JP2012223368A - X-ray diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of a fringe-type noise in an X-ray image during ablation treatment.SOLUTION: This X-ray diagnostic apparatus 1 includes: an X-ray irradiator 3a irradiating X-rays to a subject P; an X-ray plane detector 3b accumulating the X-rays transmitted through the subject P as charges, reading the accumulated charges to perform detection, and affected by a magnetic field generated by current application to an ablation catheter 7a inserted into the subject P; and a controller 8 synchronizing an ablation device 7 applying a current to the ablation catheter 7a and the X-ray plane detector 3b, and adjusting charge reading timing of the X-ray plane detector 3b and current application timing of the ablation device 7.

Description

  Embodiments described herein relate generally to an X-ray diagnostic apparatus, for example, an X-ray diagnostic apparatus that captures an X-ray image of a region of interest of a subject.

  The X-ray diagnostic apparatus includes an imaging unit that images a subject (for example, a patient or a test subject) on a couch top, a C-arm that holds the imaging unit, and the like. The imaging unit is moved to a position, an X-ray image of a predetermined part of the subject is captured by the imaging unit, and the captured image is displayed on a monitor (see, for example, Patent Document 1). The imaging unit includes an X-ray irradiator that irradiates X-rays and an X-ray flat panel detector that detects the X-rays. The X-ray irradiator irradiates the subject with X-rays, and the subject. X-rays transmitted through the X-ray are detected by an X-ray flat panel detector.

  The aforementioned X-ray diagnostic apparatus is used, for example, when treating arrhythmia. As one of the treatments for this arrhythmia, ablation (pulmonary vein isolation ablation) aimed at radical treatment of atrial fibrillation by blocking conduction between the pulmonary vein myocardium and left atrial muscle by cauterization to the pulmonary vein opening Has been done. At this time, the position of the pulmonary vein opening or the like is confirmed by a doctor or the like using the X-ray image. Ablation increases the temperature at the tip of the catheter by passing a current of about 10 to 70 W at about 300 to 750 kHz between the ablation catheter inserted into the body and the counter electrode attached to the patient's body surface. This is a technique to cauterize the target part.

JP 2000-33083 A

  However, in the above-described ablation treatment, when a current is applied to the ablation catheter, a magnetic field is generated by the application of the current. Therefore, the generated magnetic field is read out from an X-ray flat detector (in particular, a charge signal read out provided in the X-ray flat detector). Circuit), striped noise occurs in the X-ray image during ablation treatment.

  The present invention has been made in view of the above, and an object thereof is to provide an X-ray diagnostic apparatus capable of suppressing the occurrence of striped noise in an X-ray image during ablation treatment.

  An X-ray diagnostic apparatus according to an embodiment of the present invention includes an X-ray irradiator that irradiates a subject with X-rays, and a detector that accumulates X-rays transmitted through the subject as charges, and reads and detects the accumulated charges An X-ray flat panel detector that is affected by a magnetic field generated by applying a current to an ablation catheter inserted into a subject, and an ablation device that applies current to the ablation catheter and the X-ray flat panel detector are synchronized. And a control device that adjusts the charge readout timing of the X-ray flat panel detector and the current application timing of the ablation device.

1 is a diagram showing a schematic configuration of an X-ray diagnostic apparatus according to a first embodiment of the present invention. It is a figure which shows schematic structure of the X-ray plane detector with which the X-ray diagnostic apparatus shown in FIG. 1 is provided. It is a block diagram for demonstrating control by the control apparatus with which the X-ray diagnostic apparatus shown in FIG. 1 is provided. It is explanatory drawing for demonstrating the various signals used for the control which the control apparatus shown in FIG. 3 performs. It is explanatory drawing for demonstrating the various signals used for the control which the control apparatus with which the X-ray diagnostic apparatus which concerns on the 2nd Embodiment of this invention is provided.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the X-ray diagnostic apparatus 1 according to the first embodiment of the present invention images a bed 2 on which a subject P such as a patient is placed and a subject P on the bed 2. The imaging unit 3, a high voltage generation device 4 that generates a high voltage to be supplied to the imaging unit 3, a moving device 5 that holds the imaging unit 3 and moves it to the imaging position, and an image such as an X-ray image are displayed. An ablation device 7 having a display unit 6, an ablation catheter 7a, and a control device 8 for controlling each unit are provided.

  The bed 2 includes a rectangular top plate 2a on which the subject P is placed, and a top drive unit 2b that supports the top plate 2a and moves it horizontally and vertically. The top plate drive unit 2b has a moving mechanism for moving the top plate 2a, a drive source (none of which is shown) for supplying driving force for the movement, and the like. The top plate driving unit 2 b is electrically connected to the control device 8, and the driving thereof is controlled by the control device 8. Such a bed 2 moves the top plate 2a to a predetermined height by the top plate driving unit 2b, and further moves the subject 2 on the top plate 2a to a predetermined position by moving the top plate 2a in the horizontal direction. Let

  The imaging unit 3 includes an X-ray irradiator 3a that irradiates the subject P on the top 2a of the bed 2 with X-rays, and an X-ray flat panel detector 3b that detects X-rays transmitted through the subject P. It has. The imaging unit 3 is provided so as to be movable around the couchtop 2a of the bed 2. The imaging unit 3 moves to an imaging position and images an X-ray image of a target region of the subject P on the couchtop 2a from the imaging position. To do. As this X-ray image, for example, a fluoroscopic image of a blood vessel or the like is captured.

  The X-ray irradiator 3a includes an X-ray tube that emits X-rays and an X-ray restrictor (none of which is shown) that narrows the X-rays emitted from the X-ray tube. For example, a collimator is used as the X-ray diaphragm. The X-ray irradiator 3 a is electrically connected to the control device 8 via the high voltage generator 4, and the driving thereof is controlled by the control device 8. Such an X-ray irradiator 3 a emits X-rays with an X-ray tube, squeezes the X-rays with an X-ray restrictor, and irradiates the subject P on the top 2 a of the bed 2.

  The X-ray flat panel detector 3b is provided in the moving device 5 so as to face the X-ray irradiator 3a, and is formed so as to be movable toward and away from the facing X-ray irradiator 3a. This X-ray flat panel detector 3b is electrically connected to the control device 8, accumulates X-rays transmitted through the subject P on the top 2a as charges, reads the accumulated charges, and controls the charge signal. It transmits to the device 8 (details will be described later). As the X-ray flat panel detector 3b, a flat panel detector (FPD) such as a direct conversion method or an indirect conversion method is used.

  The high voltage generator 4 is a device that generates a high voltage to be supplied to the X-ray irradiator 3a, boosts and rectifies the voltage supplied from the control device 8, and supplies the voltage to the X-ray irradiator 3a. The control device 8 controls the voltage waveform, that is, the amplitude, the pulse width, and the like.

  The moving device 5 includes a holding arm 5a that holds the X-ray irradiator 3a and the X-ray flat panel detector 3b facing each other, an arm support portion 5b that supports the holding arm 5a so as to be slidable, and an arm support portion 5b. And a support column 5c that rotatably supports the support 5c. The moving device 5 is electrically connected to the control device 8, and its movement is controlled by the control device 8.

  The holding arm 5a is, for example, a C-shaped C-arm, and is provided on the arm support portion 5b so as to be slidable in the extending direction of the arm. An X-ray irradiator 3a is provided at one end of the holding arm 5a in the longitudinal direction, and an X-ray flat panel detector 3b is provided at the other end. The arm support 5b is rotatably provided on the column 5c, and the column 5c is erected on the floor surface.

  The display unit 6 is a display device that displays various images such as an X-ray image. In FIG. 1, two display units 6 are provided as an example. The display unit 6 is electrically connected to the control device 8 and displays various images such as an X-ray image sent from the control device 8. For example, a liquid crystal display or a CRT (Cathode Ray Tube) display is used as the display unit 6.

  The ablation device 7 includes an ablation catheter 7a inserted into the body of the subject P on the top 2a, and supplies an electric current, for example, a high frequency current, to the ablation catheter 7a. A counter electrode plate 7b corresponding to the ablation catheter 7a is attached to the body surface of the subject P such as a patient. The ablation device 7 is electrically connected to the control device 8, and the driving thereof is controlled by the control device 8.

  Here, in the ablation treatment, the ablation catheter 7a is inserted into the body of the subject P on the top plate 2a, and in this state, between the ablation catheter 7a and the counter electrode plate 7b attached to the body surface of the subject P. A current of about 10 to 70 W is passed at about 300 to 750 kHz. Thereby, the catheter tip temperature becomes high and the target site is cauterized.

  The control device 8 includes a drive control unit 8a that controls driving of the bed 2 and the moving device 5, an X-ray image collection device 8b that collects X-ray images, and a detector control unit 8c that controls the X-ray flat panel detector 3b. And.

  The drive control unit 8a has a control unit that controls driving of each unit, a storage unit that stores various programs and data, and an input unit that receives input operations from operators such as an operator and an assistant (none of which are shown). is doing. The drive control unit 8a controls the movement of the bed 2 and the moving device 5 in accordance with an input operation of the operator with respect to the input unit. The operator performs an input operation on the input unit, and moves the top plate 2a of the bed 2 and the X-ray irradiator 3a and the X-ray flat panel detector 3b constituting the imaging unit 3 to desired imaging positions. In addition, as an input part, input devices, such as various buttons and a joystick, are used, for example.

  The X-ray image acquisition apparatus 8b has a control unit such as a microprocessor, a storage unit that stores various programs and data, and an input unit that receives input operations from operators such as an operator and an assistant (none of which are shown). is doing. The X-ray image acquisition apparatus 8b irradiates the subject P on the top 2a with X-rays by the X-ray irradiator 3a, and then X-rays based on the X-ray image signal from the X-ray flat panel detector 3b. A line image is generated, the generated X-ray image is stored in a storage unit or the like, and further displayed on the display unit 6. The operator performs an input operation on the input unit, inputs information relating to imaging of an X-ray image, and selects an imaging mode or the like. For example, an input device such as a keyboard or a mouse is used as the input unit.

  The detector control unit 8c notifies the X-ray flat panel detector 3b of the readout timing for reading the accumulated charges. The detector control unit 8c is electrically connected to the X-ray image acquisition device 8b, and transmits the charge signal read by the X-ray flat panel detector 3b to the X-ray image acquisition device 8b as an X-ray image signal.

  Next, the X-ray flat panel detector 3b will be described in detail with reference to FIG.

  As shown in FIG. 2, the X-ray flat detector 3b is provided with a charge signal readout circuit 3b1. The charge signal readout circuit 3b1 includes a power supply device 11, a plurality of pixels 12 arranged in an array in the row direction (for example, the horizontal direction in FIG. 2) and the column direction (for example, the vertical direction in FIG. 2), A gate driver 13 for supplying a control signal to the pixel 12, a plurality of amplifiers 14 for amplifying the charge signal, a multiplexer 15 for converting a parallel signal from the amplifiers 14 into a serial signal, and an analog signal as a digital signal. An A / D conversion unit 16 for conversion is provided.

  Each pixel 12 includes an X-ray detection unit 12a that converts X-rays into charges, a semiconductor switch 12b such as a TFT (thin film transistor), and a charge storage unit 12c such as a capacitor that stores charges. The drain electrode of the semiconductor switch 12b is electrically connected to the X-ray detection unit 12a and the charge storage unit 12c. The gate electrode of the semiconductor switch 12 b is electrically connected to the scanning line 17. The source electrode of the semiconductor switch 12 b is electrically connected to the signal line 18. The semiconductor switch 12b functions as a read switch that reads the charges accumulated by the charge accumulation unit 12c to the amplification unit 14.

  The gate driver 13 controls the on / off of the semiconductor switch 12b in units of rows by supplying a control signal to each scanning line 17 respectively. The gate driver 13 functions as a drive circuit that operates each semiconductor switch 12b in units of rows.

  The amplifying unit 14 is constituted by, for example, an operational amplifier 14a, and the signal line 18 is connected to one input terminal thereof, and the other input terminal is grounded. A capacitor 14b is connected between the input terminal connected to the signal line 18 and the output terminal, and the amplifying unit 14 has an integration function. Further, a switch 14c is connected in parallel to the capacitor 14b, and the amplifying unit 14 closes the switch 14c to discharge the electric charge remaining in the capacitor 14b.

  The multiplexer 15 sequentially selects the charge signal input from each amplifier 14, converts the parallel output from each amplifier 14 into a serial output, and sends it to the A / D converter 16 at the subsequent stage.

  The A / D converter 16 converts the analog signal input from the multiplexer 15 into a digital signal, and transmits it as an X-ray image signal to the X-ray image acquisition device 8b via the detector control unit 8c.

  In such an X-ray flat panel detector 3b, when a high-frequency current is applied to the ablation catheter 7a, the magnetic field generated by the ablation catheter 7a affects the charge signal readout circuit 3b1, particularly the power supply device 11. Due to this magnetic field, noise is generated in the voltage applied to the pixel 12 via the gate driver 13, and the charge signal that is changed and read by the noise is amplified by the amplification unit 14, and is supplied to the A / V via the multiplexer 15. The signal is input to the D converter 16, converted to a digital signal by the A / D converter 16, and output to the subsequent stage. The noise is striped noise because the amplitude is different for each pixel arranged in each row that is switched on and off in time series by the gate driver 13.

  As described above, the X-ray flat panel detector 3b accumulates X-rays irradiated by the X-ray irradiator 3a and transmitted through the subject P on the top 2a as charges, and detects the accumulated charges by reading them. The detector is affected by the magnetic field generated by the ablation catheter 7a inserted into the subject P.

  Therefore, during the charge signal readout period, control is performed to stop the application of the high-frequency current to the ablation catheter 7a. This makes it possible to output a non-fluctuating charge signal to the subsequent stage. Therefore, the ablation device 7 that supplies current to the ablation catheter 7a and the X-ray flat panel detector 3b are synchronized, and the charge reading timing for reading out the charges accumulated by the X-ray flat panel detector 3b and the ablation device 7 to the ablation catheter 7a. It is necessary to adjust the current application timing for applying the current.

  This timing adjustment will be described in detail with reference to FIGS.

  As shown in FIG. 3, the X-ray flat panel detector 3b is provided with the aforementioned charge signal readout circuit 3b1 for reading out a charge signal, and the high voltage generator 4 has a pulse applied to the X-ray irradiator 3a. A pulse X-ray generation unit 4a that generates X-rays is provided. Further, the ablation device 7 is provided with a current application controller 7a1 for controlling the application timing of current. Further, the X-ray image acquisition device 8b is provided with a selection unit 8b1, a master clock generation unit 8b2, a pulse X-ray clock generation unit 8b3, a delay time set value memory 8b4, and an ablation pulse generation unit 8b5. The detector control unit 8c is provided with a read clock generator 8c1.

  The selection unit 8b1 selects an imaging mode according to an operator's input operation on the input unit. The master clock generator 8b2 generates a main master clock based on the imaging mode selected by the selector 8b1. The pulse X-ray clock generation unit 8b3 generates, for example, a pulse X-ray clock signal as shown in FIG. 4 based on the generated master clock, and transmits the pulse X-ray clock signal to the pulse X-ray generation unit 4a of the high voltage generator 4. The pulse X-ray generation unit 4a generates, for example, a pulse X-ray signal as shown in FIG. 4 based on the received pulse X-ray clock signal, and transmits the pulse X-ray signal to the X-ray irradiator 3a. The X-ray irradiator 3a irradiates the subject P on the top 2a with X-rays based on the received pulse X-ray signal.

  In addition, the selection unit 8b1 sets the delay time b corresponding to the selected imaging mode in the delay time setting value memory 8b4 according to the above selection. The read clock generation unit 8c1 generates, for example, a read clock signal as shown in FIG. 4 based on the delay time b and the master clock set in the delay time set value memory 8b4, and the charge signal of the X-ray flat panel detector 3b. The data is transmitted to the readout circuit 3b1. As shown in FIG. 4, the read clock signal is generated so as to rise after a delay time b after the pulse X-ray clock signal rises. The charge signal read circuit 3b1 controls each semiconductor switch 12b via the gate driver 13 based on the received read clock signal, and reads the charge signal.

  The delay time b and the master clock are transmitted to the ablation pulse generator 8b5, and the ablation pulse generator 8b5 generates an ablation pulse signal as shown in FIG. 4 based on the received delay time b and the master clock, for example. It transmits to the current application controller 7a1 of the ablation device 7. As shown in FIG. 4, the ablation pulse signal is in the on state (current application state) during the charge accumulation period and is in the off state (current application stop state) during the charge readout period, as shown in FIG. Is generated. The current application controller 7a1 controls application of current to the ablation catheter 7a based on the received ablation pulse signal.

  In this way, during the accumulation period in which the X-ray flat panel detector 3b accumulates X-rays as electric charges, current is applied to the ablation catheter 7a, and during the readout period in which the electric charges accumulated by the X-ray flat panel detector 3b are read out. The current application to the ablation catheter 7a is stopped. As a result, the generation of the magnetic field due to the current application to the ablation catheter 7a is limited to the non-reading period, which is the accumulation period, and therefore no magnetic field is generated during the reading period. For this reason, it is possible to avoid the influence of the magnetic field on the charge signal readout circuit 3b1 during the readout period, so that it is possible to reliably prevent the occurrence of striped noise in the X-ray image.

  As described above, according to the first embodiment of the present invention, the ablation device 7 that applies current to the ablation catheter 7a and the X-ray flat detector 3b are synchronized, and the X-ray flat detector 3b The charge readout timing and the current application timing of the ablation device 7 are adjusted. As a result, it is possible to prevent the charge signal readout circuit 3b1 of the X-ray flat panel detector 3b from being affected by the magnetic field generated by the application of current to the ablation catheter 7a, so that the X-ray image during ablation treatment is striped. Generation of noise can be suppressed. As a result, a good X-ray image can be provided, and the inspection time can be shortened and the exposure can be reduced.

  In particular, during the accumulation period in which the X-ray flat panel detector 3b accumulates X-rays as electric charges, current is applied to the ablation catheter 7a, and during the readout period in which the electric charges accumulated by the X-ray flat panel detector 3b are read out, Current application to the ablation catheter 7a is stopped. As a result, since no magnetic field is generated by applying current to the ablation catheter 7a during the readout period, it is possible to avoid the influence of the magnetic field on the charge signal readout circuit 3b1, so that stripe noise appears in the X-ray image. It is possible to reliably prevent the occurrence.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIG.

  The second embodiment of the present invention is basically the same as the first embodiment. In the second embodiment, differences from the first embodiment will be described, the same parts as those described in the first embodiment will be denoted by the same reference numerals, and the description thereof will also be omitted.

  As shown in FIG. 5, in the second embodiment of the present invention, current is applied to the ablation catheter 7a during the readout period immediately after the accumulation period when the X-ray irradiator 3a does not irradiate X-rays. That is, as shown in FIG. 5, the ablation pulse signal is in the on state (current application state) during the charge accumulation period and in the charge readout period, in synchronization with the read clock signal, as in the first embodiment. Although it is generated so as to be in an off state (current application stop state), it is generated so as to be in an on state even in a reading period immediately after the accumulation period when the X-ray irradiator 3a does not irradiate X-rays. .

  Specifically, it is determined whether or not the pulse X-ray clock signal has risen, and when it is determined that the pulse X-ray clock signal has risen, the ablation pulse signal is turned off in the readout period immediately thereafter, If it is determined that the pulse X-ray clock signal has not risen, the ablation pulse signal is turned on in the readout period immediately after that.

  As described above, according to the second embodiment of the present invention, the same effect as that of the first embodiment can be obtained. Furthermore, during the readout period immediately after the accumulation period when the X-ray irradiator 3a does not irradiate X-rays, current is applied to the ablation catheter 7a. As a result, compared to the first embodiment, it is possible to lengthen the on-state period of the ablation pulse signal, and accordingly, it is possible to shorten the treatment time required for the ablation treatment.

(Other embodiments)
In addition, the above-mentioned embodiment which concerns on this invention is an illustration, and the scope of the invention is not limited to them. The above-described embodiment can be variously modified. For example, some components may be deleted from all the components shown in the above-described embodiment, and further, components according to different embodiments may be appropriately combined. Also good.

  For example, in the above-described embodiment, the master clock generator 8b2 is provided in the X-ray image acquisition device 8b. However, the present invention is not limited to this, and the ablation device 7, the X-ray flat panel detector 3b, and the detector control unit 8c. It may be provided in other devices, and any of them may be a master.

  In the above-described embodiment, the case where the ablation device 7 is used is described as an example. However, the present invention is not limited to this, and a three-dimensional mapping device that has recently been used in arrhythmia treatment is used. In this case, the contents of the above-described embodiment can be applied. The three-dimensional mapping device generates a dynamic magnetic field in the process of generating a three-dimensional mapping image. Accordingly, by limiting the generation of the dynamic magnetic field to the non-reading period of the X-ray flat panel detector 3b as in the above-described embodiment, it is possible to suppress the generation of nozzles in the X-ray image.

DESCRIPTION OF SYMBOLS 1 X-ray diagnostic apparatus 3a X-ray irradiator 3b X-ray plane detector 7 Ablation apparatus 7a Ablation catheter 8 Control apparatus P Subject

Claims (3)

An X-ray irradiator that irradiates the subject with X-rays;
A detector that accumulates the X-rays that have passed through the subject as electric charges, reads out and detects the accumulated electric charges, and is affected by a magnetic field generated by current application to an ablation catheter inserted into the subject. A line plane detector;
A control device that synchronizes the ablation device that applies current to the ablation catheter and the X-ray flat panel detector, and adjusts the charge readout timing of the X-ray flat panel detector and the current application timing of the ablation device;
An X-ray diagnostic apparatus comprising:   The control device applies current to the ablation catheter by the ablation device during the accumulation period in which the X-ray flat detector accumulates the X-rays as electric charges, and reads out the electric charges accumulated by the X-ray flat detector. The X-ray diagnostic apparatus according to claim 1, wherein during the readout period, current application to the ablation catheter by the ablation apparatus is stopped.   The control device performs current application to the ablation catheter by the ablation device during the reading period immediately after the accumulation period when the X-ray irradiator does not irradiate the X-ray. Item 3. The X-ray diagnostic apparatus according to Item 2.

Images