JPH03283298A - Fluoroscopic photographing device - Google Patents

Abstract

PURPOSE:To shorten the time required for completing heating of a filament for large focus and shorten the time for snapshot by applying as a heating voltage for a filament for large focus a voltage larger than that corresponding to the current of a photographing tube at first, and changing the voltage to one corresponding to the set current of the photographing tube from the point at which heating is completed, so as to output an X-ray. CONSTITUTION:When a fluoroscopic photographing device is started for snapshot photography, focus is changed from small to large. At the same time a CPU 5b controls a filament heating circuit 5a so that the service maximum voltage (maximal heating level voltage) of a filament for large focus is applied from a filament heating transformer 3 to an X ray tube 1. When the temperature of the filament is raised to a fixed temperature corresponding to the current of a photographing tube, i.e., heating of the filament is completed, this is detected by a filament heating circuit 5a by that the current of the filament becomes a fixed value corresponding to the current of the photographing tube. When this is detected, the CPU 5b performs switching control of the voltage of the filament heating circuit 5a so that voltage (heating level voltage for photography) corresponding to a photographing current is applied from the filament heating transformer 3 to the X-ray tube 1 ; the CPU is then operated to output an X-ray.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention comprises an X-ray tube having two focal points, one large and one small.
The present invention relates to an X-ray fluoroscopic imaging device that performs fluoroscopy and quick photography by switching between two focal points.

[Prior Art] Conventionally, this type of device has been used to perform rapid photography using a large focus from a state of seeing through using a small focus until the filament for the large focus is completely heated (baked). There was one that was configured to wait, then output X-rays and take pictures.

In addition, when viewing using a small focus, the large focus filament is also heated to a small extent (not enough to cause X-rays to be output).
The camera is configured to perform preheating) to shorten the time it takes to complete heating of the large focus filament during quick-shot shooting, thereby shortening the quick-shooting time (the time from when starting quick-shot shooting until the shooting is completed). There was something.

[Problem to be solved by the invention]

However, the former of the above-mentioned conventional techniques (the method of waiting until the filament heating is completed) has problems such as a long snap-shot time and missed photo opportunities.

Furthermore, in the latter method (filament preheating method), since the filament for small focus and the filament for large focus are heated simultaneously, two filament heating circuit systems are required, which increases the cost. Also,
If the preheating is set too high to shorten the heating completion time, X-rays will be output from the large focus side during fluoroscopy, which will have a negative impact on fluoroscopy.On the other hand, if the preheating is small, the heating completion time will be too short. In addition, there was a problem that the effect of preheating was small.

An object of the present invention is to shorten the time to complete heating of a large focus filament with an inexpensive configuration, thereby shortening the time for quick shooting, and to reliably shorten the time to complete heating without affecting fluoroscopy. An object of the present invention is to provide an X-ray fluoroscopic imaging device that can perform

[Means to solve the problem]

The above object is to provide an X-ray fluoroscopic imaging apparatus that is equipped with an X-ray tube having two focal points, one large and one small, and performs fluoroscopy and rapid photography by switching between the two focal points. When taking snapshots using the large focal point, a heating voltage for the large focal filament is initially applied that is higher than a voltage corresponding to the set photography tube current, thereby heating the large focal filament. From the point of completion, this is achieved by providing an X-ray control means that switches and applies a voltage corresponding to the set imaging tube current to output X-rays.

[Effect]

The X-ray control means switches and controls the heating voltage of the large focus filament in the following manner when performing quick photography using the large focus from a state of seeing through using the small focus. That is, first of all, the voltage corresponding to the tube current set for photography (photography tube current) is not used, but the voltage larger than that, for example, the filament heating voltage corresponding to the maximum tube current at a large focus (use of a filament for a large focus). Maximum voltage) is applied,
The filament heating current is increased to raise the temperature of the large focus filament at once. Next, the fact that the temperature has reached a certain value, that is, the completion of heating the large focus filament, is detected using, for example, a filament heating current, and the filament heating voltage is switched to a voltage corresponding to the imaging tube current, and X-rays are output. , take pictures.

According to this, the time required to complete the heating of the large focus filament is shortened, and the time required for quick shooting is shortened. Further, the present invention does not preheat the large focus filament during fluoroscopy, that is, while heating the small focus filament. Therefore, the cost is reduced because two filament heating circuit systems are not required, and the preheating is not too large and does not affect the transparency; on the contrary, the preheating is small and the effect of preheating is reduced. Therefore, the heating completion time is definitely shortened.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the main parts of an embodiment of the X-ray fluoroscopic imaging apparatus according to the present invention. In the figure, 1 is an X-ray tube having 1112 focal points. 2 is a high voltage transformer that applies a tube voltage to the X-ray tube 1; 3 is a filament heating transformer that applies a filament heating voltage to the X-ray tube 1; these are in the same oil tank 4.
It is contained inside.

5 is an X-ray control device, which performs fluoroscopy similar to that in conventional devices;
Sets and controls shooting conditions. In addition, in the present invention, when performing quick photography using a large focus from a state of seeing through using a small focus, the X-ray control device 5 switches and controls the heating voltage of the large focus filament as follows. do. That is, first of all, it is not a voltage corresponding to the tube current (photography tube current) set for quick photography, but a voltage larger than that, in this case a filament heating voltage (large focus filament) corresponding to the maximum tube current at a large focus. maximum voltage used)
and increase the filament heating current. next,
Here, the filament heating current detects that the temperature has reached a certain value (set temperature), that is, the completion of heating the large focus filament, and the filament heating voltage is switched to a voltage equivalent to the imaging tube current, and the X-ray Output.

In order to switch and control the heating voltage of the large focus filament in this way, the X-ray control device 5 includes a filament heating circuit 5a and a CPU 5b. In this case, the filament heating circuit 5a generates a filament heating voltage,
And the filament heating current being energized is detected.

Further, the CPU 5 b controls the heating circuit 5 according to the settings of the operator.
In addition to controlling how much voltage corresponds to the filament heating voltage to be output from a, controlling the heating circuit 5a for switching the filament heating voltage when switching the focus of the X-ray tube 1, and further heating the filament for large focal points. The heating circuit 5a is controlled to detect the completion and to switch the filament heating voltage at that time.

Next, the present invention will be explained in detail with reference to FIG.

Figure 2 shows the switching operation of the focus of the X-ray tube 1 and the filament heating voltage according to the control command from the CPU 5b when performing quick photography using the large focus from the state of fluoroscopy using the small focus. 3 is a time chart showing the relationship between the switching operation and the switching operation. In FIG. 2, during fluoroscopy, a small focal point is selected and used, and the CPU 5b outputs a voltage corresponding to the fluoroscopy tube current (tube current set for fluoroscopy) from the filament heating circuit 5a. As a result, a filament heating voltage (fluoroscopic heating level voltage) corresponding to the fluoroscopic tube current is output from the filament heating transformer 3 to the X-ray tube 1.

When you activate snapshot shooting, the focus changes from small focus to large focus. At the same time, the CPU 5 b controls the filament heating circuit 5 a so as to apply the maximum voltage used for the large focus filament (maximum heating level voltage) from the filament heating transformer 3 to the X-ray tube 1 . This causes the filament temperature to rise at once. When the filament temperature reaches a constant temperature (set temperature) corresponding to the photo tube current, in other words, when the filament heating is completed, the filament heating circuit 5a indicates that the filament current has reached a constant value corresponding to the photo tube current. Detected in This is C
When the PU 5b detects this, the CPU 5b controls the filament heating circuit 5a to switch the voltage so as to apply a voltage corresponding to the imaging current (heating voltage for imaging) from the filament heating transformer 3 to the X-ray tube 1, and emit X-rays. Works to output.

By doing this, the time required to complete the heating of the large focus filament is shortened, and the quick-shooting time is shortened.

Here, the temporal change in the filament temperature rise during the filament heating will be explained with reference to Part 3, comparing it with the case of a conventional device.

The dotted line curve A in the figure shows normal heating, i.e., when performing fluoroscopy using a small focal point, switching to a large focal point for quick photography, and applying a filament heating voltage that can flow a filament current equivalent to the imaging tube current. Indicates filament temperature increase. In this case, the filament temperature gradually rises from room temperature to a constant temperature (set temperature) corresponding to the camera tube current, as shown by curve A.

In addition, for the dot-dashed line curved aperture, the filament for large focus should be preheated (energized) to a temperature that does not generate X-rays from the time of fluoroscopy using the small focus. Apply a filament voltage equivalent to the tube current,
This figure shows the increase in filament temperature in a method of increasing the filament temperature by supplying electricity to the filament (the filament preheating method described above). In this method, the filament temperature increases faster by increasing the filament temperature in advance.

The solid curve C shows the filament temperature increase according to the present invention. From this curve C, it can be seen that according to the present invention, the filament temperature reaches a constant temperature (set temperature) corresponding to the photo tube current faster than in the case of curve 49, that is, the time to complete heating of the filament is shortened. It can be seen that the time required for quick shooting is shortened.

Note that the present invention may be applied to the filament preheating method described above, and in this way, the time to complete filament heating and the time for quick copying can be further shortened.

[Effects of the Invention] According to the present invention, the maximum usable voltage of the large focus filament is applied immediately after the start of quick shooting, so the time to complete heating of the large focus filament can be shortened, and the quick shooting time can be shortened. There is an effect that it can be done.

Further, the large focus filament is not preheated during fluoroscopy, that is, while the small focus filament is being heated, and two filament heating circuit systems are not required, reducing costs. Moreover, there is also an effect that the heating completion time is reliably shortened without making the preheating too large and affecting the fluoroscopy, or the preheating being too small and the effect of the preheating being small.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the device of the present invention, and FIG.
The figure is a time chart for explaining the operation of the same device.
FIG. 3 is a graph illustrating the temporal change in filament temperature rise during filament heating in the apparatus of the present invention in comparison with that in the conventional apparatus. DESCRIPTION OF SYMBOLS 1...X-ray tube, 2...High voltage transformer, 3...Filament heating transformer, 5...Chi-ray control device (X-ray control means), 5a...Heating circuit, 5b...CPU . Figure 2

Claims (1)

[Claims] 1. In an X-ray fluoroscopic imaging device that is equipped with an X-ray tube having two focal points, one large and one small, and performs fluoroscopy and quick photography by switching between the two focal points, from a state in which fluoroscopy is performed using the small focal point. When taking snapshots using the large focal point, the heating voltage of the large focal filament is initially applied to a voltage higher than the voltage corresponding to the set photographing tube current, and when the heating of the large focal filament is completed. An X-ray fluoroscopic imaging apparatus characterized by comprising an X-ray control means that switches and applies a voltage corresponding to a set imaging tube current to output X-rays.