed and X-ray detection data is repeatedly read and output. Is further reduced a little, and the reduction control of the applied voltage is performed again so as to become the applied voltage VC.

That is, in the case of X-ray fluoroscopy, if the average value of the X-ray detection data intensity is lower than the threshold value, the electrode-based voltage control unit 32a performs control for reducing the applied voltage until the detection sensitivity becomes appropriate. The changes are repeated. The control of the applied voltage by the other three electrode-specific voltage controllers 32b to 32d is substantially the same as that of the electrode-specific voltage controller 32a, except that the contact a1 of the changeover switch 34 is changed to the contacts b1 to d1. Therefore, the description is omitted. In the case of the embodiment device, as shown in FIG. 8B, one applied voltage control operation is performed while the X-ray detection data is read twice. Of course, each time the X-ray detection data is read once, the applied voltage control operation may be performed once.

In the case of X-ray photography, at a time Td when a predetermined time has elapsed from the start of X-ray irradiation, for example, the X-ray detection data of the group Ga is changed to the contact n1 of the changeover switch 34.
Are sequentially sent to the electrode-specific voltage control section 32a via the contact point a1, and the average value of the data intensity is calculated. The calculated average value is compared with a predetermined threshold value Vn as shown in FIG. 9A, and if the average value Vn of the X-ray detection data intensity is lower than the threshold value, the current applied voltage Va is directly used.
Keep giving. Conversely, if the average of the X-ray detection data intensities is higher than the threshold value Vn, the detection sensitivity is too high.
As shown in (b), the voltage control unit 32a for each electrode lowers the current applied voltage Va by the independent power supply 31a and applies the applied voltage Vb at which the X-ray detection data is predicted not to be saturated at the time Te when the X-ray irradiation ends. Change the control so that
Similarly, the other electrode-based voltage controllers 32b to 32d also control the applied voltage. The contact of the changeover switch 34 is switched by a command signal of the imaging control unit 9 so as to correspond to the group of the read X-ray detection data.

On the other hand, the data intensity compensating section 10 includes variable gain type amplifying sections 10a to 10d. The variable gain type amplifying section 10a performs a compensation process on the X-ray detection data of the group Ga, and 10b performs compensation processing on the X-ray detection data of the group Gb, the variable gain amplifier 10c performs compensation processing on the X-ray detection data of the group Gc, and the variable gain amplifier 10d performs the group Gd.
Is configured to perform compensation processing on the X-ray detection data.

In both X-ray fluoroscopy and X-ray photography, the gain-variable amplifying unit 10a controls the intensity of X-ray detection data by changing the applied voltage by controlling the gain of the control output of the voltage control unit 32a for each electrode. Compensate for fluctuations. That is, if the control output of the electrode-specific voltage control unit 32a is a command to lower the applied voltage, the detection sensitivity decreases and the intensity level of the X-ray detection data also decreases.
Increases the gain with the control output of the electrode-specific voltage control unit 32a, and sufficiently amplifies the X-ray detection data sequentially sent from the contact n1 of the changeover switch 11 via the contact a1 to the original intensity level. The X-ray detection data maintaining the original intensity level is sent from the contact a2 of the changeover switch 11 to the AD converter 12 via the contact n2.

Therefore, the gain of the variable gain amplifier 10a is controlled so as to be inversely proportional to the applied voltage. Other three variable gain type amplifiers 10b to 10d
The gain control by the variable gain amplifier 10 except that the contact a2 of the changeover switch 11 is changed to the contacts b2 to d2.
The description is omitted because it is substantially the same as the case a. The contact of the changeover switch 11 is switched in accordance with a group of X-ray detection data to be amplified according to a command signal from the imaging control unit 9. By compensating for the variation in the intensity level as described above, the output image displayed on the display monitor 16 or the like becomes an image having a smooth gradation change in which the influence of the change in the applied voltage does not appear.

Next, the operation of controlling the voltage applied to the X-ray detecting element XD when the image is taken by the embodiment apparatus having the above-described configuration will be described with reference to the drawings. First, the case of X-ray fluoroscopy will be described. FIG. 10 is a flowchart showing the progress of applied voltage control in X-ray fluoroscopy by the apparatus of the embodiment. [Step S1] After placing the subject M on the top 1, the top 1 is moved to set the imaging region of the subject M to the imaging position, and the hand switch 8 instructs X-ray fluoroscopy. I do.

[Step S2] X-rays are continuously emitted from the subject M
The X-ray detection data is sequentially read out from the X-ray detection element XD as the light is irradiated to
It is sent to 2d.

[Step S3] Each electrode voltage controller 32
a to 32d, the average value of the X-ray detection data and the threshold value Vm
Are compared with each other, so that the divided electrodes 23a to 23a
The appropriateness of the applied voltage d is checked. As a result of the check, if the applied voltage is appropriate, the process proceeds to step S5. If the applied voltage is not appropriate, the process proceeds to the next step S4.

[Step S4] The applied voltages of the independent power supplies 31a to 31d and the gains of the variable gain amplifiers 10a to 10d corresponding to the groups for which the applied voltages are not appropriate are adjusted to appropriate voltages by the control output of the electrode voltage control unit. Changed to gain.

[Step S5] If photographing is to be continued, the process returns to step S2, and the following steps are repeated. If the photographing is completed, the applied voltage control is also completed. In parallel with the control of the applied voltage, the X-ray detection data is processed into a transmission X-ray image after the fluctuation of the intensity level is compensated, and is displayed on the screen of the display monitor 16.

Next, the case of X-ray photography will be described. FIG. 11 is a flowchart illustrating the progress of applied voltage control in X-ray photography by the apparatus of the embodiment. [Step U1] After placing the subject M on the top 1, the top 1 is moved to set the imaging region of the subject M at the imaging position, and the hand switch 8 is used to instruct X-ray photography. I do.

[Step U2] When a certain period of time has elapsed since the start of irradiation of the subject M with X-rays and the time point Te is reached,
The X-ray detection data of the X-ray detection elements XD of each of the groups Ga to Gd are read out, and the voltage control units for each electrode 32a to 32d are read out.
It is sent to 2d.

[Step U3] Each electrode voltage controller 32
By comparing the average value of the X-ray detection data read by a to 32d with the threshold value Vn, it is checked whether the applied voltages to the divided electrodes 23a to 23d are appropriate. As a result of the check, if the applied voltage is appropriate, step U5
Proceed to. If the applied voltage is not appropriate, the next step U4
Proceed to.

[Step U4] The applied voltages of the independent power supplies 31a to 31d and the gains of the variable gain amplifiers 10a to 10d corresponding to the groups for which the applied voltages are not appropriate are adjusted to appropriate voltages by the control output of the electrode voltage control unit. Changed to gain.

[Step U5] An appropriate applied voltage is maintained until photographing is completed. If the photographing is completed, the applied voltage control is also completed. In parallel with the control of the applied voltage,
The X-ray detection data is formed into a transmission X-ray image, printed on a sheet by a printer 17 and output as an X-ray photograph.

As described in detail above, according to the X-ray fluoroscopic apparatus of the embodiment, the applied voltage applied to the X-ray detecting element XD of the panel type X-ray sensor 3 is controlled by the X-ray irradiation of the X-ray tube 2. Is changed in accordance with the intensity level of the X-ray detection data actually output from the panel type X-ray sensor 3 and the detection sensitivity of the X-ray detection element XD is automatically changed to an appropriate sensitivity. In addition to preventing halation from appearing in the image, the S / N ratio of the X-ray detection data is improved and the image quality is improved.

Further, according to the apparatus of the embodiment, the applied voltage of the X-ray detection element is changed according to the X-ray detection data of each group Ga to Gd of the X-ray detection element XD divided into four groups Ga to Gd. Given, the detection sensitivity of each of the groups Ga to Gd becomes more appropriate in accordance with the situation of each group, so that halation can be more reliably prevented, and the SN ratio becomes very good, and the image quality further improves. .

In addition, according to the apparatus of the embodiment, the fluctuation of the intensity level of the X-ray detection data accompanying the change of the applied voltage for improving the detection sensitivity is compensated. As a result, the intensity level of the detection data corresponds to the intensity of the transmitted X-ray, so that a high-quality X-ray image can be obtained.

The present invention is not limited to the above embodiment, but may be modified as follows. (1) The apparatus of the embodiment has a configuration in which both X-ray fluoroscopy and X-ray photography can be performed.
A configuration in which only one of fluoroscopy and X-ray photography can be performed may be employed.

(2) In the embodiment, the X-ray detecting elements are divided into four groups, and the applied voltage is changed for each group. The configuration may be such that the division is not performed at all and the applied voltage to all the X-ray detection elements can be changed uniformly. Conversely, the apparatus of the present invention may have a configuration in which the applied voltage of all the X-ray detection elements is controlled for each element.

(3) The apparatus used in the embodiment employs a direct conversion type X-ray surface sensor. However, the X-ray surface sensor used in the apparatus of the present invention has a change in detection sensitivity with a change in applied voltage. Any type of X-ray surface sensor is sufficient.

[0048]

As described above in detail, according to the X-ray diagnostic apparatus of the first aspect of the present invention, the voltage applied to the X-ray detecting element of the X-ray surface sensor during X-ray imaging is When the X-ray tube irradiates the subject with X-rays, it is changed according to the intensity level of the X-ray detection data output from the transmitted X-ray image detector, and the detection sensitivity of the X-ray detection element is automatically adjusted appropriately With this configuration, it is possible to prevent halation from appearing in the transmitted X-ray image, and at the same time, to improve the S / N ratio of the X-ray detection data and improve the image quality of the transmitted X-ray image. improves.

In the X-ray diagnostic apparatus according to the second aspect, the applied voltage of the X-ray detection element is given according to the X-ray detection data of each group of the X-ray detection elements divided into at least two groups. Detection sensitivity is more appropriate for the situation of each group, so it is possible to reliably prevent halation from occurring,
The S / N ratio is extremely improved, and the image quality of the transmitted X-ray image is further improved.

In the X-ray diagnostic apparatus according to the third aspect, since the change in the intensity level of the X-ray detection data due to the change in the applied voltage by the applied voltage control means is compensated, the influence of the change in the applied voltage affects the X-ray image. It does not appear. As a result, according to the invention of claim 3, an X-ray image with higher quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of an X-ray fluoroscopic apparatus according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of an applied voltage control system of the panel X-ray sensor according to the embodiment.

FIG. 3 is a plan view illustrating a basic configuration of a panel-type X-ray sensor according to an embodiment.

FIG. 4 is a partial cross-sectional view showing the internal configuration of the panel X-ray sensor of the embodiment.

FIG. 5 is a block diagram illustrating a circuit configuration around a panel-type X-ray sensor according to the embodiment.

FIG. 6 is a plan view showing a surface electrode forming surface of the panel X-ray sensor of the embodiment.

FIG. 7 is a graph showing the relationship between the incident X-ray dose and the intensity of X-ray detection data in the panel X-ray sensor of the example.

FIG. 8 is a graph showing the intensity of X-ray detection data of a panel-type X-ray sensor at the time of X-ray fluoroscopy, and a change with time of an applied voltage.

FIG. 9 is a graph showing the intensity of X-ray detection data of a panel-type X-ray sensor at the time of X-ray photography, and the change over time in applied voltage.

FIG. 10 is a flowchart showing the progress of applied voltage control during X-ray fluoroscopy.

FIG. 11 is a flowchart illustrating the progress of applied voltage control during X-ray photography.

FIG. 12 is a schematic diagram showing a main part configuration of a conventional X-ray fluoroscopic apparatus.

FIG. 13 is a schematic diagram showing a main part configuration of another conventional X-ray fluoroscopic apparatus.

FIG. 14 is a graph showing the relationship between the incident X-ray dose of a panel X-ray sensor of another conventional X-ray fluoroscopic apparatus and the intensity of X-ray detection data.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Top plate 2 ... X-ray tube 3 ... Flat panel type X-ray sensor 4 ... Signal collecting unit 6 ... Irradiation control unit 9 ... Imaging control unit 10 ... Data intensity compensating units 23a to 23d ... Divided electrodes 31 ... Applied voltage power supply unit 32: applied voltage control unit Ga to Gd: group M: subject XD: X-ray detection element

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G088 EE01 FF02 GG21 JJ05 KK32 KK40 LL15 4C093 AA05 CA06 CA35 EB13 EB17 EB18 EB30 FA32 FA45 FA59 FC17 FC18 4M118 AA10 AB01 BA05 CA14 CA22 CB05 FB10 FB10

Claims (3)

[Claims] An X-ray tube and a transmission X-ray image detector are disposed so as to face each other with a subject interposed therebetween, and the X-ray tube is transmitted along with X-ray irradiation of the subject by the X-ray tube. An X-ray diagnostic apparatus configured to obtain a transmission X-ray image based on X-ray detection data output from a line image detector,
An X-ray surface sensor in which a large number of X-ray detection elements are arranged vertically and horizontally as a line image detector, and the X-ray detection element of the X-ray surface sensor is used in accordance with the intensity level of the X-ray detection data. An X-ray diagnostic apparatus comprising: an applied voltage control unit that adjusts detection sensitivity by changing an applied voltage to be applied. 2. The X-ray diagnostic apparatus according to claim 1, wherein
The X-ray surface sensor has a configuration in which all the X-ray detecting elements are divided into at least two groups, and an applied voltage is independently applied to each group. X-ray diagnostic apparatus having a configuration that can be changed. 3. The X-ray diagnostic apparatus according to claim 1, further comprising a data intensity compensating means for compensating a change in the intensity level of the X-ray detection data accompanying a change in the applied voltage by the applied voltage control means. X-ray diagnostic equipment.