JPS6333279B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an X-ray control device.

When performing X-ray photography, three elements are important as the main imaging conditions: tube voltage, tube current, and exposure time of the X-ray tube. In general X-ray photography, in order to make the degree of darkening of the X-ray film constant, the above-mentioned conditions are set for each subject and for each part to be imaged. In other words, an operator such as an X-ray technician uses the patient's irradiation record or chart to determine the medical condition,
Either the operator knows the physique, etc. and relies mainly on his own long experience, or he prepares a table of photographing conditions in advance and manually sets the photographing conditions based on it.

However, allowable load conditions or instantaneous ratings are determined for the X-ray tube equipment used, and imaging conditions must be set to satisfy these conditions. This resulted in damage to the X-ray tube and danger to patients. That is, even if the optimal imaging conditions are known based on the operator's experience, when actually performing X-ray exposure, the amount of power instantaneously applied to the X-ray tube exceeds the instantaneous rating. X
There was a problem in that the target surface of the tube was cracked, posing a danger to patients.

The present invention has been made in view of the above circumstances, and it minimizes the probability that an operator selects and sets imaging conditions in an overload state, and also prevents X-ray exposure in an overload state. The object of the present invention is to provide an X-ray control device that can prevent damage to the ray tube or danger to patients.

The present invention will be specifically explained below using Examples.

FIG. 1 is a block diagram showing one embodiment of the present invention. In this embodiment, an X-ray tube is used in which at least two focal points can be selected, that is, a large focal point and a small focal point, and among the signal lines, a thin line is a single signal line, a thick black line is a multi-signal line, and a thick white line is a multi-signal line. It is a binary signal line. In the figure, 1 is a tube voltage setting device;
2 is a tube current setting device, and 3 is an imaging time setting device (hereinafter referred to as
These are collectively referred to as each photographing condition setting device), and each includes a switch (for example, a momentary switch) 1a, 2a, 3a and a pull-up resistor 1.
b, 2b, and 3b, and the switch portion in particular is attached to an operation panel (not shown). The momentary switch remains on when the operator continues to press it, and turns off when the operator releases it. Reference numeral 4 denotes an X-ray tube focus selector, which is composed of a changeover switch 4a and a pull-up resistor 4b, and is connected to an X-ray tube device (not shown).When the switch 4a is off, the large focus of the X-ray tube is selected; is on, the small focal point of the X-ray tube is selected. This switch 4
A is also attached to the operation panel surface. The output signals of the setters 1 to 3 are applied to one input terminal of correspondingly arranged AND gate circuits 6A to 6C via inverters 5A to 5C, respectively. Reference numeral 7 denotes an oscillator, which outputs a frequency pulse signal of, for example, 200 Hz. The output signal of this oscillator 7 is applied to a frequency division counter 9 via an AND gate circuit 8. This frequency division counter 9 is configured to output, for example, an output obtained by dividing the output of the oscillator 7 by a factor of 100, that is, a frequency pulse signal of 2 Hz. The output signal of the frequency division counter 9 is commonly applied to the other input terminals of the three AND gate circuits 6A to 6C via an OR gate circuit 10. The OR gate circuit 10 is controlled by the output signal of an AND gate circuit 11 which has one input as the output signal of the oscillator 7. Moreover, the AND gate circuit 6A
The outputs of the counters 6C to 6C are applied to input terminals of three counters 12A to 12C arranged in correspondence with each other. Therefore, the counter (one of 12A, 12B, 12C) corresponding to the selected switch 1a, 2a, 3a in each of the imaging condition setters 1 to 3 is set to the frequency dividing counter 9 or the oscillator 7. An output is applied which will control the counter operation. Here, the counters 12A to 12C are serial (serial) in, parallel (parallel) out ring counters that generate a binary output corresponding to the number of counts and have the ability to count at least 20 pulses, for example. , it returns to 0 after the 20th one. 13A to 13
C is a tube voltage storage device, a tube current storage device, and
It is an imaging time storage device that stores multiple tube voltage values (KVp), tube current values (mA), and time values (SEC).
Digital values corresponding to are stored in an addressed manner. These stored digital values span, for example, 20 steps, and the digital values of the corresponding steps are sequentially accessed based on the output signals (for each pulse) of the counters 12A to 12C. By the way, each of these storage devices 13A to 13C is sequentially accessed by the output signals of the corresponding counters 12A to 12C, but before the start of access (that is, in the initial state), the minimum value It is designed to generate an output signal corresponding to. For example, the tube voltage is 5KVp, the tube current is 10mA, and the shooting time is
It is assumed that 0.01SEC is selected as the initial value. As mentioned above, the X-ray tube used here has two types of focus (large focus and small focus), so if the focus changes, the tube voltage value, tube current value, and imaging value that should be set will change. Since the time also needs to change accordingly, two types of storage devices must be prepared. If only one type of data is prepared, the operator may make a setting error and destroy the X-ray tube. In other words, taking tube current as an example, a small tube current is sufficient when selecting a small focal point, but the operator may create an illusion that a large focal point is selected and set a large current. This is because it is easy to cause but,
It is not always necessary to prepare two types of storage devices; for example, a storage device with a large storage capacity may be divided into a first stage and a second stage, and two types of data may be stored in each stage. Switching between the two types of data may be performed based on the output signal of the X-ray tube focus selector 4. That is, when the switch 4a of the selector 4 is off, the data stored for large focus can be selected, and when the switch 4a is on, the data stored for small focus can be selected.

The output signals of each of the storage devices 13A to 13C thus obtained are supplied to an X-ray tube device (not shown) as various setting signals. That is, the tube voltage setting signal _S2 is sent from the tube voltage storage device 13A, the tube current setting signal _S3 is sent from the tube current storage device 13B, and the shooting time setting signal _S4 is sent from the shooting time storage device 13C.
are respectively output and drive the X-ray tube device. Furthermore, these various setting signals S ₂ to S ₄ are applied to the displays 15A to 15C (these displays are attached to the operation panel surface) via display drive circuits 14A to 14C provided correspondingly. be done. Each of the display drive circuits 14A to 14C has a built-in decoder, and drives each of the displays 15A to 15C each having a plurality of sets of light emitting elements (for example, photodiodes) each having seven segments based on the decoded output signal. (so-called BCD-7 segment decoder/driver). Display devices 15A and 15
B can display a three-digit number, and each functions to display a tube voltage value and a tube current value. Further, the display 15C is capable of displaying a three-digit number and a decimal point (dot), and functions to display the shooting time. Reference numeral 16 denotes an X-ray tube instantaneous allowable load power storage device, which stores a digital value corresponding to the maximum allowable power applied to the X-ray tube for each set imaging time in the instantaneous allowable load characteristics of the X-ray tube device.

Here, an example of data stored in the X-ray tube instantaneous allowable load power storage device (hereinafter referred to as power storage device) will be described with reference to FIG. In the figure, the horizontal axis shows the imaging time (SEC) and the vertical axis shows the applied power to the X-ray tube (W x 10 ³ = KVp x mA x 10 ³ ). This is a representation of the instantaneous maximum load curve. In the case of steady rotation with large focus (2ro) in the same figure,
shows the case of small focus (1ro) steady rotation. Therefore, the power storage device 16 stores power values corresponding to each imaging time step along these load curves. In this case, it is recommended to provide two types of storage devices, one for large focal points and one for small focal points, or, if the storage device has a large storage capacity, to divide it into a first stage and a second stage, and store two types of data in each. Make it. Switching between the two types of data is performed based on the output signal of the X-ray tube focus selector 4. That is, for example, when the switch 4a of the selector 4 is off, the large focal point storage data can be accessed, and when the switch 4a is on, the small focal point storage data can be accessed. Incidentally, although the above description relates to steady rotation, data may be stored in the same manner for high speed rotation and may be switched using a selector. Moreover, this power storage device 1
6 outputs a signal based on the power value (maximum power) corresponding to the minimum imaging time (for example, 0.01 SEC) before being accessed, that is, in the initial state.

17 is the tube voltage setting signal _S2 and the tube current setting signal
This multiplier ₁₇ calculates the product of the set tube voltage (KVp) and the set tube current (mA), that is, the power value applied to the X-ray tube device, and A corresponding digital output signal is generated. The output signal of the multiplier 17 and the output signal of the power storage device 16 are compared by a digital comparator 18. The digital comparator 18 compares the respective output signals, and the multiplier 17
An output signal S ₁ is produced which is inverted when the output of the power storage device 16 exceeds the output of the power storage device 16 . This output signal
_S1 is applied to the X-ray tube device and is designed to inhibit (interlock) the X-ray exposure signal at an inverted level. Further, this output signal _S1 is applied to the other input terminal of an AND gate circuit 8 which serves as a control gate of the frequency division counter 9, and is also applied via an inverter 19 to an AND gate circuit whose one input is the output of the oscillator 7. It is also applied to the other input terminal of the gate circuit 11.

Next, the operation of the apparatus of the embodiment will be explained. In the following explanation, positive logic is used, and the power supply (+V) level is assumed to be the "1" level, and the ground level is assumed to be the "0" level. First, the operator is the patient (or subject)
It is selected whether to use the large focal point or the small focal point of the X-ray tube depending on the state of the For example, if the large focal point is selected, the switch 4a of the X-ray tube focus selector 4 may be turned off and a power switch or an imaging start button (not shown) may be pressed. Conversely, when selecting a small focus, switch 4 of the X-ray tube focus selector 4
All you have to do is turn on the power and turn on the power. Then, each storage device 13A to 1 is selected according to each selection mode.
3C and 16 desired data are selectively switched and made accessible. Next, tube voltage setting device 1
When the momentary switch 1a is pressed, a "1" level signal is applied to the AND gate circuit 6A via the inverter 5A, so the gate opens and the counter 12A starts operating. At this time,
If the output _S1 of the digital comparator 18 is set to the "1" level, the gate of the AND gate circuit 8, which uses the output of the oscillator 7 as one input, will be opened. The 200Hz output of the oscillator 7 is input to the frequency division counter 9 via the oscillator 7. Then, a 2 Hz pulse output is generated from the frequency division counter 9, and is inputted to the AND gate circuit 6A via the OR gate circuit 10. Therefore, the counter 12A is controlled to sequentially count by the 2 Hz pulse output from the frequency dividing counter 9, and generates a sequentially incremented pulse mode output at its output terminal, and the tube voltage storage device 13A.
access. Therefore, the tube voltage storage device 13A
outputs a tube voltage setting signal _S2 whose setting tube voltage value changes sequentially from a small value to a large value. Further, the display drive circuit 14A is driven by this tube voltage setting signal _S2 , and the tube voltage value is displayed on the display 15A.
Here, if the momentary switch 1a of the tube voltage setting device 1 is kept pressed, the counter 12A and the tube voltage storage device 13A will also continue to operate, so the output signal _S2 of the tube voltage storage device 13A will also change from time to time. Accordingly, the tube voltage value displayed on the display 15A also changes sequentially from a small value to a large value. Therefore, the operator can obtain the tube voltage setting signal _S2 by looking at the tube voltage value displayed on the display 15A and releasing the momentary switch 1a when the desired value is reached. Next, by pressing the momentary switch 2a of the tube current setting device 2, the counter 12B is operated, the tube current storage device 13B is accessed, and the tube current value, which changes from moment to moment, is displayed on the display 15B. In this way, the tube current setting signal S ₃ corresponding to the desired value of tube current is generated in the same manner as above.
can be obtained. Furthermore, when the momentary switch 3a of the shooting time setting device 3 is pressed, the counter 12
C operates, the photographing time storage device 13C is accessed, and a numerical value that changes over time is displayed on the display 15C. In this case as well, the momentary switch 3a can be released when the desired value is reached while watching the numerical value displayed on the display 15C. As a result, a photographing time setting signal _S3 corresponding to the desired photographing time is obtained. At this time, the power storage device 16 is accessed at the same time,
A signal regarding the allowable load power value corresponding to the set imaging time based on the characteristics shown in FIG. 2 is output.

Here, in the process of setting each imaging condition, the tube voltage setting signal S ₂ and the tube current setting signal S ₃ are multiplied by a digital multiplier 17, and from this multiplier 17, the signals are applied to the X-ray tube device. A signal corresponding to the power value is output. The output signal of the multiplier 17 and the output signal of the power storage device 16 are compared by a digital comparator 18.
That is, in the tube voltage setting stage, the tube voltage storage device 13A
The tube voltage setting signal S ₂ that changes with time and the output signal S ₃ based on the initial state of the tube current storage device 13B are output from the tube voltage setting signal S 2 that changes with time. The tube current setting signal S ₃ that changes with the tube current setting signal S 3 and the tube voltage setting signal S ₂ that has already been set in the previous stage are respectively multiplied,
It will be input to the comparator 18. Then, the output of the multiplier 17 (the power value applied to the X-ray tube device) and the output of the power storage device 16 (the allowable load power value corresponding to the imaging time in the initial state or the set imaging time) are combined. As a result of the comparison, multiplier 1
7 is within the range of the output of the power storage device 16, the output state of the comparator 18 does not change and remains at the "1" level, so there is no change in the display state of the indicators 15A to 15C. Does not occur. Therefore, the operator only needs to set all the imaging conditions while confirming that there are no changes in the states of the displays 15A to 15C, and then press the X-ray exposure switch (not shown) to perform the predetermined imaging. However, multiplier 17
If the output of the comparator 18 exceeds the output of the power storage device 16, the output _S1 of the comparator 18 will be inverted to the "0" level. This inverted signal S ₁ interlocks the X-ray exposure signal of the X-ray tube device, and at the same time, this inverted signal S ₁ causes one AND gate circuit 8 which receives the output signal of the oscillator 7 as one input. The gate of the AND gate circuit 11 is closed, and the gate of the other AND gate circuit 11 is opened. For this reason, the oscillator 7
The 200 Hz pulse output can be directly applied to each of the counters 12A to 12C without passing through the frequency division counter 9. Thus, for example, the tube voltage setting step (i.e.
When the momentary switch 1a in the tube voltage setting device 1 is kept pressed), the output S ₁ of the comparator 18
is inverted, the 200Hz pulse output signal of the oscillator 7 is applied to the counter 12A via the AND gate circuits 11 and 6A, and this causes the counter 12A to operate at high speed.
A is accessed at high speed. Therefore, the repetition rate of the tube voltage setting signal _S2 becomes extremely high, and the display 15A is thereby driven, so that the displayed tube voltage value changes rapidly. By visually observing the state of the display 15A, the operator can know that the set value exceeds the allowable load range. The counter 12A performs a high-speed counting operation, and when it reaches the maximum pulse mode (for example, the 20th pulse), it returns to the minimum pulse mode (for example, 0). Accordingly, the tube voltage storage device 1
The output of 3A is also the maximum value of the set tube voltage (e.g.
Set tube voltage minimum value (e.g. 150KVp) via
5KVp), and at the same time, the output of the multiplier 17 is also returned to within the allowable load range, and the output of the comparator 18 S ₁
also returns to the "1" level. As a result, the interlock of the X-ray exposure signal is released and the oscillator 7
The output signal is also applied to each of the counters 12A to 12C via the frequency division counter 9. After that, all you have to do is set the appropriate tube voltage value again. Similar operations are performed at the stage of setting the tube current and imaging time, but detailed explanation thereof will be omitted.

It goes without saying that after a predetermined photographing is completed, by pressing a reset button (not shown), each device returns to its initial state and becomes ready for the next photographing.

By the way, as mentioned above, if the oscillation frequency of the oscillator 7 is 200Hz and the 100x frequency dividing counter 9 is used, the change period during setting and display will be about 0.5 seconds, so the operator will have to adjust the displayed number. It can be sufficiently recognized, and since the change period is as fast as 0.005 seconds in an overload state, it is possible to quickly return the load to within the allowable load range. In this embodiment, the frequency of the oscillator 7 and the magnification of the frequency division counter 9 can be arbitrarily changed according to the operator's wishes.

According to the apparatus of the present invention described in detail above, a display that changes rapidly in the event of an overload condition is provided so that the condition can be easily recognized, and an interlock is applied to X-ray exposure. The probability of the operator selecting and setting imaging conditions under overload can be drastically reduced, and X-ray exposure under overload can be prevented, thereby preventing damage to the X-ray tube or danger to patients. can do. In addition, since the overload state can be determined and the operation to return to within the permissible range can be carried out at high speed, the operation time and, by extension, the photographing time can be shortened.

The present invention is not limited to the embodiments described above, and various modifications can be made without changing the gist thereof. For example, in the embodiment described above, by changing the frequency of the pulse signal applied to each counter 12A to 12C, the overload state is quickly returned to the allowable load state, but the configuration of this part is shown in FIG. You may change it as follows. That is, in place of the oscillator 7 of the embodiment described above, an oscillator 7' that generates an output pulse having a frequency of 1 or 2 Hz is provided, and the existing AND gate circuit 8, frequency division counter 9,
The OR gate circuit 10 and the AND gate circuit 11 are removed, and the output of the oscillator 7' is commonly applied to three AND gate circuits 6A to 6C for direct counter control. And newly each shooting condition setting device 1
Inverted signals from inverters 5A to 3 (inverters 5A to 5C)
Three AND gate circuits 20A to 20C are provided, each having one input of the output signal S ₁ which is inverted by the comparator 18.
An inverted signal (inverted by the inverter 19) is applied in common, and the output terminals of the AND gate circuits 20A to 20C are connected to the clear (CLR) terminals of the corresponding counters 12A to 12C, respectively.

With such a configuration, if the shooting conditions become overloaded while setting the shooting conditions, the comparator 18
The output of the inverter 19 is inverted and becomes the "0" level, and the exposure signal is interlocked, and the inverter 19
A "1" level signal is applied to the inputs of the newly installed AND gate circuits 20A to 20C. Therefore, any one of the counters 12A to 12C corresponding to the setting device being operated is cleared, and the output of the storage device in the output stage of the counter returns to the minimum value of the set shooting condition value group. Exactly the same effects as in the first embodiment can be obtained, such as the overload state being canceled and proper photographing conditions being settable. In this case, the output of the storage device corresponding to the cleared counter will instantly return to the minimum value, and the display will immediately change to the initial value display accordingly. It is possible to know that an overload condition has occurred by looking at the change in the display, and to take prompt action.

Further, by adding an alarm mechanism to the output terminal of the comparator 18 and configuring the comparator 18 to issue an alarm using an inverted signal, the overload state can be determined more reliably.

In the above embodiment, all processing is digital processing, but a configuration may be adopted in which part or all of the processing is replaced with analog processing.

Furthermore, when the X-ray tube to be used has two or more types of focal points, it is necessary to change the configuration of the X-ray tube focus selector and the contents of the stored data in each storage device accordingly; It goes without saying that when a single-focus X-ray tube is used, an X-ray tube focus selector is not necessary, and one type of data stored in each storage device is sufficient.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram of instantaneous permissible load characteristics of an X-ray tube device,
FIG. 3 is a block diagram showing another embodiment of the present invention. 1...Tube voltage setting device, 2...Tube current setting device, 3
...Photographing time setting device, 4...X-ray tube focus selector,
5A to 5D, 19...Inverter, 6A to 6C,
8, 11...and gate circuit, 7...oscillator,
9... Frequency division counter, 10... OR gate circuit,
12A to 12C... Counter, 13A... Tube voltage storage device, 13B... Tube current storage device, 13C...
... Shooting time storage device, 14A to 14C... Display drive circuit, 15A to 15C... Display, 16...
power storage device, 17... multiplier, 18... comparator;

Claims (1)

[Claims] 1 A tube voltage setting device, a tube current setting device, and an imaging time setting device that can individually set X-ray imaging conditions, and a tube whose stored information is accessed at a predetermined period based on the output signal of each of the imaging condition setting devices. a voltage storage device, a tube current storage device, an imaging time storage device, a display means for displaying the accessed storage contents for each of the imaging times based on an output signal of the imaging condition storage device, and an earlier imaging condition storage device. means for determining the power value applied to the X-ray tube based on the output signal of the device; and overload state determining means for generating a warning signal when the power value exceeds the instantaneous permissible load range of the X-ray tube used. , a means for prohibiting the exposure signal of the X-ray tube based on the warning signal of the overload state determining means, and at least one of the plurality of stored information of the first-stage imaging condition storage device in response to the signal for prohibiting the first-stage exposure.
1. An X-ray control device comprising: means for accessing one stored information at a cycle different from the predetermined cycle, and then accessing and outputting only the predetermined stored value.