JPH0160919B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a diagnostic X-ray television apparatus capable of performing fluoroscopic diagnosis and photographic diagnosis, and particularly to a diagnostic X-ray television apparatus capable of rapidly performing fluoroscopic diagnosis. [Technical Background of the Invention] In general, diagnostic X-ray television equipment is capable of fluoroscopic diagnosis and photographic diagnosis of a subject, and is usually a bifocal type that can select either a large focus or a small focus. X-ray tubes are used. In addition, such equipment uses a large
Since short-time imaging is performed in which the amount of radiation is emitted in a short period of time, the sharpness is reduced, but the X-ray tube has a large focal point that allows for a large tube current and tube voltage. Furthermore, in fluoroscopic diagnosis, the tube current and tube voltage are suppressed compared to the large focal point, and a small focal point is used, which allows only a small X-ray intensity to be obtained, but which has high sharpness. Incidentally, X-ray photography is performed when a desired image is displayed during fluoroscopic diagnosis, so in order to improve diagnostic efficiency, the image should be displayed on the monitor immediately after operating the fluoroscopic switch in the fluoroscopic diagnosis. It is desirable that the information be displayed in However, due to the thermal inertia of the cathode heating filament of the X-ray tube, it takes a considerable amount of time to raise the temperature of the filament, and X-rays are irradiated a predetermined time after the fluoroscopy switch is operated. , I had a condition that made it difficult to obtain images promptly at the time of diagnosis. Therefore, as a solution to the above problem, the first
There is a diagnostic X-ray television apparatus configured as shown in the figure. That is, in the diagnostic X-ray television apparatus shown in FIG.
The respective contacts 3 and 4 are set to a closed state by the control circuit 5. At this time, in the small focus fluoroscopy filament 7 and the large focus imaging filament 8 of the X-ray tube 6, 2 The next output is passed through resistors 10 and 11 having resistance values corresponding to the respective preheating levels of the fluoroscopic preheating circuit 1 and the imaging preheating circuit 2, and further to the filament transformer 1.
No. 2 fluoroscopy transformer 12A and imaging transformer 12B
applied via. Therefore, at this point, the fluoroscopy filament 7 and the imaging filament 8 are preheated. Then, when a see-through switch (not shown) is turned on at time _t11 shown in FIG. The resulting secondary output is converted into a main heating output for fluoroscopy through the main heating circuit 13, and is applied to the fluoroscopy filament 7 of the X-ray tube 6 via the fluoroscopy transformer 12A of the filament transformer 12. As a result, the temperature of the fluoroscopy filament 7, which has been preheated by the fluoroscopy preheating circuit 1 and is at the fluoroscopy preheating level _A1 , gradually rises, and the temperature
The visibility level A ₂ is reached at t ₁₂ . At this point, the voltage supplied from the high-voltage transformer 17 via the rectifier 16 is already applied between the anode 14 and cathode 15 of the X-ray tube 6, so the fluoroscopic enhancement level
At time _t13 when the cathode 15 reaches the vicinity of _A2 , thermionic electrons are emitted from the cathode 15 toward the anode 14, and X-rays under transparent conditions are emitted from the thermionic collision point (focal point) on the anode 14. The fluoroscopic image signal will be extracted at time _t13 and the image will be displayed on the TV monitor. Note that during fluoroscopic diagnosis, when the main heating circuit 13 is activated under the control of the control circuit 5, the contacts 3 of the fluoroscopic preheating circuit 1 are opened, and when the main heating circuit 13 is activated during radiographic diagnosis, the contact 3 of the fluoroscopic preheating circuit 1 is opened under the control of the control circuit 5. The contacts 4 of the heating circuit 2 are opened,
This prevents multiple circuits from being activated at the same time. As mentioned above, in the apparatus shown in FIG. 1, when the main power is turned on, the fluoroscopy filament 7 is heated to the fluoroscopy preheating level A ₁ by the fluoroscopy preheating circuit 1.
is given. Then, at time _t11 , the fluoroscopy switch is turned on and the main heating circuit 13 is activated to heat the fluoroscopy filament 7. In this case, the temperature of the fluoroscopy filament 7 rises slowly due to the thermal inertia of the filament. For some reason, the perspective level
It takes time t ₁₂ - t ₁₁ to reach A ₂ , and it takes time t ₁₃ - t ₁₁ to obtain a fluoroscopic image signal. Furthermore, even if the shooting switch is turned on at time t ₂₁ ,
Since it takes time to switch from the fluoroscopy condition to the imaging condition, imaging becomes possible at time _t22 . However, the imaging ends at time _t23 , and the period from time _t23 to time _t24 is the switching time from imaging to fluoroscopy. In this way, it takes time t ₁₃ - t ₁₁ from turning on the fluoroscopy switch until the state is ready for fluoroscopic diagnosis, and this time causes unnecessary waiting time for the patient during diagnosis. However, it causes mental anxiety, and it is desired to shorten it in order to improve diagnostic efficiency. Therefore, as a method to solve this problem, the fluoroscopic preheating level A ₁ by the fluoroscopic preheating circuit 1 is set to a level close to the fluoroscopic level A ₂ (the fluoroscopic preheating level A ₃ as shown in FIG. 2; A ₂ > A ₃ > A ₁ ) can be considered. According to this method, the heating rise time of the fluoroscopy filament 7 is shortened, so
The above problem will be resolved. However, the imaging filament 8, which has been fully heated by the main heating circuit 13 during imaging diagnosis, is thermally affected by the fluoroscopy filament 7, which has been preheated to a level higher than the fluoroscopy preheating level _A1 . This results in
The imaging filament 8 becomes a double focal point, and the X-ray exposure required during imaging diagnosis is not performed appropriately, resulting in a problem that imaging diagnosis cannot be performed normally. [Object of the invention] The present invention was made based on the above circumstances, and
The purpose of this is to
To provide a diagnostic X-ray television apparatus capable of performing a fluoroscopic diagnosis immediately after turning on a fluoroscopy switch, and also capable of normally performing a photographic diagnosis. [Summary of the Invention] A diagnostic X-ray television apparatus according to the present invention comprises:
In a diagnostic X-ray television apparatus using a focus type X-ray tube having a focus for fluoroscopic diagnosis and a focus for imaging diagnosis, an apparatus for preheating a fluoroscopy filament used for cathode heating of the fluoroscopic diagnosis focus of the X-ray tube. a fluoroscopic preheating circuit in which a high preheating level and a low preheating level are set; a radiographic preheating circuit that preheats a radiographic filament used for cathode heating of a focal point for radiographic diagnosis of the X-ray tube; and a main heating circuit which performs main heating of the filament for radiography to enable fluoroscopic diagnosis and radiographic diagnosis, and in which the main heating level for fluoroscopy and the main heating level for radiography are set, and the above-mentioned preliminary heating for fluoroscopy during standby for fluoroscopic diagnosis. The circuit is started at a high preheating level and the preheating circuit for imaging is started, and the main heating circuit is started at the main heating level for fluoroscopy in order to main-heat the filament for fluoroscopy during fluoroscopy diagnosis, and the main heating circuit is started at the main heating level for fluoroscopy during fluoroscopy diagnosis. an X-ray tube filament heating circuit comprising: a control circuit that starts the fluoroscopic preheating circuit at a low preheating level; and a control circuit that starts the main heating circuit at the imaging main heating level to main-heat the imaging filament; In preparation, the fluoroscopic filament of the X-ray tube is preheated to a high level before performing fluoroscopic diagnosis, and the fluoroscopic filament is preheated to a low level after fluoroscopic diagnosis is completed, so that the radiographic diagnosis can be performed normally. Moreover, the waiting time during fluoroscopic diagnosis is greatly reduced. [Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIG. In FIG. 3, the same parts as those in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted, and only the different parts will be explained here. In FIG. 3, 18 is a see-through preheating circuit in which a high preheating level C ₁ and a low preheating level C ₂ are set. This see-through preheating circuit 18 has contact points 19
The resistor 22 is configured to be set to a low resistance value when the contact 20 is closed, the contact 21 is closed, and the contact 21 is opened, thereby setting the high preheat level _C1 . Further, when the contact 19 is closed, the contact 20 is opened, and the contact 21 is closed, the resistor 22 is set to a high resistance value, and thereby the low preheat level C ₂ is set. It's becoming like that. Here, the control circuit 23
When the main power is turned on, the transparent preheating circuit 18
is activated at a high preheating level C ₁ and the imaging preheating circuit 2 is activated. When the fluoroscopy switch and the imaging switch are turned on, the fluoroscopy preheating circuit 18 and the imaging preheating circuit 2 are activated. The main heating circuit 13 is controlled to be stopped and the main heating circuit 13 is started. Furthermore, when transitioning from fluoroscopic diagnosis to imaging diagnosis, the control circuit 23 controls the main heating circuit 13 to stop starting when the fluoroscopy switch is turned on, and the fluoroscopic preheating circuit 18 is set to a low preheating level C _{2 .} control to start up. Here, the high preheating level C ₁ of the fluoroscopic preheating circuit 18 is a fluoroscopic level C ₃ that enables fluoroscopic diagnosis, which will be described later.
The low preheat level _C2 is the preheat level close to
This is a preheating level set so that the photographic filament 8 does not become bifocal or the like. Next, the setting of specific values for the above-mentioned levels C ₁ , C ₂ , and C ₃ will be described. High preheating level C ₁ : The fluoroscopic preheating circuit 18 is set so that the fluoroscopic current is 0.2 mA (approximately the same condition as the filament life being 0.01 mA or less). In this case, when setting the fluoroscopic current to 0.01 mA during fluoroscopic diagnosis, the heating circuit 13 is used. In addition, the current
The condition of 0.01 mA is diagnostically insufficient dose. Low preheating level C ₂ : The fluoroscopic preheating circuit 18 is set so that the fluoroscopic current is 0.01 mA or less (that is, the amount of X-rays from the fluoroscopic focus during imaging diagnosis is 0). Fluoroscopic level C ₃ : Set by the main heating circuit 13 so that the fluoroscopic current can be set between 0 and 4 mA during fluoroscopic diagnosis. In addition, the tube voltage according to the Japanese Industrial Standards (JIS),
Table 1 shows the adjustment range of tube current.

〔Effect of the invention〕

As described above, in the present invention, in a diagnostic X-ray television apparatus capable of performing fluoroscopic diagnosis and radiographic diagnosis, the fluoroscopy filament of the X-ray tube is preheated to a high level before performing fluoroscopic diagnosis. The diagnostic X-ray television apparatus is configured to preheat the fluoroscopic filament at a low level once the fluoroscopic filament is finished, so that the diagnostic X-ray television apparatus can perform imaging diagnosis normally and can significantly shorten the waiting time during fluoroscopic diagnosis. Can be provided.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing a conventional diagnostic X-ray television apparatus, FIG. 2 is a timing chart showing the operation sequence of the apparatus shown in FIG. 1, and FIG. 3 is a diagram of a diagnostic X-ray television apparatus according to the present invention. FIG. 4 is a configuration diagram showing one embodiment, and a timing chart showing the operation sequence of the same embodiment. 2... Imaging preheating circuit, 6... X-ray tube, 7... Fluoroscopic filament, 8... Imaging filament, 9...
Heating transformer, 12...Filament transformer, 1
3... Main heating circuit, 14... Anode, 15... Cathode, 17
...High voltage transformer, 16... Rectifier, 18... Transparent preheating circuit, 23... Control circuit.

Claims (1)

[Claims] 1. In a diagnostic X-ray television apparatus using a multifocal type X-ray tube having a fluoroscopic diagnostic focus and a radiographic diagnostic focus, preheating the fluoroscopic filament used for cathode heating of the fluoroscopic diagnostic focus of the X-ray tube. a radiographic preheating circuit for preheating a radiographic filament used for cathode heating of a focal point for radiographic diagnosis of the X-ray tube; A main heating circuit that performs main heating of the filament for fluoroscopy and a filament for imaging to enable fluoroscopic diagnosis and radiographic diagnosis, and has a main heating level for fluoroscopy and a main heating level for imaging. The preheating circuit is started at a high preheating level, and the imaging preheating circuit is started. At the time of fluoroscopic diagnosis, the main heating circuit is started at the fluoroscopy main heating level in order to main heat the fluoroscopy filament, and the imaging is performed. X-ray tube filament heating consisting of a control circuit that starts the fluoroscopic preheating circuit at a low preheating level during diagnosis, and starts the main heating circuit at the imaging main heating level to main-heat the imaging filament. A diagnostic X-ray television device characterized by comprising a circuit.