JPH0938071A - X-ray diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the shortage of X-ray dose by providing the device with an X-ray source drive means which drives the X-ray source so that X-ray exposure time per one image becomes that set by an exposure time setting means. SOLUTION: A control section 1 controls the power of an X-ray tube 3, controls the opening/closing of an X-ray diaphragm 4, and controls the drive of an X-ray detector 5. The control section 1 converts a detection signal from the X-ray detector 5 into digital data via an A/D converter 6 to memorize it in an image memory 7, and also converts the memorized digital data into an analog signal via a D/A converter 8 to display an X-ray image on a CRT display 9. A control section 2 is provided with a viewing angle setting section 2-1 which sets a viewing angles of the X-ray diaphragm 4 and the X-ray detector 5, and an irradiation time setting section 2-2 which sets the irradiation time of the X-ray tube 3, and the control section 2 drives the X-ray tube 3 so that an X-ray exposure time per one image becomes that set in advance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray generator that emits X-rays and an X-ray detecting element that detects the X-rays directly or through the light generated by the X-rays. The present invention relates to an X-ray diagnostic apparatus that includes a three-dimensional scanning type image detector, irradiates an object to be diagnosed with X-rays emitted from an X-ray generator, and detects an X-ray transmitted through the object to be diagnosed by an image detector.

[0002]

2. Description of the Related Art In an X-ray diagnostic apparatus that irradiates an object to be diagnosed with X-rays, detects the X-rays that have passed through the object to be diagnosed, and diagnoses the internal state of the object to be diagnosed, It is limited to pulses, and the X-rays that have passed through the object to be diagnosed are detected two-dimensionally (as an image) during this one pulse.
There is one that diagnoses an internal state of a diagnosis target between pulses.

Such an X-ray diagnostic apparatus is equipped with a two-dimensional scanning type image detector, and is adapted to continuously perform X-ray imaging in a pulsed manner a plurality of times. The two-dimensional scanning type image detector is configured, for example, as shown in FIG.

That is, as shown in FIG. 18, the X-ray detecting element forming the two-dimensional scanning type image detector includes a photodiode 101 for flowing a signal current according to the amount of incident light, and a signal current from the photodiode 101. A capacitor that stores electric charge by the following (hereinafter called storage capacitor) 1
02 and a TFT (thin film transistor) 103 for outputting the electric charge stored in the storage capacitor 102 as a current to the outside.

The connection point between the cathode terminal of the photodiode 101 and one terminal of the capacitor 102 is connected to a reverse bias power source (-Vn), and the photodiode 1
The connection point between the anode terminal of 01 and the other terminal of the storage capacitor 102 is connected to the input terminal of the TFT 103.

In the two-dimensional scanning image detector, the X-ray detecting elements are arranged in columns and lines in an array. Further, the gate terminal of the TFT 103 is commonly connected for each line and connected to each line output terminal of the gate driver 104.

From each line output terminal of the gate driver 104, a pulsed control signal is sequentially output in a time series, and the pulsed control signal simultaneously turns on the TFTs 103 on the same line. However, the TFTs 103 on different lines are sequentially turned on in time series.

The output terminal of the TFT 103 is commonly connected for each column, and a read-out amplifier (Read-out Amplifier) is provided.
ier) 105, capacitor 106, reset switch 10
Via the integrating circuit consisting of
Are connected to each input terminal.

The multiplexer 108 takes in the signals inputted to the respective input terminals during one pulse outputted from the respective line output terminals of the gate driver 104 one by one in a time series and outputs the signals. It is designed to output from the terminal.

Therefore, the pulse control signal output from each line output terminal of the gate driver 104 causes 1
When the line TFTs 103 are simultaneously turned on, the charges accumulated in the storage capacitor 102 pass through the TFTs 103 and are output. This current is converted into a voltage through an integrating circuit, and the current is converted by the multiplexer 108 one by one.
(One pixel for each line) is output. When the reading of one line is completed in this way, the reading of the next line is started. That is, one X-ray detecting element for each line (one pixel for each), like a scanning line of a television.
The detection signals are sequentially read and output as image data for one screen (video signal).

By the way, when a plurality of X-ray images are continuously picked up, VB is used as a signal for controlling the timing of reading the detection signal for one screen by the scanning as described above.
There is an L signal (vertical blanking signal). This is shown in FIG.
As shown in FIG. 9, a vertical blanking period B in which no reading is performed is provided during a vertical effective period A in which a detection signal for one screen is read from each X-ray detection element.

Therefore, as shown in the X-ray irradiation timing shown in the lower part of FIG. 19, X-ray irradiation is limited within the vertical blanking period B. This is to prevent the X-ray irradiation amount from being different between the X-ray detecting element read at the beginning of scanning and the X-ray detecting element read at the end of scanning when reading the detection signal for one screen.

[0013]

The dose of X-rays can be increased by increasing the tube current of an X-ray tube that generates X-rays, but there is an upper limit to the tube current that flows in the X-ray tube. Yes,
As a method of increasing the X-ray dose without increasing the tube current, there is a method of lengthening the irradiation time.

However, as described above, in the conventional X-ray diagnostic apparatus, the X-ray irradiation timing is limited within the vertical blanking period B of the VBL signal, so the X-ray irradiation time C is set to the vertical blanking period. Therefore, there is a problem that the X-ray irradiation dose is insufficient to obtain a sufficiently clear projected X-ray image when the subject has a large body thickness. Therefore, an object of the present invention is to provide an X-ray diagnostic apparatus capable of improving the shortage of X-ray irradiation dose.

[0015]

According to the first aspect of the present invention,
An X-ray image detector in which an X-ray source that emits X-rays toward a subject and a plurality of X-ray detection elements that convert the X-rays that have passed through the subject into charge signals and accumulate the charge signals are two-dimensionally arranged. A field-of-view setting means for setting a signal reading range of the X-ray detecting element group, a reading means for reading charge information accumulated in the X-ray detecting elements within the signal reading range, and an X-ray exposure time per image. And an exposure time setting means for changing the maximum value of the X-ray exposure time that can be set based on the signal read range.
X that drives the X-ray source so that the X-ray exposure time per image becomes the X-ray exposure time set by the exposure time setting means.
And a radiation source driving means.

According to a second aspect of the present invention, X is directed toward the subject.
X-ray detector that radiates X-rays, an X-ray image detector in which a plurality of X-ray detection elements that convert the X-rays that have passed through the subject into charge signals and accumulate the charge signals are arranged two-dimensionally, and an X-ray detection element. A field-of-view setting means for setting a signal reading range of the group and a vertical blanking signal indicating a vertical blanking period,
Sync signal generating means for changing the pulse width of the vertical blanking signal based on the width of the set signal reading range, and charge information accumulated in the X-ray detecting element within the signal reading range in synchronization with the vertical blanking signal. Reading means for reading
X-ray source driving means for driving the X-ray source so as to perform X-ray irradiation within the vertical blanking period based on the vertical blanking signal.

According to a third aspect of the present invention, in the invention according to any one of the first and second aspects, the X-ray image detector has a matrix shape having X-ray detection elements in rows and columns. The field-of-view setting means performs the signal reading range in at least one of row units and column units.

According to a fourth aspect of the present invention, X is directed toward the subject.
X-ray source that irradiates X-rays, an X-ray image detector in which a plurality of X-ray detection elements that convert and accumulate X-ray charge signals that have passed through a subject are arranged two-dimensionally, and X per image Exposure time setting means for setting the radiation exposure time, field-of-view setting means for setting the signal read range of the X-ray detection element group based on the set X-ray exposure time, and X-rays within the signal read range The reading means for reading out the charge information accumulated in the detecting element and the X-ray exposure time per image are set by the exposure time setting means.
X-ray source driving means for driving the X-ray source so that the radiation exposure time is reached.

According to a fifth aspect of the invention, in the invention according to any one of the first to fourth aspects, an X-ray diaphragm means for limiting an irradiation range of X-rays generated by the X-ray source. And an X-ray diaphragm control unit that controls the X-ray diaphragm unit so that the X-ray exposure range matches the set signal reading range.

According to a sixth aspect of the present invention, the invention according to any one of the first to fifth aspects is provided with display means for displaying the set signal read range.

According to a seventh aspect of the invention, in the invention according to any one of the first to sixth aspects, the X-ray detecting element is an X-ray / light converting means for converting X-rays into light. An optical / electrical converting means for converting light into an electric signal, and a capacitor for accumulating the electric signal output from the optical / electrical converting means as electric charge are provided.

According to an eighth aspect of the present invention, in the invention according to any one of the first to sixth aspects, the X-ray detection element is an X-ray / electric conversion means for converting an X-ray into an electric signal. And a capacitor for accumulating the electric signal output from the X-ray / electric conversion means as electric charge.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a circuit configuration of a main part of an X-ray diagnostic apparatus to which the invention is applied.

Although not shown, 1 is a CPU (central process
ssing unit), ROM (read only memory), RAM (ra
A control unit including an ndom access memory) and various interface circuits, and in particular, a timing control unit 1-1 for controlling timing of various peripheral devices described later.

The control unit 1 is based on an operation instruction from the operator's operation unit 2, and the X-ray tube 3 as an X-ray generation source.
Power is controlled to control the opening and closing of the X-ray diaphragm 4 which limits the irradiation direction of the X-rays emitted from the X-ray tube 3.
The object is irradiated from the X-ray tube 3 through the X-ray diaphragm 4,
Further, the drive of the X-ray detector 5 for detecting the transmitted X-rays is controlled.

Further, the control section 1 sends the detection signal (analog signal) from the X-ray detector 5 to A / D (analogue / digita).
l) It is converted into digital data through the conversion unit 6, this digital data is stored in the image memory 7, and the digital data stored in this image memory 7 is D / A (digital / analo).
(gue)) conversion unit 8 converts the analog signal again, and the CRT (cathode ray tube) display 9 displays the X-ray image by the analog signal.

The X-ray detector 5 is a two-dimensional scanning type image detector as described in the prior art (see FIGS. 17 and 18), which includes a photodiode and a capacitor (
The X-ray detection elements composed of storage capacitors and TFTs are arranged in a matrix, the TFTs of the X-ray detection elements in the line direction are controlled by the gate driver, and the detection signals output from the X-ray detection elements are read. It is sequentially read in the column direction by the multiplexer through the integrator circuit including the out amplifier, the storage capacitor, and the reset switch, and is output.

The timing control section 1-1 selects, for the X-ray detector 5, an amplifier reset signal for turning on the reset switch and a port (line) for outputting a pulse for reading the gate driver. It supplies the line select signal for selecting the port and the column select signal for selecting the port (column) that takes in the signal of the multiplexer. Further, for the A / D conversion unit 6 and the D / A conversion unit 8, a timing signal for conversion (sampling signal
) Is supplied to the image memory 7, and a read / write timing signal for controlling data read / write is supplied to the image memory 7.

Further, the operating section 2 has a field setting section 2-1 for setting fields of view of the X-ray diaphragm 4 and the X-ray detector 5, and an X-ray irradiation time (irradiation pulse width) in the X-ray tube 3. An irradiation time setting unit 2-2 for setting the above) is provided.

In the first embodiment having such a configuration, the image pickup conditions are set according to the flow of processing as shown in FIG. 2, and the actual image pickup is performed based on the set image pickup conditions.

FIG. 2 is a diagram showing a flow of the image pickup condition setting process performed by the control unit 1 before the image pickup operation. First, step 1
As the processing of (ST1), the irradiation time setting unit 2 of the operation unit 2 is
-2 is used to judge whether or not there is an X-ray pulse width designation input. If it is determined that there is no X-ray pulse width designation input, as the processing of step 2 (ST2), the reading field designation input (number of reading lines and reading start line Judge whether there is a designated input). If it is determined that the reading line has not been designated, it is determined in step 3 (ST3) whether or not there is an input from the operation unit 2 that sets the entire field of view as the reading range. Here, if it is determined that there is no input for reading the entire visual field, the process returns to step 1 described above.

If it is judged in the above-mentioned step 1 that the X-ray pulse width has been designated, step 4 (
In step ST4), the designated and input X-ray pulse width is set as the pulse width for actually energizing the X-ray tube 3.

As the processing of step 5 (ST5), the number of possible reading lines is calculated based on this X-ray pulse width, and a display showing the number of possible reading lines obtained by this calculation is displayed on the CRT display 9. Step 6 (ST6
As a process of (1), the visual field setting unit 2-1 is in a standby state until the reading line is designated.

In the process of step 6, if there is a designation input of a reading line, as the process of step 7 (ST7),
This designated input line (the number of reading lines from the designated input reading start line) is set as a reading line. When the setting of the reading line is completed, the imaging condition setting process is completed.

If it is determined in the above-mentioned step 2 that there is a designation input of the reading line, step 8 (S
In the process of T8), the designated and input line is set as the reading line. Next, as the processing of step 9 (ST9), the maximum value of the X-ray pulse width is calculated and set based on the set reading line, and step 1 described later is performed.
The process proceeds to 0 (ST10).

When it is determined in the above-described step 3 that there is an input with the entire visual field as the reading range, all the lines are set as the reading lines as the processing of step 11 (ST11). Next, as the processing of step 12 (ST12), the maximum value of the X-ray pulse width is set to the normal value, and the processing proceeds to the next step 10.

The processing of step 10 is performed for the set X
The maximum value of the line pulse width is displayed on the CRT display 9, and a display requesting the designated input of the X-ray pulse width (X-ray irradiation time) is performed.

Next, as the processing of step 13 (ST13), the irradiation time setting unit 2-2 enters a standby state until the X-ray pulse width designation input is made. When the designated input of the X-ray pulse width is performed, the designated X-ray pulse width is actually input to the X-ray tube 3 as the processing of step 14 (ST14).
Set as the pulse width for energizing the. When the setting image of the X-ray pulse width is completed, the imaging condition setting process is completed.

For example, as shown in FIG. 3, from the top ((x + 1)
) Th line as the reading start line, the total number of lines n
If the number of lines (n−x) obtained by subtracting the number of lines x from is set as the number of read lines, the area D from the (x + 1) th line to the nth line becomes the read line.

At this time, the new VBL signal (vertical blanking signal changed by limiting the number of read lines) and the X-ray irradiation timing are as shown in FIG. The vertical blanking period E is extended from the conventional vertical blanking period B by the period F for reading the 0th line to the xth line. Therefore, the vertical effective period G is obtained by removing the period F from the conventional vertical effective period (A).

Therefore, the irradiation time of the X-ray irradiation timing
The (X-ray pulse) H is limited within the period K excluding the reset period J provided in the first part of the vertical blanking period E. That is, the maximum value of the irradiation time H is the period K.

The reset period J is generated by light incident on the X-ray detecting element (pixel) on the line which is not read due to scattered rays, Behring Claire (X-ray scattering by the scintillator), or the X-ray detecting element itself. The charges accumulated under the influence of the dark current and the charges accumulated under the influence of the dark current in the pixels of the read line are provided at appropriate timing. The reset period J is
It may be performed before the X-ray irradiation. It may also be performed after the X-ray irradiation.

In the reset period J, the pulse is supplied from the gate driver to all the target lines simultaneously or into each group, and the pulse is supplied for reading. Of course, all the read data are treated as invalid.

As shown in FIG. 5, from the top (y + 1)
If the number of lines z (<n−y) smaller than the number of lines (n−y) obtained by subtracting the number of lines y from the total number of lines n is set as the number of reading lines, the (y + 1) th line is set as the reading start line. The area D from the line to the (y + z) th line is the read line.

At this time, the new VBL signal and the X-ray irradiation timing are as shown in FIG. The symbols (alphabets) in FIG. 6 are denoted by the same symbols for the periods having the same contents as in FIG. 4, and description thereof will be omitted. Period F1
Is originally a period for reading the 0th line to the yth line, and the period F2 is a period for originally reading the (y + z + 1) th line to the nth line.

Further, for example, when the X-ray irradiation time is first determined from the body thickness of the subject, this X-ray irradiation time is set first, and based on the set irradiation time (X-ray pulse width) Then, the vertical blanking period is calculated, the vertical effective period G is calculated, and the finally possible number of read lines is calculated and displayed.

If the operator sets the reading lines below the displayed number of possible reading lines, the subject is irradiated with X-rays at a desired irradiation time, and reading is performed on the set reading lines.

Further, in the first embodiment, the reading line can be arbitrarily set. However, for example, in a normal operation in which the visual field is all lines (visual field 100%), FIG. As shown in Fig. 7, the first visual field limiting operation (visual field 90%) that limits the visual field to 90% of all lines, and the second visual field limitation that limits the visual field to 70% of all lines as shown in Fig. 7 (b). Operation, as shown in FIG. 7C, a third visual field limiting operation for limiting the visual field to 50% of all lines may be set in advance, and these operations may be selectively designated by switching. is there. The VBL signal in each operation is as shown in FIG. Of course, the readable area D is set at the center in FIG. 7, but the position can be freely moved within the range of the visual field.

As described above, according to the first embodiment, by limiting the number of reading lines, the reading time for the lines that are not subject to reading due to the limitation is reduced in the vertical valid period of the VBL signal. It is possible to increase the X-ray irradiation time by adding the reduced time to the vertical blanking period. Also, when the X-ray irradiation time is set to be long, the number of possible reading lines is calculated and displayed, and by requesting the setting of reading lines,
X-ray imaging can be performed with a desired irradiation time. That is, the shortage of the X-ray irradiation amount can be improved.

A second embodiment of the present invention will be described with reference to FIGS. 9 to 11. The circuit configuration of the main part of the X-ray diagnostic apparatus according to the second embodiment is almost the same as that of the first embodiment described above, and therefore, the same members are designated by the same reference numerals and the description thereof will be omitted.

In this X-ray diagnostic apparatus, imaging conditions are set according to the flow of processing as shown in FIG. 9, and actual imaging is performed based on the set imaging conditions. FIG.
FIG. 4 is a diagram showing a flow of an imaging condition process performed by the control unit 1 before an imaging operation.

First, as the processing of step 21 (ST21), it is determined whether or not the irradiation time setting unit 2-2 of the operation unit 2 has designated input of the X-ray pulse width. If it is determined that the X-ray pulse width has not been designated, step 22 (
In the processing of ST22), it is determined whether or not there is a reading range designation input (number of reading lines, reading start line and reading start row, reading end row designation input) by the visual field setting section 2-1 of the operation section 2. . Here, if it is determined that there is no designation input of the reading range, as a process of step 23 (ST23), it is determined whether or not there is an input with the operating unit 2 as the reading range. If it is determined that there is no input for reading the entire visual field, the process returns to step 21.

In the processing of step 21 described above, X
If it is judged that there is a designated input of the line pulse width, step 2
4 (ST24), the designated and input X-ray pulse width is set as the pulse width for actually energizing the X-ray tube 3.

As the processing of step 25 (ST25),
Based on this X-ray pulse width, the number of possible reading lines and the number of possible reading rows are calculated, and the standard reading range showing the number of possible reading lines and the number of reading rows obtained by this calculation is set to the CRT.
Display on the screen of the display 9. Step 26 (ST
26), the visual field setting unit 2-1 enters a standby state until the reading range is designated.

If the reading range is designated in step 26, the designated line is read (the designated number of reading lines from the designated reading start line) in step 27 (ST27). Is set as a reading line, and the designated and input column (the designated input-starting column to the reading end column) is set as a reading line column.

When the setting of the reading range (reading line and reading line) is completed, as a process of step 28 (ST28), a display showing the set reading range is displayed on the screen of the CRT display 9 and the imaging condition is set. The setting process ends.

If it is judged in the processing of step 22 that the reading range has been designated, step 29 (
In the process of ST29), the designated and input line is set as a reading line, and the designated and input line is set as a reading line column.

When the setting of the reading range is completed, the display of the set reading range is displayed on the screen of the CRT display 9 as the process of step 30 (ST30). Next, as the process of step 31 (ST31), the maximum value of the X-ray pulse width is calculated and set based on the set reading range, and the process proceeds to step 32 (ST32) described later. ing.

If it is determined in the above-described step 23 that there is an input with the entire visual field as the reading range, all the lines are set as the reading line and all the columns are set as the reading line in the processing of step 33 (ST33). Set as. next,
As the processing of step 34 (ST34), the maximum value of the X-ray pulse width is set to a normal value, and the process proceeds to the next step 32.

The process of step 32 is performed with the set X
The maximum value of the line pulse width is displayed on the CRT display 9, and a display requesting the designated input of the X-ray pulse width (X-ray irradiation time) is performed.

Next, as the processing of step 35 (ST35), the irradiation time setting section 2-2 enters a standby state until an X-ray pulse width designation input is made. When the designated input of the X-ray pulse width is performed, the designated X-ray pulse width is actually used as the processing of step 36 (ST36).
Set as the pulse width for energizing the. When the setting of the X-ray pulse width is completed, the imaging condition setting process is completed.

For example, as shown in FIG. 10, from the top (y +
If the number of lines z (<n−y) smaller than the number of lines (n−y) obtained by subtracting the number of lines y from the total number of lines n is set as the number of read lines with the 1) th line as the reading start line, (y + 1 The line from the) th line to the (y + z) th line is the read line. Also, from the left (s + 1
When the) th column (pixel) is set as the reading start column and the (s + t) th column from the left is set as the reading end column, the (s + 1) th column to the (s + t) th column are the reading columns. An area D surrounded by the reading line and reading row is the reading range.

FIG. 11 is a diagram showing a conventional HBL signal (horizontal blanking signal) and a new HBL signal when the reading range is set as described above. This HBL signal (new HBL signal) is the vertical effective period G (A) of the VBL signal.
VBL signal vertical effective period G (A)
Is a period for reading each line of one captured image, while the horizontal effective period L (new HB
The horizontal effective period M 1 of the L signal is a period for reading pixels for the one line.

That is, the horizontal valid period L is obtained by multiplying the time required to read one pixel by the number of pixels for one line. The horizontal valid period L is multiplied by the number of lines of one captured image. The thing is the vertical effective period A.

When the reading range is set as described above, the horizontal effective period is obtained by multiplying the time required to read one pixel by the number of pixels set as the reading column of the pixels for one line. Then, the horizontal effective period M is multiplied by the number of lines set as the reading line of the lines of one captured image to become the vertical effective period.

Therefore, even if all the lines are set as the reading lines, if the reading range is limited by columns (pixels), the horizontal effective period is shortened and the vertical effective period is shortened accordingly. It will be an extension of the period. As a result, the maximum value of the X-ray pulse width becomes long.

As described above, according to the second embodiment, the effect of the first embodiment described above can be obtained, and the reading range can be limited even in the columns, so that the reading efficiency can be improved. The X-ray irradiation time can be lengthened. That is, it is possible to more efficiently improve the shortage of the X-ray irradiation amount.

Furthermore, by displaying the set reading range on the screen of the CRT display 9, it is possible to easily confirm the set reading range, so that the operability of setting the reading range can be improved. Make sure the desired part (
For example, it is possible to perform X-ray imaging of a diseased part, an inspection tissue).

A third embodiment of the present invention will be described with reference to FIGS. The circuit configuration of the main part of the X-ray diagnostic apparatus according to the third embodiment is almost the same as that of the first embodiment described above, and therefore, the same members are designated by the same reference numerals and the description thereof will be omitted.

In particular, in the third embodiment, a visible light source is built in the X-ray tube 3 so that the X-ray irradiation portion can be visually confirmed. This X-ray diagnostic device
Imaging conditions are set in accordance with the flow of processing as shown in FIG. 12, and actual imaging is performed based on the set imaging conditions. The image capturing condition setting process shown in FIG. 12 and the image capturing condition setting process in the above-described second embodiment (
9)) is different only in the part described below.

That is, the processing of setting the reading range (specified line setting, specified column setting) in step 27 (ST27) and step 29 (ST29) and step 28 (ST28)
) And the reading range screen display process of step 30 (ST30), the following two processes are inserted in order.

First, as the processing of step 41 (ST41) and step 42 (ST42), based on the reading range set in step 27 and step 29, X-rays are not irradiated outside the set reading range. To
Adjust the X-ray diaphragm 4.

For example, if the opening of the X-ray diaphragm 4 is adjusted,
As shown in FIG. 13A and FIG. 13B, the X-ray irradiation range (effective visual field) is adjusted. An irradiation range M is formed for the opening L of FIG. 13A, and an irradiation range P narrower than the irradiation range M is formed for the opening N narrowed down from the opening L.
Is formed. Therefore, here, the opening degree of the X-ray diaphragm 4 is adjusted so that the reading field and the irradiation range coincide with each other.
The subject is located between the X-ray diaphragm 4 and the X-ray detector 5.

Although X-rays are not visible, in the third embodiment, since the visible light source 11 is built in the X-ray tube 3, the X-ray irradiation range is shown in FIG. As described above, since the irradiation range of the (visible) light from the visible light source 11 matches, it can be visually confirmed.

Next, as the processing of step 43 (ST43) and step 44 (ST44), the visible light source 11 built in the X-ray tube 3 is turned on. In addition, step 33 (
ST33) processing for setting all lines and all columns and step 34
Between the process of setting the maximum value of the X-ray pulse width of (ST34) to the normal value, the following two processes are inserted in order.

First, as the processing of step 45 (ST45), the X-ray diaphragm 4 is adjusted to the normal opening degree. Next, as the process of step 46 (ST46), the visible light source 11 is turned on.

Therefore, when the processing of setting the reading range is performed, the X-ray diaphragm 4 is adjusted according to the set reading range. That is, X-rays are not emitted outside the reading range. Further, the visible light source 11 is turned on, and the irradiation range of X-rays at this time, that is, the reading range is indicated by irradiation of visible light on the detection surface (X-ray receiving surface) of the X-ray detector 5.

By the way, FIG. 14 shows an example of displaying the set reading range on the screen of the CRT display 9 in the reading range screen display processing of step 28 (ST28) and step 30 (ST30). Here, CRT
A window 12 is opened on a part of the screen of the display 9 to display the reading range.

As described above, according to the third embodiment, the same effect as that of the second embodiment can be obtained, and further, the X-ray diaphragm 4 is adjusted in accordance with the setting of the reading range. Thus, it is possible to prevent the irradiation of X-rays outside the set reading range.

Therefore, it is possible to avoid unnecessary exposure of the subject to X-rays and to reduce the burden on the subject (examiner, patient). Also, the X-ray tube 3
Since the visible light source 11 is built in, the irradiation range of X-rays that matches the set reading range can be directly indicated on the detection surface (subject) of the X-ray detector 5 by the light from the visible light source 11. The operability of setting the reading range can be improved, and X-ray imaging of a desired site (for example, a diseased site or a test tissue) can be more reliably performed.

Regarding the display of the reading range or the X-ray irradiation range, other than the method of using the visible light source 11 and the method of displaying on the screen of the CRT display 9 as shown in FIG. Back side of detector 5 (
A plurality of light emitting diodes arranged corresponding to some typical reading ranges are provided on the surface (opposite to the detection surface), and when the reading range is set, the light emitting diodes arranged at the corresponding positions. There is also a method of displaying the reading range by illuminating. Further, as shown in FIG. 16, the detection surface of the X-ray detector 5
There is also a method of performing printing showing a typical reading range on the (X-ray receiving surface). As described above, the present invention is not limited to the embodiments described above in detail, and may be modified without departing from the gist of the invention.

[0082]

As described above in detail, according to the present invention,
By limiting the reading range of the X-ray detector composed of a plurality of X-ray detection elements, the proportion of the pulse width of the vertical blanking period in the vertical blanking signal can be increased to increase the X-ray irradiation pulse width. It is possible to provide an X-ray diagnostic apparatus capable of improving the shortage of the X-ray irradiation amount by increasing the maximum value.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of essential parts of an X-ray diagnostic apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a flow of an imaging condition setting process performed before an imaging operation in the X-ray diagnostic apparatus according to the same embodiment.

FIG. 3 is a diagram showing a first example of setting a reading line in the X-ray diagnostic apparatus according to the same embodiment.

FIG. 4 is a diagram showing a vertical blanking signal and X-ray irradiation timing corresponding to the first example of FIG. 3 in the X-ray diagnostic apparatus of the embodiment.

FIG. 5 is a diagram showing a second example of setting a reading line in the X-ray diagnostic apparatus according to the same embodiment.

FIG. 6 is a diagram showing a vertical blanking signal and X-ray irradiation timing corresponding to the second example of FIG. 5 in the X-ray diagnostic apparatus of the embodiment.

FIG. 7 is a diagram showing an example of three settings of reading lines in the X-ray diagnostic apparatus according to the same embodiment.

FIG. 8 is a diagram showing a change in timing of a vertical blanking signal corresponding to an example of three settings of the read line in FIG. 7 in the X-ray diagnostic apparatus according to the same embodiment.

FIG. 9 is a diagram showing a flow of imaging condition setting processing performed before an imaging operation in the X-ray diagnostic apparatus according to the second embodiment of the present invention.

FIG. 10 is a diagram showing an example of setting a reading range in the X-ray diagnostic apparatus according to the same embodiment.

FIG. 11 is a schematic view of the X-ray diagnostic apparatus according to the same embodiment (
FIG. 11 is a diagram showing a horizontal blanking signal (HBL) of (conventional) and a horizontal blanking signal (new HBL) field timing corresponding to the example of FIG. 10.

FIG. 12 is a diagram showing a flow of imaging condition setting processing performed before an imaging operation in the X-ray diagnostic apparatus according to the third embodiment of the present invention.

FIG. 13 is a perspective view showing a state of an X-ray diaphragm for setting a reading range of the X-ray diagnostic apparatus according to the same embodiment.

FIG. 14 is a diagram showing a reading range displayed on a part of the screen of the CRT display of the X-ray diagnostic apparatus according to the same embodiment.

FIG. 15 is a perspective view showing a first example of a display method of a reading range setting state (effective visual field) of the X-ray diagnostic apparatus of the embodiment.

FIG. 16 is a diagram showing a second example showing a method of displaying the setting state (effective visual field) of the reading range of the X-ray diagnostic apparatus according to the same embodiment.

FIG. 17 is a block diagram including a partial circuit showing a configuration of a conventional two-dimensional scanning image detector.

FIG. 18 is a circuit diagram showing an X-ray detection element forming the two-dimensional scanning type image detector of the conventional example.

FIG. 19 is a diagram showing a vertical blanking signal (VBL signal) and an X-ray irradiation timing in the two-dimensional scanning image detector of the conventional example.

[Explanation of Codes] 1 ... Control unit, 1-1 ... Timing control unit, 2 ... Operation unit, 2-1 ... View setting unit, 2-2 ... Irradiation time setting unit, 3 ... X-ray tube, 4 ... X-ray Aperture, 5 ... X-ray detector, 9 ... CRT display, 11 ... Visible light source.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Tsukamoto 1385-1 Shimoishigami, Otawara, Tochigi Stock Company Toshiba Nasu factory (72) Inventor Shinichi Yamada 1385-1 Shimoishi, Otawara, Tochigi Inside the Toshiba Nasu Factory (72) Inventor Toru Saino 1385-1 Shimoishigami, Otawara City, Tochigi Prefecture Inside the Toshiba Nasu Factory (72) Inventor Takayuki Tomisaki 1385-1 Shimoishigami, Otawara City, Tochigi Prefecture Toshiba Nasu Factory (72) Inventor Manabu Tanaka 1385-1 Shimoishigami, Otawara City, Tochigi Prefecture Toshiba Nasu Factory (72) Inventor Seiichiro Nagai 1385-1 Shimoishi, Otawara City, Tochigi Prefecture Toshiba Medical Engineering Co., Ltd. In the company

Claims (8)

[Claims] 1. A two-dimensional array of an X-ray source that irradiates an object with X-rays, and a plurality of X-ray detection elements that convert the X-rays that have passed through the object into charge signals and accumulate the charge signals. An X-ray image detector, field-of-view setting means for setting a signal reading range of the X-ray detecting element group, and reading means for reading charge information accumulated in the X-ray detecting element within the signal reading range, An X-ray exposure time for one image is set, and an exposure time setting means for changing the maximum value of the X-ray exposure time that can be set based on the signal reading range, and an X-ray per image An X-ray diagnostic apparatus comprising: an X-ray source drive unit that drives the X-ray source so that the exposure time becomes the X-ray exposure time set by the exposure time setting unit. 2. An X-ray source that irradiates X-rays toward a subject, and a plurality of X-ray detection elements that convert the X-rays that have passed through the subject into charge signals and accumulate the charge signals in a two-dimensional array. The X-ray image detector, the visual field setting means for setting the signal read range of the X-ray detection element group, and the vertical blanking signal indicating the vertical blanking period are generated, and the set signal read range is set. Sync signal generating means for changing the pulse width of the vertical blanking signal based on the width of the vertical blanking signal, and reading the charge information accumulated in the X-ray detection element within the signal reading range in synchronization with the vertical blanking signal. An X-ray source driving unit that drives the X-ray source so as to perform X-ray irradiation within the vertical blanking period based on the vertical blanking signal. Line diagnostic device 3. The X-ray image detector has X-ray detection elements arranged in a matrix having rows and columns, and the field-of-view setting means sets the signal reading range in at least one of row units or column units. The X-ray diagnostic apparatus according to claim 1, which is performed. 4. An X-ray source that irradiates an object with X-rays, and a plurality of X-ray detection elements that convert and store X-ray charge signals that have passed through the object are arranged two-dimensionally. An X-ray image detector, an exposure time setting means for setting an X-ray exposure time per image, and a signal read range of the X-ray detection element group based on the set X-ray exposure time. Field-of-view setting means for setting, reading means for reading charge information accumulated in the X-ray detection element within the signal reading range, and X-ray exposure time per image is set by the exposure time setting means. An X-ray diagnostic apparatus comprising: an X-ray source driving unit that drives the X-ray source so that the X-ray exposure time is kept constant. 5. The X-ray diaphragm means for limiting an irradiation range of X-rays generated by the X-ray source, and the X-ray irradiation range so that the X-ray irradiation range coincides with the set signal reading range. The X-ray diagnostic apparatus according to claim 1, further comprising: an X-ray diaphragm control unit that controls the line diaphragm unit. 6. The X-ray diagnostic apparatus according to claim 1, further comprising display means for displaying the set signal readout range. 7. The X-ray detection element, an X-ray / optical conversion means for converting X-rays into light, an optical / electrical conversion means for converting the light into an electric signal, and an output from the optical / electrical conversion means. The X-ray diagnostic apparatus according to any one of claims 1 to 6, further comprising a capacitor that stores the generated electric signal as an electric charge. 8. The X-ray detection element includes X-ray / electrical conversion means for converting X-rays into electric signals, and a capacitor for accumulating the electric signals output from the X-ray / electrical conversion means as electric charges. The X-ray diagnostic apparatus according to any one of claims 1 to 6, wherein