JPH01279600A - X-ray high voltage device - Google Patents

Abstract

PURPOSE:To enable the photographing-condition setting through two control scheme, by decomposing a set photographing tube current-time product into a maximum tube current and a minimum photographing time with the minimum photographing time so as not to be smaller than a predetermined value, and determining a tube current and a photographing time. CONSTITUTION:Set KV value and mAs value are sent to a main control device 13, and the mAs value is decomposed in principle into a maximum current mA and hence determined minimum photographing time sec by a microcomputer, etc., on the basis of rated data of X-ray tube 2, etc. As a result of decomposition, when the photographing time is less than a predetermined value, the tube-current mA value is decreased so that the photographing time is made equal to the predetermined value, and the mA value and the sec value are predetermined. The photographing time thus determined is supplied as command to a photographing-time timer 16, and an X-ray irradiation command is supplied from the timer 16 to an X-ray irradiation control circuit 15, and a thyristor switching signal for turning on the thyristor is provided therefrom to a high-voltage control circuit 12. At the same time, an X-ray tube voltage command and current command are provided from the main control device 13 to start the X-ray irradiation.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an X-ray high-voltage device used in medical X-ray photography, and more particularly to a single-phase, two-pulse type X-ray high-voltage device.

[Conventional technology]

The single-phase, two-pulse type X-ray high-voltage device rectifies the commercial AC power supply using a single-phase full-wave rectification method, and controls the imaging time in half-wave units by starting and cutting off exposure at the zero phase of the power supply voltage. It is widely used because it can use a single-phase power supply, has a simple configuration, and is therefore inexpensive. By the way, as methods for setting the X-ray imaging conditions, there is a three-control method in which the imaging tube voltage KV, imaging tube current mA, and imaging time sec are respectively set, and a two-control method in which the imaging tube voltage KV and imaging tube current time product mAs are set. A control method is known. The two-control method uses the mAs value set according to the subject and the X
Maximum tube current (m) that satisfies the radiation tube rating and X-ray high voltage equipment rating
This method automatically sets the time by dividing it into A and the shortest time sec, which has the advantage of maximizing the performance of the X-ray tube, etc., and obtaining an X-ray photograph with less blur due to subject movement. Inverter-type and tetrode-type X-ray high voltage equipment, which are more advanced than the single-phase 2-pulse method, use a 2-control method in addition to the 3-control method; The device has a three-control system. This is because in the single-phase two-pulse method, exposure can only be started and stopped at the zero phase of the power supply voltage, so the imaging time is an integral multiple of 10m5ec with a 50Hz power supply
With a 60Hz power supply, it is an integral multiple of 8.3m5ec, and the set mAs value cannot be resolved accurately, resulting in the problem that there is no linearity of the dose with respect to the set mAs value, so a two-control method was adopted. This is because it is difficult.

[Problem to be solved by the invention]

In this way, the conventional single-phase two-pulse X-ray high-voltage equipment uses a three-control system, so the two-control system maximizes the performance of the There is a problem in that the advantage of being able to take an X-ray photograph with less blur due to the movement of the object cannot be obtained. This invention provides an imaging strip 1'1' based on a two-control system.
- It is an object of the present invention to provide a single-phase two-pulse type X-ray high-voltage device that allows setting and benefits from the two-control type.

[Means for Solving the Problems 1] In order to achieve the above object, the X-ray high voltage apparatus according to the present invention includes means for setting the product of imaging tube voltage and imaging tube current time, and a means for setting the imaging tube current time product. means for determining the tube current and the imaging time by dividing the product into the maximum tube current and the shortest imaging time so that the minimum imaging time does not become shorter than a predetermined value, and the tube current and imaging time thus determined. and means for applying a high voltage to the X-ray tube in accordance with the set tube voltage. [Operation] Shooting conditions are set using a two-control method. That is, the imaging conditions are set by setting the imaging tube voltage and the imaging tube current time product. The set photographing tube current time product is decomposed into the maximum tube current and the shortest photographing time, but at this time, a restriction is added to the photographing time so that the shortest photographing time does not become shorter than a predetermined value. Since the imaging time does not become shorter than a predetermined value in this way, the imaging time with a large error in the case of the single-phase two-pulse method can be avoided, and highly accurate X-ray exposure becomes possible. This only avoids inconvenient imaging times, and other imaging times are the same as the normal two-control system, which maximizes the performance of the X-ray tube and reduces blur caused by subject movement. You can enjoy the advantage of the two-control system, which allows you to take X-ray pictures.

【Example】

Next, an embodiment of the present invention will be described with reference to the drawings. The figure shows one embodiment of the present invention. In this figure, an X-ray high voltage device 1 according to the present invention includes a high voltage generation transformer 11, a high voltage control circuit 12 including a power supply switch, etc. It consists of a main control device 13 consisting of a computer or the like, a panel 14 for displaying and setting imaging conditions, an X-ray exposure control circuit 1?815, and an imaging time timer 16. The thyristor opening/closing signal generated from the X-ray exposure control circuit 15 in synchronization with the zero phase of the power supply voltage turns on the power opening/closing thyristor of the high voltage control circuit 12, and power is supplied to the high voltage generation transformer 11. A high voltage boosted by the transformer 11 is applied to the X-ray tube 2, and the X-ray beam 4 is irradiated toward the subject 5 through the X-ray collimator 3, and the transmitted X-ray beam 4 is sandwiched between the aggravating paper 7. Enter the X-ray film 6 and make it glow. The operator (not shown) uses panel 1 for displaying and setting imaging conditions.
4, the photographing conditions using the two-control method are set. Although not shown in this panel 14, the photographing tube voltage KV
, a knob for setting the camera tube current time i'1 mA S, etc. are provided. Then, these set KV
The value and the mAs value are sent to the main controller 13, and the mAs value is determined by a microcomputer or the like based on the rated data of the X-ray tube 2, etc., and the maximum tube current mA and the shortest imaging time sec determined accordingly. However, as a result of this decomposition, the shooting time is a fixed value (32 m as described later).
5 (preferably) or less, the tube current mA is lowered so that the imaging time becomes the constant value, and the mA value and the sec value are determined again. The imaging time determined in this way is commanded to the imaging time timer 16, and this timer 16 issues an X-ray exposure command to the X-ray exposure control circuit 15, which instructs the high voltage control circuit 12 to turn on the radiation exposure. Cyrisk open/close signal is issued. At the same time, an X-ray tube voltage command and an X-ray tube current command are issued from the main controller 13, and a high voltage corresponding to the KV value set by the operator is applied to the X-ray tube 2. At the same time, a tube current corresponding to the mA value determined by the main controller 13 is passed, and X-ray exposure is started. Then, when the time corresponding to the sec value determined by the main controller 13 has elapsed, an X-ray cutoff command is issued from the timer 16, and the X-rays are cut off. Here, as the mA value that can be determined by the main controller 13, the 25% series values (for example, Table 1) that are commonly used in inverter type or tetrode type X-ray high voltage equipment are adopted. , and the mAs value that can be set in panel 14 is also the value of the 25% series (e.g., the second
Table) shall be adopted. Table 1 (Example of mA value of 25% series) 500, 400.320.250.200.160.1
25.100.30.63゜50, 40.32.25.
20.16.12.10mA Table 2 (25% series mA
Example of s value) 800, 630.500.400.320.250.2
00.160°125, 100. 80. 63. 5
0. 40. 32. 25°20, 16. 12.
10.8.0.6.3.5.0.4.0゜3.2.2
．． 5.2.0.1.6.1.2.0.8.0.6.0.
5 mAsThe advantage of such a 25% series is that when the shooting mAs is set as shown in Table 3 below, it can be freely decomposed into combinations of the shooting tube current mA and the shooting time sec. Table 3 (decomposition example in 25% series) mAs value mA value sec value 10mAs 500mA 20 +
n510+nAs 400mA 25
m510mAs 32(]++J 32
(31,3) m510mAs 250mA
40 m510mAs
200mA 50m510+
nAs 16 抛A 63 (62,5> m
510mAs 125mA 80
1510mAs 100mA
0.10 seclomAs 80m
A 0.12(0,125)seclomAs
63mA 0.16(0,158)s
eclomAs 50mA 0.20
seclomAs 40mA
0.25 seclomAs 32
mA 0.32 (0,313)seclomA
s 25mA 0.4se
clomAs 20mA 0.5
seclomAs 16n+A 0
．． 63(0,625)seclomAs 12m
A 0.83 (0,833)seelomAs
10mA 1.0 sec Then, when the mAs value is set on the panel 14, the main controller 13 converts this mAs value into both the rating of the X-ray tube 2 and the output rating of the X-ray high voltage device 1 itself. The maximum tube current mA is divided into the satisfactory maximum tube current mA and the shortest imaging time sec, but since the maximum tube current mA also changes depending on the X-ray tube voltage KV set at that time, the microcomputer etc. of the main controller 13 has Based on the stored data representing these relationships, the above decomposition is performed in consideration of these relationships, and the mA value and the sec value are calculated. By the way, in the single-phase two-pulse method, the imaging time is 10m5 (50H7) or 8.3m5 (60Hz>
The calculated shooting time is sec.
There is no other choice but to provide the timer 16 with an approximate value corresponding to the value. Approximate values corresponding to each shooting time in the 25% series are shown in Table 4 below. Table 4 (25% series shooting time and approximate values) Shooting time Approximate value Approximate value Error (50Hz) (60Hz) 10ms 10m5 8.3ms 1? ? g
12ms Ioms 8.3ms 31%
16+ns 20m5 16.7ms 25
%20m5 20m5 16.7ms 17%
:25m5 30m5 25.0ms 20%
3'2rns 30m5 33.3ms
6.3%40m5 40m5 41.7
ms 4.2￥150m5 50m5
50ms63ms 60m5 66.7ms
5.8%80m5 80m5 83.
3ms 4.1$0.10sec 0.10s
ec 0.10sec -0.12sec
0.12sec 0.12sec -0,16
sec 0.16sec 0.16sec
-0,20sec 0.20sec 0.20sec
c -0.25sec 0.25sec 0
．． 25sec -0,32sec 0.32s
ec 0.32sec -0640sec
0.40sec 0.40sec -0,50
sec 0.50sec 0.50sec
-0,63sec 0.63sec 0.63sec
c -0,80sec 0.80sec 0
．． 80sec -1.0sec 1.0sec
c 1.0sec -1,2sec
1.2sec 1.2sec -1.6s
ec 1.6sec 1.6sec
-2,0sec 2.0sec 2.0sec
- In Table 4, the error refers to the larger error between the original imaging time and its approximations at 50 Hz and 60 Hz. It can be seen that when approximating and irradiating using the pulse method, the error is 17% or more, which cannot be ignored. Therefore, in this embodiment, if the imaging time is 25 m5 or less as a result of decomposing the set mAs value, the main controller 13
A constant value of m5 is set, and the tube current mA value is calculated again based on this premise, and the mA value is lowered. Therefore, the shortest shooting time sec commanded from the main controller 13 to the timer 16 is 32 m5, and since the shooting time will not be shorter than that, the error is 6.3% or less from Table 4 above. , capable of highly accurate X-ray exposure. In this example, when the imaging time determined by decomposing the set mAs value was less than 25m5, the imaging time was set to a constant value of 32m5 and the mA value was changed accordingly. In such a case, the main controller 13 may be configured to display a message on the panel 14 to the effect that setting by the two-control method is not possible and to switch to setting by the three-control method. Furthermore, although an automatic exposure device (phototimer) is not used in the above description, it goes without saying that the present invention can also be applied to a case where an automatic exposure device is used. Furthermore, in the above general shooting,
Although the case of Butsky imaging is shown, it can of course also be applied to the case of fluoroscopic rapid photography using a fluoroscopic imaging stand. Further, in addition to the single-phase two-pulse type X-ray high voltage apparatus, the present invention can also be applied to a three-phase six-pulse type or three-phase 12-pulse type X-ray high voltage apparatus.

【Effect of the invention】

According to the X-ray high-voltage device of the present invention, since the imaging conditions can be set using a two-control system, the performance of the X-ray tube, etc. is f! - It is possible to perform X-ray photography to the maximum extent possible, and as a result, an X-ray photograph with less blur due to the movement of the subject can be obtained, and furthermore, operation by the operator is facilitated. Furthermore, an X-ray high-voltage device that uses a microcomputer requires only simple hardware changes, such as adding software and changing the operation panel surface, and can be implemented with a small economic burden. especially,
Since single-phase two-pulse type X-ray high-voltage equipment is inexpensive and widely used, it is of great significance that it is possible to set imaging conditions using the two-control type.

[Brief explanation of the drawing]

The figure is a block diagram of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... X-ray high voltage device, 11... High voltage generation transformer, 12... High voltage control circuit, 13... Main control device, 14... Imaging condition display and setting panel, 15...・
・X-ray exposure control circuit, 16...imaging time timer, 2.
...X-ray tube, 3...X-ray collimator, 4...X-ray beam, 5...subject, 6...X-ray film, 7...
・Intensifying screen.

Claims (1)

[Claims] (1) A means for setting the camera tube voltage and camera tube current time product, and a means for setting the camera tube current time product so that the shortest photography time does not become shorter than a predetermined value. means for determining the tube current and imaging time by decomposing them into two parts; a means for applying a high voltage to the X-ray tube according to the thus determined tube current and imaging time; and a means for applying a high voltage to the X-ray tube according to the set tube voltage. X-ray high voltage equipment.