JPS635880B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-ray diagnostic apparatus that can obtain an X-ray photograph of a target imaging site most suitable for diagnosis in X-ray contrast imaging of, for example, a digestive organ.

BACKGROUND ART Contrast media such as barium are generally used in X-ray imaging of the digestive organs, such as the stomach or esophagus. By the way, when photographing the stomach, the contrast medium remains in the stomach for a while, so there are almost no restrictions on the timing of X-ray exposure, whereas when photographing the esophagus, the contrast medium stays in the stomach for a while. Since it is moving towards the
The timing of radiation exposure must be set.
In this regard, conventionally, the timing of X-ray exposure was determined based on the operator's intuition or experience immediately after the subject swallowed the contrast medium in his or her mouth. For this reason, a large number of X-ray photographs are taken which have no diagnostic value, and this has the disadvantage of subjecting the patient to unnecessary X-ray exposure. A method using a monitor of an X-ray television apparatus has also been proposed in order to eliminate such adverse effects. That is, one predetermined horizontal scanning line on the monitor is selected, all or part of the video signal on the scanning line is monitored, and the point where the video signal becomes below a predetermined level due to passage of the contrast agent is automatically detected. This is a method in which X-ray imaging is started based on this detection. However, this method has the following drawbacks: (1) The video signal level of the skeleton, such as the ribs or spinal cord seen through the esophagus, is close to that of the contrast agent, so it may not be possible to distinguish between the two depending on the viewing conditions; (2) ) If the fluoroscopic conditions (fluoroscopic tube voltage, fluoroscopic tube current) are changed during fluoroscopy, the level of the entire video signal will rise or fall due to the change in brightness, and will fall below the predetermined level regardless of the presence or absence of a contrast agent. and (3) the video signal level may drop due to unnecessary movements of the subject. This has caused problems such as inducing unnecessary X-ray exposure and missing the precious X-ray imaging timing.

The present invention has been made in view of the above circumstances, and when performing X-ray contrast imaging, selects a predetermined horizontal scanning line on a fluoroscopic monitor and sequentially and alternately transmits only the video signal on the scanning line using two integrators. and further calculate the difference between the output signals of the integrator to form a video difference signal, and detect the time point at which the video difference signal changes to a predetermined value or more when the contrast agent passes over the scanning line; It is an object of the present invention to provide an X-ray diagnostic apparatus that can accurately obtain an optimal X-ray photograph for diagnosis by starting X-ray photography based on this.

The present invention will be specifically explained below using Examples.

FIG. 1 is a block diagram showing one embodiment of the apparatus of the present invention. 11 in the figure is an X-ray tube device,
SX is emitted and reaches an image intensifier 15 via a subject 12 and a grid 13 arranged in the direction of the radiation. An X-ray film 14 will be placed between the grid 13 and the image intensifier 15. During fluoroscopy, this X-ray film 14 is located at a remote position A, and immediately before imaging, it is moved to an imaging position B. It is possible to move and then return to position A again after the photographing time has elapsed. 16 is an optical system consisting of a lens, a distributor, etc., and 17 is an X-ray television camera device. The output video signal S1 of the television camera device 17 is transferred to the camera control device 18 and the video signal gate circuit 22. This camera control device 18 includes a drive pulse generation circuit 181
and a video signal processing circuit 182,
A vertical synchronization signal S is output from the drive pulse generation circuit 181.
2 and a horizontal synchronizing signal S3 are generated. 20 is a pulse control circuit which receives the vertical synchronizing signal S2 and horizontal synchronizing signal S3 as input, and is a momentary control circuit which sets this embodiment device into an active state when a switch is pressed, and which is released from an active state when the switch is released. The signal S4 from the set switch 21 is input, and the first
Integral command signal S5, second integral command signal S
6. A first integral reset signal S7 and a second integral reset signal S8 are output to the video signal gate circuit 22, and a command strobe signal S9 is output to a command generation circuit 23, which will be described later. The video signal gate circuit 22 receives the video difference signal S1.
0 is generated and transferred to the command generation circuit 23. The command generation circuit 23 determines the X-ray imaging timing in relation to the signals S4, S9, and S10, and generates the X-ray imaging start command signal S1.
1 to the X-ray control device 24. The X-ray control device 24 connects the X-ray tube device 1 via the high voltage generator 25.
Drive 1. Note that 19 is a monitor.

An example of a specific configuration of the pulse control circuit 20 is shown in FIG. Here, a case is shown in which the interlaced scanning method used by most X-ray television apparatuses is applied. 2002 is a JK flip-flop circuit for sampling a predetermined horizontal scanning line, and a clock terminal (CK)
vertical synchronization signal S2 via gate circuit 2001.
is applied, and a vertical synchronization divided signal S201 is output from the output terminal (Q). 2003 is for sequentially and alternately distributing the selected scanning lines for each frame.
This is a JK flip-flop circuit, in which the vertical synchronization divided signal S201 is applied to the clock terminal (CK), the first vertical gate signal S202 is applied from one output terminal (Q), and the second vertical gate signal S202 is applied from the other output terminal ( Q ). Each outputs a gate signal S203. On the other hand, the horizontal synchronization signal S3 is applied to the shift register 2014 via the gate circuit 2012. This shift register 2014 is connected to the gate circuit 2001.
A gate circuit 2004 has two inputs: the output of the flip-flop circuit 2002 for horizontal scanning line sampling, and a vertically synchronized frequency-divided signal based on the inverted output of the flip-flop circuit 2002.
and the set signal S4 from the momentary type set switch 21 are set by the output of the gate circuit 2005, which outputs a plurality of signals S4.
2014 is output. These multiple signals S2014
Each signal rises when the horizontal synchronizing signal S3 changes from a high level to a low level, and then when the horizontal synchronizing signal S3 changes to a high level and then changes from a high level to a low level again, the signal S2014 falls. The shift register 2014 has a function as a counter, so to speak, and when the horizontal synchronization signal S3 is input to the shift register 2014 via the gate circuit 2012, the shift register 2014 is changed by the amount by which this horizontal synchronization signal S3 is input.
Signal S2014 is output from only one of the output terminals of. This signal S2014 is selected by the operation of the rotary switch 2015 and is output as the horizontal gate signal S204. That is, the fifth
As shown in the figure, after the shift register 2014 is reset, when a horizontal synchronization signal S3 corresponding to, for example, the fifth horizontal scanning line is input to the shift register 2014, the shift register 2014 is reset.
From then on, a signal S2 corresponding to this fifth horizontal scanning line is generated.
014 is output. Then, by the operation of the rotary switch 2015, this fifth signal S201
4 is selected, and the same pulse width T as signal S2014 is selected.
-C is output as a horizontal gate signal S204. Then, the gate signals S202, S2
03 and S204 are mutually combined and input to two-input gate circuits 2006 and 2007, and furthermore, the outputs of these gate circuits 2006 and 2007 are mutually combined with the horizontal synchronizing signal S3 obtained via the gate circuit 2012 and gate circuit 2013. The signals are combined and input to two-input gate circuits 2010 and 2011. A first integral command signal S5 having the same pulse width T-C as the horizontal gate signal S204 is obtained from the gate circuit 2008 to which the output of the gate circuit 2006 is applied, and from the gate circuit 2009 to which the output of the gate circuit 2007 is applied. A second integral command signal S6 having the same pulse width T-C as the horizontal gate signal S204 is obtained. Further, from the gate circuits 2010 and 2011, a first integral reset signal S7 and a second integral reset signal S8 having a pulse width T-r corresponding to one horizontal retrace period of the horizontal synchronizing signal S3 are obtained. Also, 201
Reference numeral 6 denotes a one-shot circuit, which operates at the trailing edge of the horizontal gate signal S204 and outputs a command strobe signal S9.

Next, an example of a specific configuration of the video signal gate circuit 22 is shown in FIG. In the figure, 1 is the first integrator, which includes an operational amplifier 2201 and a capacitor C220.
1. Consists of resistors R2201 and R2202. 2 is a second integrator, which is an operational amplifier 2202;
Capacitor C2202, resistor R2203, R22
04. 3 is a subtracter, which includes an operational amplifier 2203, resistors R2205, R2206,
It is composed of R2207 and R2208. 4 is an absolute value circuit, which includes an operational amplifier 2204 and a resistor R.
2209, R2210, diode D2201,
It is configured by D2202. 5 is an analog switch group, which includes switches 2205a and 2206a provided in the application path of the video signal S1 and switches 2207a and 2207a provided in the integrators 1 and 2.
208a. That is, for example, 2205 is the first
An analog switch 2206 conducts its path 2205a only when the integral command signal S5 is active, 2206 conducts its path 2206a for the second integral command signal S6, and 2207 and 2208 similarly conduct the first integral reset signal S7 and Second integral reset signal S8
This is an analog switch that makes the paths 2207a and 2208a conductive. Therefore, in integrators 1 and 2, analog switch paths 2205a and 2
The video signal is integrated only when 206a is conductive, and the output signal S22 of each integrator 1 and 2 is integrated when analog switch paths 2207a and 2208a are conductive.
1 and S222 are set to zero.

Next, an example of a specific configuration of the command generation circuit 23 is shown in FIG. 6 is a comparator, which includes an operational amplifier 2301, resistors R2301, R2302, R
2303, diode D2301, power supply 2302
Consisted of. The output signal of this comparator 6 is
Resistor R2304, R2305, transistor 23
The signal is level-converted by a level conversion circuit consisting of 03 and becomes a comparison detection signal S231. The command strobe signal S9 is input to the gate circuit 2305 together with the signal S231 via the gate circuit 2304, and becomes a signal S232. 2306 is a JK flip-flop circuit, and the clock terminal (CK)
The signal S232 is sent to the preset terminal (PS).
The set signal S4 is applied to each of the terminals, and a resistor R2 is applied to the control terminal (CR).
306, and is applied via output gate circuits 2308 and 2309 of an integrating circuit consisting of a capacitor C2301. Therefore, this flip-flop circuit 2306 is in a reset state when the power is turned on.
When the set signal S4 is applied, a signal S233 that enters the preset state is output. This output S233
An X-ray imaging start command signal S1 is sent from the gate circuit 2307 to which the output S232 and the output S232 are both input.
1 is output.

Next, the operation of the embodiment apparatus having the above configuration will be explained with reference to the timing chart shown in FIG. First, when taking an X-ray image of the target diagnosis site, a fluoroscopic image of the target diagnosis site of the subject 12 is created by the grid 13 and the image intensity using the X-ray SX (waveform shown in FIG. Fire 1
5. It is assumed that the image is input to the X-ray television camera device 17 via the optical system 16. At this time, the video signal S1, which is the output signal of the X-ray television camera device 17, is transmitted to the camera control device 18.
A transparent image is displayed on the monitor 19 via the. In this state, in order to select a predetermined horizontal scanning line on the monitor 19, the X-ray television camera device 1
7. Vertical synchronization signal S2 generated by the drive pulse generation circuit 181 in the camera control device 18 that controls the display timing of the monitor 19;
The horizontal synchronization signal S3 is sent to the pulse control circuit 20
and at the same time the pulse control circuit 20
The rotary switch 2015 inside is manually set to correspond to the scanning line. Then, the pulse control circuit 20 operates the gate circuit 2001 and the flip-flop circuit 2 based on the vertical synchronization signal S2.
002 generates a vertical synchronization frequency divided signal S201 (waveform shown in FIG. 5c) that selects every other predetermined field, and this is further frequency-divided by a flip-flop circuit 2003 to generate a first vertical gate signal S202 and a second vertical gate signal S202. A gate signal S203 is formed (waveforms d and e in the figure). On the other hand, in order to identify the number of horizontal scanning lines up to a predetermined horizontal scanning position for each field, the gate circuit 2012, shift register 2014, and rotary switch 2015 are operated based on the horizontal synchronization signal S3.
horizontal gate signal S204 with pulse width T-C
(waveform f in the same figure). Horizontal gate signal S
204 and the first vertical gate signal S202 as two inputs, a first integral command signal S5 with a pulse width T-C is formed via the gate circuit 2008 (g in the figure), and at the same time the gate Output of circuit 2006 and gate circuit 2012
A first integral reset signal having a pulse width T-r is generated by a gate circuit 2010 which has two inputs as the horizontal synchronizing signal S3 obtained through the gate circuit 2013 (see i in the figure). Similarly, horizontal gate signal S2
04 and the second vertical gate signal S203 as two inputs, a second integral command signal S6 with a pulse width Tc is formed via the gate circuit 2009 (h in the figure), and the gate circuit 2007 A second integral reset signal having a pulse width T-r is generated by a gate circuit 2011 which receives the output of the signal S3 and the horizontal synchronizing signal S3 (j in the figure).
In addition, a one-shot circuit 2016 operating at the trailing edge of the horizontal gate signal S204 forms a command strobe signal S9 with a pulse width T-S (k in the figure).
waveform).

The video signal gate circuit 22 to which each of the signals S5 to S9 is applied generates signals with the following timings. That is, the two integrators 1 and 2 sequentially and alternately integrate only the portions of the video signal S1 on the selected horizontal scanning line based on the signals S5 to S8, and obtain the first video integrated signal S221 and the second video integrated signal S221, respectively.
A video integral signal S222 is formed. For example, in the integrator 1, the moment the first integration command signal S5 becomes low level, the first integration reset signal S7 also becomes low level for a time corresponding to the pulse width T-r, so the integrator 1 shown in FIG. The switch 2207a is turned on, and this conduction causes the output signal S221 of the integrator 1 to become zero. Next, the time (T) during which the integral command signal S5 is at low level immediately after that
-C minus T-r), the analog switch 2205 remains on and integrates the video signal S1 (waveform 1 in the figure).
5 is turned off, and is held at the same time to finally form the first video integral signal S221 (waveform shown in m in the figure). The integrator 2 also performs the same operation as described above to form a second video integrated signal S222 (waveform n in the figure).
Then, the difference between these integral signals S221 and S222 is calculated by the subtracter 3, and the absolute value of the difference is further calculated by the absolute value circuit 4 and outputted as the video difference signal S10 (see o in the figure). Waveform).

At this stage, the moment when the contrast medium begins to pass through the point corresponding to the horizontal scanning line (time P in the figure)
1) The video signal S1 is at a low level only during the passage period of the contrast agent (waveform shown in FIG. 1). At this time, when the command strobe signal S9 is at a low level, the absolute value of the first video integral signal S221 is equal to the second video integral signal S2 from the immediately preceding horizontal scan.
22, and the video difference signal S10, which is the difference between the first video integral signal S221 and the second video integral signal S222, becomes larger than the previous video difference signal S10 at this point, and this large video The difference signal S10 will be applied to the command generation circuit 23. In the command generation circuit 23, when the video difference signal S10 reaches the reference voltage Eo generated by the power supply 2302 and the resistor R2303, the comparator 6 operates, and the level conversion transistor 23
03 collector potential, that is, the comparison detection signal S231
maintains a high level (waveform on p in the figure). Therefore,
At the point in time when the signal S231 is at a high level and the command strobe signal S9 is at a low level (time P2 in the figure), the gate circuits 2305 and 2307 operate, and the X-ray imaging start command signal S11 with a pulse width T-S is activated. is formed and transferred to the X-ray controller 24 (waveform t in the figure). Flip-flop circuit 2306
is in a reset state when the power is turned on, and this output signal S233 is at a low level. Thereafter, the flip-flop circuit 2306 enters the preset state by applying the set signal S4, and the output signal S2
33 is a high level. In this state, the signal S232 is applied to the clock terminal (ck), and the signal S232 is applied to the clock terminal (ck).
Flip-flop circuit 2 at the trailing edge of 32
The output signal S233 of 306 operates to be at a low level, resulting in a reset state. Therefore, unless the set switch 21 is pressed again, the reset state is maintained, preventing unexpected X-ray exposure and ensuring the safety of the apparatus. Next, in response to the X-ray photography start command signal S11, X-rays are irradiated from the X-ray tube device 11 via the X-ray control device 24 and the high voltage generator 25, and almost in synchronization with this, the X-ray film 14 is moved from the fluoroscopy position A to the photographing position B, and a desired X-ray photograph can be taken.

According to the apparatus of the present invention described in detail above, all the drawbacks of the conventional method of simply comparing the video signal level on one horizontal scanning line on the monitor of an X-ray television apparatus with a predetermined level for each frame can be eliminated. be able to. That is, in the device of the present invention, the video signal on the horizontal scanning line is sequentially and alternately distributed for each frame, integrated and held by two integrators, and the results are compared. Because it uses a method of irradiating X-rays during fluoroscopy, it is not affected by level fluctuations in the overall video signal, and problems arise due to uncertain judgments at the video signal level of the skeleton and contrast agent. This eliminates all problems caused by movement of the patient and the movement of the subject, and the timing of X-ray photography can always be accurately compensated for, making it easy to obtain the optimal X-ray photographs for diagnosis. In addition, since the problem of taking multiple photographs that have no diagnostic value is completely eliminated, the diagnostic time for each patient can be reduced and the processing capacity can be improved, so the radiation dose per patient can be reduced. can be reduced.

The present invention is not limited to the embodiments described above, and for example, instead of the pulse control circuit 20, video signal gate circuit 22, and command generation circuit 23, a microcomputer system in which an analog-to-digital converter is added to an integrator may be used. The X-ray imaging start command signal S11 may be output by inputting the vertical synchronization signal S2, the horizontal synchronization signal S3, and the video signal S1. Furthermore, if the characteristic pattern of the video signal when a contrast agent passes through the organs of the human body is stored and X-ray photography is performed by comparing it with the pattern, even more effective X-ray photographs can be obtained. Furthermore, if the characteristic patterns are continuously stored and compared pattern by pattern as the contrast medium passes through, continuous imaging becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of a specific configuration of a pulse control circuit used therein, and FIG. 3 is a video signal gate used in FIG. 1. A circuit diagram showing an example of a specific configuration of the circuit, FIG.
A circuit diagram showing an example of a specific configuration of the command generation circuit used in the figure, and FIGS. 5 and 6 are timing charts for explaining the operation. 1, 2...Integrator, 3...Subtractor, 4...Absolute value circuit, 6...Comparator, 14...X-ray film, 17...X
Line television camera device, 18...Camera control device, 19...Monitor, 20...Pulse control circuit, 21...Set switch, 22...Video signal gate circuit, 23...Command generation circuit, 2
014...Shift register, 2016...One shot circuit, 2205-2208...Analog switch.

Claims (1)

[Scope of Claims] 1. In an X-ray diagnostic apparatus that selectively photographs any location through which a contrast medium swallowed by a subject passes as a target imaging site for diagnosis, A pulse control circuit that selects one or several consecutive horizontal scanning lines and a group of control signals generated from the pulse control circuit extract only the video signal of the portion corresponding to the horizontal scanning line, and A video signal gate circuit that sequentially and alternately integrates the signal by two integrators to form a video difference signal that is the difference between the output signals of the two; An X-ray diagnostic apparatus comprising: a command generating circuit that instructs to start X-ray imaging when the video difference signal based on a change in the video signal reaches a certain level or higher. 2. The pulse control circuit includes a shift register that forms a gate pulse signal for identifying a horizontal scanning line in relation to a vertical synchronization signal and a horizontal synchronization signal in the X-ray television apparatus, and a shift register for each of the two integrators. 2. The X-ray diagnostic apparatus according to claim 1, further comprising a gate circuit for providing an integral command signal and an integral reset signal, and a one-shot circuit for generating a command strobe signal within said command generating circuit.