JPH071720B2 - X-ray equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an X-ray apparatus, and more particularly to protection of an X-ray tube, which appropriately manages the amount of heat that can be applied to the X-ray tube anode. The present invention relates to a technique for preventing an X-ray tube load, which leads to abnormal heat generation of the anode, from being applied.

[Prior art]

A conventional X-ray tube equipped with means for controlling the allowable load of the X-ray tube by monitoring the remaining amount of accumulated heat of the anode of the X-ray tube.
The wire device focused only on the maximum allowable anode accumulated heat amount, and the idea was that a single-shot load may be applied up to the allowable value as long as the remaining anode accumulated heat amount does not exceed the allowable value.

[Problems to be solved by the invention]

However, as in the recent gastrointestinal diagnosis and cardiovascular diagnosis, the amount of load applied to the anode of the X-ray tube increases with each fluoroscopy / imaging, and the load interval is narrowed. The entire anode is always heated (the amount of remaining heat is large), and the single load that can be applied next time is
Since the permissible temperature of the focal plane (portion where electrons collide) is determined by the anode material and the like, it must be lowered naturally. Based on this idea, a method has been proposed in which the surface temperature of the anode is monitored, the remaining amount of accumulated heat of the anode is constantly monitored, and the allowable value of the single load is continuously reduced and controlled according to the value. However, there is a problem that the control means becomes complicated and the cost becomes very high.

Further, in the case of monitoring the surface temperature of the anode, there is a problem that it can be applied only to a special X-ray tube device equipped with an anode surface temperature detector.

The present invention has been made to solve the above problems.

An object of the present invention is to provide a technique capable of extending the life of an X-ray tube by monitoring the amount of heat accumulated in the anode with a simple structure.

Another object of the present invention is to provide a technique capable of continuously performing imaging necessary for a series of diagnoses corresponding to the constitution of a subject within a range of an allowable value of an X-ray tube.

Another object of the present invention is to interrupt the diagnosis due to a sudden operation of the temperature limiter, which is caused by a lack of operational consideration such as providing some pause in the diagnostic time between the subject and the next subject, and sudden It is to provide a technique capable of avoiding discontinuation of diagnosis due to tube damage.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

The following is a brief description of the outline of the typical inventions among the inventions disclosed in the present application.

The present invention, for example, in the use of an X-ray device with a narrow load application interval and a large amount of residual heat of the anode, such as a digestive system diagnosis, provides the X-ray irradiation dose required for fluoroscopy / imaging per subject. This was done based on the idea that it is necessary to monitor the corresponding calorific value average value.

That is, it is possible to prevent the overload from being applied to the X-ray tube by calculating the remaining amount of heat accumulated in the anode of the X-ray tube from the X-ray tube voltage, X-ray tube current, X-ray load time and X-ray radiation stop time. In the X-ray apparatus configured as described above, a calculation means for calculating an average value of the total heat quantity of X-ray tube heat generation corresponding to the X-ray irradiation amount required to inspect one subject, and the calculation result A of the calculation means. And a comparison means for comparing the average value B of the allowable X-ray generated heat amount of the X-ray tube, and a first signal or a plurality of steps when the calculation result A reaches a predetermined value C lower than the average value B. Predetermined value Cn
When the calculation result A exceeds the average value B, a predetermined signal is generated, and a second signal is generated when the calculation result A exceeds the average value B.

Further, in each of the means, further, the first signal or the respective predetermined signal corresponding to each step is released when the X-ray emission is not restarted for a predetermined time T ₁ , and the second signal is released. The signal is an X-ray apparatus characterized in that it comprises means for releasing if the X-ray emission has not been restarted for a predetermined time T _{2 which} is longer than the predetermined time T ₁ .

[Action]

According to the above means, the amount of heat supplied to the anode per subject is calculated, the total amount of heat is averaged over the diagnostic time required for each subject, and the calculation result is regarded as the allowable value. Compare
By monitoring the amount of heat accumulated in the anode based on the result of this comparison, the amount of heat that exceeds a predetermined limit is controlled so as not to be applied to the anode, so that the life of the X-ray tube can be extended.

Further, it is possible to continuously perform imaging necessary for a series of diagnoses corresponding to the constitution of the subject within the range of the allowable value of the X-ray tube.

Example of Invention

An embodiment of the present invention will be specifically described below with reference to the drawings.

In all the drawings for explaining the embodiments, parts having the same function are designated by the same reference numerals, and repeated description thereof will be omitted.

FIG. 1 is a block diagram showing a schematic configuration of an X-ray apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a tube current / X-ray emission time detection circuit shown in FIG. FIG. 3 is a block diagram showing the configuration of the tube voltage detection circuit shown in FIG. 1, and FIG. 4 is a diagram showing tube voltage characteristics.

In FIG. 1, reference numeral 1 is an autotransformer that determines an X-ray tube voltage, and a brush 2 sets a predetermined tube voltage. 3 is an X-ray switch for turning on and off X-ray tube radiation, 4 is a main transformer for boosting, 5 is a high voltage side neutral point terminal for measuring the tube current and X-ray load time, 6 Is a high-voltage rectifier, 7 is X
It is a line tube. Reference numeral 8 is an exciting coil of the X-ray switch, and 9 is a contact operated by an X-ray ON-OFF signal from an X-ray emission control circuit such as a photographing timer.

As the X-ray switch, for example, an SCR or a Tetrode tube is used, but an electromagnetic X-ray switch is used for ease of explanation.

Reference numeral 10 denotes a tube current / X-ray emission time detection circuit, which has a circuit configuration as shown in FIG.

In FIG. 2, the tube current flowing into the high voltage side neutral point terminal 5 is rectified by the rectifier 20 and converted into a voltage by the detection resistor 21. The voltage waveform has a waveform as shown by reference numeral 23. Since the X-ray tube circuit can be regarded as a current source, the tube current value does not change even if some detection resistor 21 is connected to the high voltage side neutral point terminal 5. The voltage is an averaging circuit
It is input to 22 and averaged, and becomes a voltage proportional to the tube current (mA) having a waveform as shown by reference numeral 25. This voltage is digitized by the analog / digital (A / D) conversion circuit 24.

On the other hand, the time from when the tube current starts to flow to when it ends is detected as the X-ray emission time (s) and is also sent to the next stage as a digital signal.

Here, the method of detecting the tube current from the high-voltage side neutral point terminal 5 is illustrated, but a method of detecting the current flowing in the anode circuit of the X-ray tube with a hall element or the like, or the tube current with respect to a preset value, If it is corrected sufficiently, there is no practical problem even if this preset value is used as the tube current.

Reference numeral 11 is a tube voltage detection circuit, which has a circuit configuration as shown in FIG.

In FIG. 3, the voltage of the brush 2 of the autotransformer 1 is transformed by the insulating transformer 30 and converted into direct current by the rectifying / smoothing circuit 31. This DC voltage is input to the tube voltage precalculation calculation circuit 33, and converted into a voltage proportional to the tube voltage using the selected tube current signal 32 as a parameter. This tube voltage detection circuit 11
Is calculated so that the tube voltage value for each tube current is output by inputting the unloaded primary voltage of the main transformer 4, as shown in FIG. There is also a method of measuring the actual tube voltage value by connecting a voltage dividing resistor between both electrodes of the X-ray tube 7 for the tube voltage. The output of the tube voltage indication calculation circuit 33 is A / D converted by the analog / digital (A / D) conversion circuit 34 and sent to the next stage as a tube voltage signal (kV). The anode accumulated heat quantity (HU) of the X-ray tube 7 is calculated by the following equation in, for example, a two-peak rectification type high voltage device.

HU = tube voltage (kV) x tube current (mA) x time (s) (1) The total amount of heat accumulated in the anode per subject is the amount of heat during imaging and fluoroscopy per subject (( It can be calculated by the formula 1), and the total sum thereof can be expressed by the following formula.

As shown in FIG. 1, 12 is a calculation circuit, which is a tube current.X.
The signals of the line emission time detection circuit 10 and the tube voltage detection circuit 11 are used to perform the calculation of the formula (1) one after another for each X-ray emission, and the result is added one after another as shown in the formula (2). , The result of addition is stored in the first memory circuit 14. This addition is performed until the subject replacement signal 13 obtained from the identity number (ID No.) switching signal or the like is input. On the other hand, the calculation circuit 12 measures the time (t) from the previous subject replacement signal to the current signal, and when the subject replacement signal of this time is input, the addition shown in equation (2) is performed. Total amount of heat added up to that point Is divided by the measured time (t) to calculate the average amount of heat, and the result is sent to the comparison / control circuit 17. On the other hand, in the second memory circuit 15, the allowable average heat quantity of the X-ray tube is recorded.

In the comparison / control circuit 17, the average value of the allowable heat amount of the X-ray tube read by the X-ray tube type selection signal 16 from the second memory circuit 15 is compared with the average heat amount of the calculated result, and this time. If the average amount of heat for the subject exceeds a predetermined fixed value lower than the allowable value, a notice display 18 is given, and if it exceeds the allowable value, an X-ray radiation interlock signal 19 is generated. . It is also possible to display the ratio of the average calorific value of the calculation result and the allowable value in%, and this method is also an effective notice means for the operator.

If a warning is displayed, a warning will be issued to start a diagnosis of the next subject by taking a short rest time for subsequent use, and if the X-ray emission is interlocked, a slightly longer rest time may be given. The interlock is released by placing it,
Control so that it can be used again. It is also possible to display these required pause times.

The calculation and control of the calculation circuit 12, the first storage circuit 14, the second storage circuit 15, and the comparison / control circuit 17 can be easily realized by using the control of a microcomputer or the like.

As can be seen from the above description, according to this embodiment, the following effects can be obtained.

(1) Calculate the average value of the total calorific value of heat generated by the X-ray tube corresponding to the X-ray irradiation amount required to inspect one subject, and calculate the result A and the allowable calorific value of X-ray generation of the X-ray tube. When the calculation result A reaches a predetermined value C lower than the average value B, a first signal is generated, and when the calculation result A exceeds the average value B, a second signal is generated. Since the signal is generated, it is possible to continuously perform the number of times of imaging required for a series of diagnosis corresponding to the constitution of the subject within the range of the allowable value of the X-ray tube.

(2) According to the above (1), since information about the state of the average heat quantity of the X-ray tube can be sequentially provided to the operator, some pause is provided in the diagnosis time between the subject and the next subject. It is possible to avoid a diagnosis interruption due to an abrupt operation of the temperature limiter caused by no consideration of operation such as the above, or a diagnosis interruption due to a sudden tube damage.

(3) The first signal in (1) above has a predetermined time T ₁
If X-ray emission is not restarted during
By providing means for canceling the signal of _{No. 2 when} the X-ray emission is not restarted for a predetermined time T ₂ longer than the predetermined time T ₁ , the anode accumulated heat quantity is monitored with such a simple structure. Therefore, it is possible to prevent a load exceeding the anode accumulated heat capacity of the X-ray tube from being applied to the X-ray tube.
The life of the X-ray tube can be extended.

The present invention has been specifically described above based on the embodiments.
It is needless to say that the present invention is not limited to the above-mentioned embodiments and can be variously modified without departing from the scope of the invention.

For example, when a signal similar to the first signal of the above-described embodiment reaches each predetermined value Cn of a plurality of stages, a predetermined signal is generated for each stage, and these predetermined signals are generated by each unit of the X-ray apparatus. It can also be used to control

For example, the first signal or a plurality of predetermined signals can be used as a control reference signal for an injection operation of a contrast agent or the like.

〔The invention's effect〕

As described above, according to the present invention, the following effects can be obtained.

(1) In an X-ray device used for digestive system diagnosis, cardiovascular system diagnosis, etc., calculate the average value of the total calorific value of X-ray tube heat generation corresponding to the X-ray irradiation amount required to inspect one subject. Then, the calculation result A is compared with the average value B of the allowable X-ray generated heat of the X-ray tube, and the calculation result A is a predetermined value C lower than the average value B.
When the first signal is reached, or each predetermined value in multiple stages
When Cn is reached, a predetermined signal is generated at each stage, and when the calculation result A exceeds the average value B, a second signal is generated. It is possible to continuously perform imaging necessary for a series of diagnoses corresponding to the constitution of the subject.

(2) From the above (1), since it is possible to sequentially provide the operator with information regarding the state of the average calorific value of the X-ray tube, some pause is provided in the diagnosis time between the subject and the next subject. It is possible to avoid the interruption of the diagnosis due to the sudden operation of the temperature limiter caused by the lack of consideration of the operation such as the above, and the interruption of the diagnosis due to the sudden tube damage.

(3) When the first signal in (1) or each predetermined value Cn of a plurality of steps is reached, X-ray emission of each predetermined signal of each step is not restarted for a predetermined time T _1. When the X-ray emission is not restarted for a predetermined time T ₂ longer than the predetermined time T ₁ , the second signal is released, and the second signal is released by a simple structure. Since the amount of heat can be monitored and a load exceeding the anode accumulated heat capacity of the X-ray tube can be prevented from being applied to the X-ray tube, the life of the X-ray tube can be extended.

[Brief description of drawings]

1 is a block diagram showing a schematic configuration of an X-ray apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a tube current / X-ray emission time detection circuit shown in FIG. FIG. 3 is a block diagram showing the configuration of the tube voltage detection circuit shown in FIG. 1, and FIG. 4 is a diagram showing tube voltage characteristics. In the figure, 2 ... Brush, 3 ... X-ray switch, 5 ... High-voltage side neutral point terminal, 10 ... Tube current / X-ray emission time detection circuit, 11
...... Tube voltage detection circuit, 12 ...... Calculation circuit, 14 ...... First memory circuit, 15 ...... Second memory circuit, 17 ...... Comparison / control circuit, 18
…… Preliminary display, 19 …… X-ray radiation interlock signal.

Claims (2)

[Claims] 1. X-ray tube voltage, X-ray tube current, X-ray load time and X-ray
An X-ray apparatus configured to prevent an overload from being applied to the X-ray tube by calculating the remaining amount of heat accumulated in the anode of the X-ray tube from the X-ray emission stop time is used to inspect one subject. A calculation means for calculating an average value of the total heat generation amount of the X-ray tube corresponding to the required X-ray irradiation amount, and a calculation result A of the calculation means.
And a comparison means for comparing the average value B of the permissible X-ray generated heat of the X-ray tube, and a first signal when the calculation result A reaches a predetermined value C lower than the average value B, or a plurality of steps. An X-ray apparatus comprising means for generating a predetermined signal when each of the predetermined values Cn is reached, and for generating a second signal when the calculation result A exceeds the average value B. 2. X-ray tube voltage, X-ray tube current, X-ray load time and X-ray
An X-ray apparatus configured to prevent an overload from being applied to the X-ray tube by calculating the remaining amount of heat accumulated in the anode of the X-ray tube from the X-ray emission stop time is used to inspect one subject. A calculation means for calculating an average value of the total heat generation amount of the X-ray tube corresponding to the required X-ray irradiation amount, and a calculation result A of the calculation means.
And a comparison means for comparing the average value B of the permissible X-ray generated heat of the X-ray tube, and a first signal when the calculation result A reaches a predetermined value C lower than the average value B, or a plurality of steps. Means for generating a predetermined signal when reaching each predetermined value Cn, and generating a second signal when the calculation result A exceeds the average value B, and the first signal or each of the steps corresponding to each step. the predetermined signal, while the X-ray radiation for a predetermined time T ₁ is released if it is not restarted, the second signal is the predetermined time T ₁
An X-ray apparatus, characterized in that it comprises means for releasing if X-ray emission has not been restarted for a longer predetermined time T ₂ .