JPH03210798A - X-ray diagnostic device - Google Patents

Abstract

PURPOSE:To detect an abnormality of wave tail removing action with a simple constitution by judging such a detection result that the level of a high voltage wave tail cutting current is lower than a prescribed one as an abnormality and stopping an exposure to X-rays. CONSTITUTION:When a high voltage pulse is applied to X-ray tube 42 from a high voltage generator 39, a high voltage wave tail cutting device 38 makes a charge on high voltage cables 40, 41, 43, 44, to be forcedly discharged by making a pair of high voltage proof vacuum tubes 45, 46 conduct for a fixed period at an X-ray off signal from an X-ray controller 61 each time an application of a high voltage pulse ends. Then, high voltage wave tail cutting current detection resistances 47, 48 are installed at vacuum tubes 45, 46, respectively, and when a current is not detected by the resistances 47, 48 and in case this detection level is lower than a prescribed level, it is considered that an abnormality occurs at the device 38, and the X-ray exposure is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) The present invention relates to an X-ray diagnostic apparatus equipped with a high-pressure wave tail cutting section.

(Prior Art) In an X-ray diagnostic apparatus that performs pulse fluoroscopy, a high-voltage generator supplies an X-ray tube with high-voltage pulses as shown in FIG. However, the generation of wave tails shown with diagonal lines in the high-voltage pulse waveform cannot be avoided. The generation of this wave tail is undesirable because it gives an extra dose of radiation to the subject and adds heat load to the X-ray tube. For this reason, an X-ray diagnostic apparatus is usually equipped with a high-pressure wave tail cutting section that removes the wave tail and supplies a high-voltage pulse having a waveform as shown in FIG. 3(b) to the X-ray tube.

FIG. 4 is a block diagram showing a conventional configuration example of an X-ray diagnostic apparatus equipped with such a high-pressure wave tail cutting section. In the figure, reference numeral 1 denotes a high-pressure wave tail cutting device, which is comprised of a pair of high-voltage vacuum tubes 11.12 and a pair of control circuits 13.14 for controlling these, respectively. 2 is a high-voltage generator connected to the high-voltage wave tail cutting device 1 via a high-voltage cable 3.4. 15 is X
The line controller is connected to a pair of control circuits 13 and 14 of the high-pressure wave tail cutting device 1 and the high-pressure generator 2. 5 is a high-voltage bleeder (high-voltage resistor voltage divider), which is composed of high-voltage dividing resistors 16, 17, 18, and 19 connected in series, and is connected to the high-voltage wave tail cutting device 1 via a high-voltage cable 7.8. There is. 6 is an X-ray tube connected to the high voltage bleeder 5 via a high voltage cable 9.10. Here, the high-pressure bleeder 5 may be built into the high-pressure generator 2 in some cases.

When a high-voltage pulse as shown in FIG. 3(a) is applied from the high-voltage generator 2 to the X-ray tube 6, the X-ray controller 15 turns off the X-rays at every timing t2 when the application of the high-voltage pulse ends. In response to the signal, the high-voltage wave tail cutting device 1 operates to forcibly discharge the electric charges charged in each of the high-voltage cables 3 to 4 and 7 to 10 by making the pair of high-voltage vacuum tubes 11 and 12 conductive for a certain period of time. . As a result, the waveform of the high-voltage pulse in Fig. 3(a) is corrected as shown in Fig. 3(b) by removing the wave tail, and this high-voltage pulse is
The voltage is applied to the wire tube 6. Therefore, the X-ray tube 6 does not emit unnecessary X-rays due to the wave tail.

If some abnormality occurs in the high-pressure wave tail cutting device ll and it no longer operates normally, the wave tail will not be cut and the waveform shown in FIG. 3(a) will remain in the X-ray tube 6. It will be applied. For this reason, a high-pressure bleeder 5 is provided as a protection means to detect any abnormality in the high-pressure wave tail cutting device 1 and to stop the X-ray tube 6 from emitting X-rays.

The signal on the Φ side of the high voltage pulse is the voltage dividing resistor 1 of the high voltage bleeder 5.
8, and the e-side signal is detected by a voltage dividing resistor 19 and input to error amplifiers 20 and 21, respectively. Note that since the high voltage pulse can be measured independently on the ■ side and the e side, the structure is such that an abnormality can be detected on either the ■ side or the θ side alone. The amplified high voltage pulses are output via analog switches 22, 23 to integrators 24, 25, respectively. Here, the analog switches 22 and 23 are controlled to be turned on for a certain period of time by a timer 31 triggered by an X-ray off signal 28 sent from the determined by the time constant. This on time is determined by the high voltage vacuum tube 1 as described above for the high voltage wave tail cutting device 1.
This is the time during which the wave tail cutting operation is performed by making 1.12 conductive.

If the high-voltage wave tail cutting device 11 does not operate normally for some reason during this time, the capacitors 26, 27 of the integrating amplifiers 24, 25 are charged by this wave tail. This charge voltage is applied to the integrating amplifier 2
4.25 and is compared with a level preset to a predetermined value by a variable resistor 34.35 by a comparator 32.33. If it exceeds the predetermined level, it is considered that an abnormality has occurred, and a NOR signal is output from the comparator 32.33. An abnormality signal is output to the gate 36. This sets the flip-flop 37, and an X-ray stop signal is output from the flip-flop 37 and applied to the X-ray controller 15. Subsequently, the X-ray tube 6 is controlled by the X-ray controller 15.
stops X-ray exposure.

In this way, when an abnormality occurs in the high-pressure wave tail cutting device 1, the system is configured such that this is detected and a protective operation such as stopping the X-ray tube 6 is performed. As described above, even if an abnormality occurs on either the Φ side or the e side of the high voltage pulse, it can be independently detected and protected.

(Problem to be Solved by the Invention) Conventional X-ray diagnostic equipment is equipped with a high-voltage bleeder to detect abnormalities in the wave tail removal operation of high-voltage pulse signals, which complicates the circuit configuration and increases costs. The problem is that it is unavoidable. In other words, the high voltage bleeder requires high voltage resistors, which are combined to form a voltage dividing resistor, which inevitably increases complexity.

The present invention has been made in response to the above-mentioned problems.
It is an object of the present invention to provide an X-ray diagnostic apparatus that can detect an abnormality in wave tail removal operation with a simple configuration.

[Configuration of the Invention (Means for Solving the Problem) In order to achieve the above object, the present invention comprises a high voltage generation section and an
In an X-ray diagnostic equipment equipped with a high-voltage wave tail cutter that is connected to a radiation tube via a high-voltage cable and forcibly discharges the electric charge charged in the high-voltage cable, the high-voltage wave tail cutter provided in the high-voltage wave tail cutter The present invention is characterized by comprising a detection means for detecting a wave tail cutting current and a protection means for outputting an X-ray stop signal when the detection result is below a predetermined level.

(Function) The current is detected by the high-voltage wave-tail cutting current detection means provided in the high-voltage wave-tail cutting section, and when the current is no longer detected and this detection level is below a predetermined level, the high-voltage wave It is assumed that an abnormality has occurred in the tail cutting device.
Radiation exposure is stopped. This makes it possible to detect abnormalities in the high-pressure wave tail cutting section with a simple configuration, thereby reducing costs.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a wiring diagram showing an embodiment of the X-ray diagnostic apparatus of the present invention, in which 38 is a high-pressure wave tail cutting device, and a pair of high-voltage vacuum tubes 45.
46 and a pair of control circuits 13.1 that control each of them.
Further, wave tail cutting current detection resistors 47, 48 are connected between each high voltage vacuum tube 45, 46 and the ground.

A high voltage generator 39 is connected to the high voltage wave tail cutting device 38 via high voltage cables 40 and 41.

61 is an X-ray controller connected to a pair of control circuits 13 and 14 of the high-pressure wave tail cutting device 1 and the high-pressure generator 2. 42
is an X-ray tube connected to the high-voltage wave tail cutting device 38 via high-voltage cables 43,44.

When a high-voltage pulse as shown in FIG. 2(a) is applied from the high-voltage generator 39 to the X-ray tube 42, the X-ray controller 61 turns off the X-rays at every timing t2 when the application of the high-voltage pulse ends. Based on the signal, the high-voltage wave tail cutting device 38 operates to forcibly discharge the charges stored in the high-voltage cables 40, 41, 43, and 44 by making the pair of high-voltage vacuum tubes 45 and 46 conductive for a certain period of time. do. As a result, the waveform of the high-voltage pulse in Fig. 2(a) is removed and modified as shown in Fig. 2(b), and this high-voltage pulse is
The voltage is applied to the wire tube 42. Therefore, the X-ray tube 42 does not emit unnecessary X-rays due to the wave tail.

Here, the high pressure vacuum tube 45 is cut by the high pressure wave tail cutting device 38.
．． When 46 is made conductive, it is detected by the flow of a high-voltage wave-tail cutting current as shown in FIG. This high voltage wave tail cutting current starts flowing at the moment t2 when the wave tail starts, and stops flowing at the moment t3 when the discharge of each high voltage cable 40, 41, 43, 44 ends.

The high-voltage wave tail cutting currents detected by these voltage dividing resistors 47 and 48 are input to error amplifiers 49 and 49 respectively as resistor terminal voltages.
50 is input. The amplified high voltage pulses are each input to an integrating amplifier 51,52. At this time, if the high voltage wave tail cutting device 38 is operating normally, the high voltage wave tail cutting current is detected by the voltage dividing resistor 47.48, so the integrating capacitors 53 and 54 of the integrating amplifiers 51 and 52 are charged. The output voltage of the integrating amplifiers 51 and 52 increases. This output voltage is determined by comparator 55.561. : is added and compared with a level set in advance to a predetermined value by variable resistors 57 and 58. The output voltage of the comparators 55 and 56 is H when the high voltage wave tail cutting device 38 is operating normally.
(High) level, but the integrating amplifier 5
When the output voltage of 1.52 exceeds a predetermined level, it is considered that an abnormality has occurred, and the output of comparator 55.56 is inverted from H level to L (Low) level, and an abnormal signal is output to OR gate 59. . Here OR gate 59
is connected to one input terminal of the NAND gate 60,
An inverter 66 is connected to the other input terminal of the NAND gate 60.

The NAND gate 60 is controlled to be turned on for a certain period of time by an inverted signal via an inverter 66 of a timer 63 that is triggered by a pulse fluoroscopy start signal 62 sent from an X-ray controller 61. 65. A timer 63 is a flip-flop 6 connected to the output side of the NAND gate 60 for a certain period of time from the start of pulse fluoroscopy.
7 is not set, but is provided to delay detection by the time until the output voltage of the integrating amplifiers 51 and 52 rises in normal operation.

When a wave-tail cutting current is detected in normal operation,
The flip 70 knob 67 can continue to emit X-rays while remaining reset.

However, if the high voltage wave tail cutting device 38 becomes defective for some reason and high voltage wave tail cutting is no longer performed, the high voltage wave tail cutting current will not be detected and the capacitors 53 and 54 of the integrating amplifiers 51 and 52 will be charged. The accumulated charge is discharged by the discharge resistor 68.69, and is then transferred to the integrating amplifier 51.5.
2's output decreases. When this output becomes lower than a predetermined level, the outputs of the comparators 55 and 56 are again inverted from L level to H level. This causes the inverted signal to be passed to the OR gate 59. A flip-flop 67 is controlled to be set via a NAND gate 60. Therefore, an X-ray stop signal is output from the flop flop 67 and applied to the X-ray controller 15, so that the X-ray tube 42
stops X-ray exposure.

As described above, according to this embodiment, the pair of high-voltage vacuum tubes 45 and 46 of the high-voltage wave-tail cutting device 38 are each provided with a high-voltage wave-tail cutting current detection resistor 47.48, and the current is detected by the detection resistor 47.48. If the detection level is below a predetermined level when the high-pressure wave tail cutting device 38 is no longer detected, it is assumed that an abnormality has occurred in the high-pressure wave tail cutting device 38, and the X-ray exposure can be stopped.

Therefore, by providing the detection resistors 47 and 48 in the high-voltage wave tail cutting device 38, the abnormality can be easily detected, so that a complicated circuit configuration as in the conventional case is not required, and the purpose can be achieved with a simple configuration. Therefore, it is possible to reduce costs.

Note that the high-voltage pulse is configured so that it can be measured independently on the side (■) and the side (e), so that even if an abnormality occurs on either side, it can be dealt with independently. If an abnormality occurs at the start of pulse fluoroscopy and the high-pressure wave tail is not cut off, the purpose can be achieved by setting the flip-flop 67 after a delay time determined by the timer 63.

As another embodiment of the present invention, a Hall element can be used in place of the voltage dividing resistors 47 and 48 provided in the high voltage wave tail cutting device 38. In this case, the Hall element is not directly connected to the line connecting each high-voltage vacuum tube 45, 46 to the ground like a resistor, but is placed around the line to directly discharge the charge. According to this embodiment, the object can be achieved with a simple configuration, and the same effects as in the previous embodiment can be obtained.

[Effects of the Invention] As described above, according to the present invention, the high-voltage wave-tail cutting device is provided with a means for detecting the high-voltage wave-tail cutting current, and when the detection result is below a predetermined level, it is determined to be abnormal and the X-ray Since the exposure is stopped, an abnormality in the wave tail removal operation can be detected with a simple configuration, and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a wiring diagram showing an embodiment of the X-ray diagnostic apparatus of the present invention;
FIGS. 2(a), (b), and (c) are timing charts explaining the operation of this embodiment. FIGS. 3(a) and (b) are timing charts explaining the operation of the conventional device. FIG. is a wiring diagram showing a conventional device. 38... High pressure wave tail cutting device, 39... High pressure generator, 42... X-ray tube, 45.4
6... High voltage vacuum tube, 49.50... Error amplifier, 51.52... Integrating amplifier, 53.54... Capacitor, 55.56... Comparator, 60... NAND gate, 61 ...X-ray controller, 67...flip-flop.

Claims (4)

[Claims] (1) In an X-ray diagnostic apparatus equipped with a high-voltage wave tail cutting section that is connected between a high-voltage generating section and an X-ray tube via a high-voltage cable and forcibly discharges the electric charge charged in the high-voltage cable, X-ray diagnosis characterized by comprising: a detection means provided in the high-voltage wave tail cutting section to detect a high-voltage wave tail cutting current; and a protection means that outputs an X-ray stop signal when the detection result is below a predetermined level. Device. (2) The X-ray diagnostic apparatus according to claim 1, wherein the detection means is provided between the high voltage vacuum tube and ground. (3) The X-ray diagnostic apparatus according to claim 1, wherein the detection means comprises a resistor. (4) X according to claim 1, wherein the detection means comprises a Hall element.
Line diagnostic equipment.