JPH0278198A - X-ray device - Google Patents

Abstract

PURPOSE:To prevent the abnormal rising of the degree of film blackening by setting the value obtained by correctly computing, with the timer correction rate data set by a data setting unit, the first real photographing time controlled by the automatic exposure control, as the photographing time on and after the second time. CONSTITUTION:A clock means 16 clocks the time from the start of the output of the timer signal t at the first photographing time till that an automatic exposure control circuit 9 acts. A data setting unit 18 sets the increase rate of the photographing time appropriate for compensating the degree of film blackening caused by the fullness of a contrast medium. A computing process means 11 compensately computes with said clocked value and the preset data, and when the photographing on and after the second time is the timer control photographing, the computed value is used as the timer setting value or is used as a backup timer setting value of an automatic exposure photographing circuit on and after the second time. And if the contrast medium is fulled in the capillary, the abnormal rising of the degree of film blackening is prevented so that an X-ray photograph worth diagnosing can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an X-ray apparatus having an automatic exposure control circuit,
In particular, the present invention relates to an X-ray device suitable for an X-ray device for circulatory organ examination that continuously takes images by injecting a contrast medium into a blood vessel.

[Prior Art] Conventionally, this type of apparatus has been constructed as shown in FIG. 2. A contrast examination of a blood vessel using such a conventional apparatus will be described with reference to FIG. 2.

In FIG. 2, ``■'' is an AC power supply, and 2 is an autotransformer for setting the X-ray tube voltage, which is controlled according to the set tube voltage by a known method. 3 is an X-ray irradiation switch circuit, 4 is a DC high voltage generator consisting of a high voltage converter and a rectifier, and 5 is an X-ray irradiation switch circuit.
ray tube, 6 is a subject. 7 is X for automatic exposure control
The ray detector generates an electrical signal of a magnitude corresponding to the amount of X-rays transmitted through the subject 6. A film changer 8 generates a timer drive signal S1 to start X-ray irradiation, and also sends an injection start signal S2 to the injector 10. Reference numeral 101 denotes an injection barrel through which the contrast medium is injected into the subject 6. Is 9 an automatic exposure agent? A circuit 111 integrates the electrical signal from the X-ray detector 7, and when the integrated value reaches a predetermined value, it sends a timer stop signal S3 to a timer circuit to be described later to stop outputting the timer signal t. Reference numeral 11 denotes an arithmetic processing means such as a microprocessor, which controls each part of the apparatus. 12 is a shooting start switch, I3 is a timer circuit that controls the shooting time, 14 is a RAM in which data such as timer setting values set on an operation panel (not shown) is appropriately written and read out, and 15 is a series of shooting sequences. This is a ROM in which the following information is written.

Next, the operation of the above-mentioned conventional device will be explained. First, when desired photographing conditions are set using an operation panel (not shown), the brush of the autotransformer 2 is slid to a predetermined position by a command from the arithmetic processing means 11, and the timer settings set using the operation panel are set. The value is stored in RAM 14. Next, when the photographing start switch 12 is operated, the timer setting value stored in the RAM 14 is set in the timer circuit 13. This timer circuit 13 operates as a backup timer circuit for the automatic exposure control circuit 9. When all the conditions for shooting are ready, the timer drive signal S1 is sent from the film changer 8 to the timer circuit 13.
The X-ray irradiation switch circuit 3 is operated by the output signal (timer signal) t of No. 3, and X-rays are irradiated. At the same time, the injector 10 also starts operating, and the contrast medium is injected into the subject 6. An electrical signal from the X-ray detector 7 that receives the X-rays transmitted through the subject 6 is sent to an automatic exposure control circuit 9. The automatic exposure control circuit 9 integrates the electrical signal from the X-ray detector 7,
A timer stop signal S3 that stops X-ray irradiation when the integral value reaches a predetermined value depending on the degree of film blackening.
is sent to the timer circuit 13, the output of the timer signal t is stopped, and one photographing operation is completed.

The timer drive signal S1 from the film changer 8 is generated multiple times at predetermined timing, and in synchronization with this, the timer circuit 13, the X-ray irradiation switch circuit 3, the automatic exposure control circuit 9, etc. are also activated by the same operation as described above. The device operates, irradiates X-rays multiple times, and as a result, multiple blood vessel images are taken as a continuous image.

Note that the output signal (timer signal) t of the timer circuit 13 is
In addition to driving the line irradiation switch circuit 3, the calculation processing means 1
1, so that the arithmetic processing means 11 can grasp the status of X-ray irradiation.

[Problem to be solved by the invention]

However, such conventional devices have the following problems. That is, in the conventional apparatus, in the above-mentioned series of imaging sequences, the injected contrast agent sufficiently spreads over the imaging area, and when it reaches the capillaries, the absorption of X-rays increases. The shooting time will also increase. For this reason, the degree of blackening of the film in areas other than blood vessels increases more than necessary, and areas where a density difference should be made because there is a lesion are hidden, which may impair the diagnostic value. Further, depending on the shape and position of the X-ray detector 7 with respect to the subject 6, most of the surface of the X-ray detector 7 facing the subject 6 will be covered with the contrast medium. For this reason, the overall film density may become too high, or the maximum allowable shooting time limited by the film changer 8 may be exceeded, causing the film 81 to begin to move during shooting, causing blurring due to movement. , there was also a risk that the diagnostic value would be impaired.

SUMMARY OF THE INVENTION An object of the present invention is to provide an X-ray apparatus that prevents an unnecessarily long imaging time and that can always perform X-ray photography with high diagnostic value.

[Means for solving the problem] The above purpose is to adjust the output time value of the timer signal measured by the timer (actual shooting time at the time of initial shooting by automatic exposure control) to the timer correction set by the data setting device. This is achieved by performing a correction calculation using the ratio data and operating the timer circuit using the calculation result value as the timer setting value (photographing time) for the next and subsequent shootings or the backup timer setting value of the automatic exposure control circuit.

[Effect]

The timer starts timing when the output of the timer signal is started during the first shooting, that is, at the same time as shooting starts, and finishes timing when the automatic exposure control circuit operates. The data setting device determines, for example, if the rate of increase in imaging time is 40%, which is appropriate to compensate for the decrease in the degree of film darkening due to the filling of the contrast medium.
Data of 40 is set. The arithmetic processing means performs a correction calculation using the time value of the timer, that is, the first shooting time, and the timer correction ratio data set in the data setting device, and uses the calculation result value to perform the second and subsequent shootings. As a timer setting value when is timer controlled shooting,
Alternatively, by using it as a backup timer setting value of the automatic exposure photographing circuit for the second and subsequent photographing, it is possible to obtain an X-ray photograph with diagnostic value in which the degree of film darkening does not increase abnormally.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an X-ray apparatus according to the present invention. In FIG. 1, the same reference numerals as in FIG. 2 indicate the same or corresponding parts. In addition, in FIG. 1, reference numeral 16 is a timer for measuring the output time of a timer signal, that is, a timer for measuring the time during which the timer signal is generated and the X-ray is irradiated (imaging time); here, 17 is an elapsed timer; A switch circuit 18 is a switch circuit for blocking the X-ray irradiation stop signal S3 generated from the automatic exposure control circuit 9 and preventing the automatic exposure control circuit 9 from terminating the photographing process. This is a data setting device for setting timer correction ratio data for correcting the shooting time.

In this case, the elapsed timer 16 is set and starts counting at the rising edge of the timer signal t, and ends at the falling edge of the timer signal t. In addition, the data setter 18 is, for example, 8
It uses bit digital switches.

Note that the arithmetic processing means 11 not only controls each part of the apparatus similarly to the conventional apparatus described above, but also controls the data setting device 18 in the present invention.
The timer correction ratio data set in is used to correct the time value of the elapsed timer 16, and the calculated result value is used as the timer setting value for subsequent shooting or as the backup timer setting value of the automatic exposure control circuit 9 in the timer circuit. Operate 13.

Next, the operation of the above-mentioned device of the present invention will be explained. First, before taking a series of shots, the operator uses timer correction ratio data COMP to calculate the maximum shooting time for the second and subsequent shots based on the auto exposure shooting time measured during the first shot, in light of conditions such as the area to be shot. (% value) is set in the data setter 18. The set timer correction ratio data can be read by the arithmetic processing means 11 at any timing.

After the timer correction ratio data has been set, when the shooting start switch 12 is operated for the first shooting, the timer setting value as the backup timer setting value of the automatic exposure control circuit 9 is transferred to the timer circuit 13 as in the conventional device. Set. Further, the switch circuit 17 is configured to be able to send the X-ray irradiation stop signal S3 from the automatic exposure control circuit 9 to the timer circuit 13.
is considered to be closed.

When all conditions for shooting are completed,
Shooting timer drive signal S from film changer 8
A timer signal 1 is sent to the timer circuit 13, and the X-ray irradiation switch circuit 3 is turned on to start X-ray irradiation. At the same time, the elapsed timer 16 starts operating and starts counting the time during which the X-rays are irradiated. Also, at a predetermined timing, the injector 10. The injector 101 also operates, and the contrast medium is injected into the subject 6. The timing of this injection is usually such that the contrast medium does not reach the imaging site during the first imaging.

The X-rays that have passed through the subject 6 are converted into electrical signals by the X-ray detector 7, integrated by the automatic exposure control circuit 9, and compared with a predetermined value. The automatic exposure control circuit 9 issues an X-ray irradiation stop signal S3 when the integral value of the electric signal reaches a predetermined value.
is generated and the X-ray beam is stopped. During this time, the elapsed timer 16 measures the time when the XIM was actually irradiated (actual irradiation time -
actual shooting time). Further, the arithmetic processing means 11 monitors the timer signal t, and when it is confirmed that the first photographing has been completed due to the disappearance of the timer signal t, the elapsed timer 16
Read the actual irradiation time Ts from the data setter 18.
Read the timer correction ratio data COMP from , and perform the calculation. Then, the calculation result value T is set in the timer circuit 13 as the next timer setting value, and the switch circuit 17 is opened.

As a result of the above, a series of subsequent shootings can be performed with a fixed shooting time based on the above-mentioned timer setting value (calculation result value T,) without relying on automatic exposure control. As a result, even if the film is filled with contrast medium, the degree of blackening of the film does not increase more than necessary, and X-ray photographs that extract minute changes in the contrast medium can be obtained, and continuous contrast photographs that do not overlook lesions can be obtained. In addition, if the photographing time (calculated result value T1) of the calculation result exceeds the allowable maximum photographing time T2, which is limited according to the photographing speed of the film changer 8, the photographing time from the next time onwards will be limited to the permissible maximum photographing time by the film changer 8. It may be replaced with the maximum shooting time T2, which allows the film 8 to be
It is possible to prevent the trouble that 1 starts to move.

In the above explanation, the shooting time from the next time onwards is explained as a fixed shooting time method in which the calculation result value T is taken as the shooting time. It is also possible to set the switch circuit 17 in the circuit 13 and keep the switch circuit 17 closed for subsequent shootings, so that the automatic exposure control circuit 9 is operated for all shootings. Which method is selected is determined by the operator's purpose for photographing, and selection of these methods can be easily made by adding, for example, a mode selection switch (not shown).

If the automatic exposure control circuit 9 is always operated, the switch circuit 17 in FIG. 1 can be omitted.

Furthermore, in the above explanation, the reference timer setting value T, (T in the above formula (1)) is the shooting time measured by the elapsed timer 16 for the first shooting, but for the second, third, etc. The actual photographing time may be set as a reference timer setting value T, the actual photographing time after that is determined by the above equation (1), and the t closest shadow may be determined based on the value T. This method can be easily performed using known techniques and methods by having the arithmetic processing means 11 count the number of times of photographing.

[Effects of the Invention] According to the present invention, in an X-ray apparatus that combines automatic exposure control with control of imaging time such as continuous contrast imaging, it is possible to prevent the degree of film darkening from excessively increasing abnormally due to the filling of contrast medium. This has the effect that it is possible to always obtain an X-ray photograph with an appropriate degree of darkening that has high diagnostic value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the device of the present invention, and FIG.
The figure is a block diagram of a conventional device. 1... AC power supply, 2... Auto-transformer, 3... X-ray irradiation switch circuit, 4... DC high voltage generator, 5...
・X-ray tube, 6... Subject, 7... X-ray detector, 8.
...Film changer, 9...Automatic exposure control circuit,
1o... Injector, 11... Arithmetic processing means, 1
2... Shooting start switch, 13... Timer circuit, 14... RAM, 15... ROM, 16... Elapsed timer, 17... Switch circuit, 18... Data setting device.

Claims (1)

[Claims] 1. A timer circuit that controls the shooting time, and an X that is switched by the timer signal output from this timer circuit.
A radiation irradiation switch circuit, a DC high voltage generator that boosts and rectifies the voltage switched by this switch circuit, and an X-ray tube that generates X-rays by applying the DC high voltage from this DC high voltage generator. , an X-ray detector that detects the amount of X-rays from the X-ray tube that has passed through the subject and converts it into an electrical signal; and an X-ray detector that integrates the electrical signal from this X-ray detector, and the integrated value becomes a predetermined value. An X-ray apparatus comprising an automatic exposure control circuit that stops outputting a timer signal from the timer circuit at a certain point in time, and an arithmetic processing means that controls each part of the apparatus,
The arithmetic processing means includes a timer for measuring the output time of the timer signal and a data setter for setting timer correction ratio data, and the arithmetic processing means performs a correction operation on the time value of the timer using the timer correction ratio data. The X-ray apparatus is characterized in that the calculated result value is used as a timer setting value for subsequent imaging or as a backup timer setting value of the automatic exposure control circuit to operate the timer circuit.