JPH079357Y2 - X-ray fluoroscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an X-ray fluoroscopic imaging apparatus, and more particularly to automatic setting of a backup time of a photo timer from fluoroscopic conditions for a model equipped with a photo timer.

(B) Prior art As an automatic setting method of shooting conditions in fluoroscopy,
Conventionally, a method has been adopted in which the imaging condition is calculated from the fluoroscopic condition.

The X-rays are blocked by a signal from an X-ray automatic exposure device (phototimer), and the shooting time functions as a backup of the phototimer among the automatically set shooting conditions (tube voltage, tube current, shooting time).

This shooting time is fixed invariably in the past.
It is set to the maximum allowable shooting time of the subject to be shot. In addition, the value of the tube current is set to the maximum value that can flow during the imaging time within the tolerance of the X-ray tube rating with respect to the tube voltage related by the fluoroscopic condition.

(C) Problems to be solved by the invention The fact that the shooting time is fixed and invariable means that
If the radiation is blocked, it means that the rating of the X-ray tube is not being used effectively, while in the case of a subject that actually requires a long X-ray exposure time, it is nevertheless given that The X-rays were blocked during the back-up time, which resulted in a photograph in which an appropriate film density could not be obtained.

Therefore, the purpose of the present invention is to make effective use of the rating of the X-ray tube at a value close to the value expected to be cut off by the photo timer, that is, to shorten the X-ray exposure time. An object of the present invention is to provide an X-ray fluoroscopic imaging apparatus capable of obtaining a photograph with less blur due to movement of a subject.

(D) Means for Solving the Problems The above-mentioned purpose is to optimally control the fluoroscopic tube voltage based on the X-ray intensity of the object under fluoroscopy so that the brightness of the fluoroscopic image displayed on the TV monitor becomes a predetermined value. Fluorescence brightness control unit, imaging control unit that sets imaging tube voltage, imaging tube current, and imaging time at the time of imaging, X-ray when the transmission X-ray amount of the subject is detected and the transmission X-ray amount reaches a predetermined value. In an X-ray fluoroscopic imaging apparatus including a phototimer for blocking exposure, an optimum fluoroscopic tube voltage corresponding to different thicknesses of a subject, an optimum imaging tube voltage substantially corresponding to the subject thickness, and the subject thickness Each of the memories for storing data relating to the current product of the imaging tube current corresponding to, and the corresponding object thickness is read out from the memory based on the optimum fluoroscopic tube voltage by the fluoroscopic brightness control unit during fluoroscopy. Corresponding to each A means for similarly obtaining the optimum tube voltage and tube current time product from the memory and obtaining a constant multiple of the obtained tube current time product under the maximum tube current according to the X-ray tube rating. The above-mentioned setting is provided with a calculating means for disassembling each in the shortest time to obtain each, and a means for setting the photographing tube current, the photographing time and the optimum photographing tube voltage obtained by the calculating means in the photographing control section as photographing conditions. This is achieved by setting the shooting time as the backup time of the photo timer.

(E) Action The relationship data between the fluoroscopic condition and the shooting condition for various subject thicknesses is stored in advance, and the tube voltage and the tube current time product are obtained from the stored data at the time of shooting, especially the tube current time product. Stores the data by the measured values so that the obtained maximum tube current and the shortest time of the X-ray tube rating are obtained for the tube voltage obtained at the same time.

(F) Embodiment A preferred embodiment of the present invention will be described with reference to the drawings.

For convenience of explanation, a conventional automatic setting method will be described with reference to FIG. As shown in the curve in the figure, the rating of the X-ray tube allows a larger current to flow when the tube voltage is constant and the time is shorter.

Therefore, the tube current mA1 at the imaging time T1 which is a constant value is set for the tube voltage (KV1 in the figure) related from the fluoroscopic condition. However, shooting time T1
Since it is constant, there is no choice but to set the longest allowable time for the subject to be photographed.

This means that the X-ray cut-off by the normal photo timer is performed in the time T2, which is shorter than the imaging time T1, the load applied to the X-ray tube is small, and it can be said that the rating of the X-ray tube is fully utilized. Absent.

Therefore, it should be noted that in the figure, the back-up time T1 of the photo timer is set to T4 as the set value on the short time side (left side).
Is that it is possible to choose. At this time, the tube current at T4 (mA2 () mA1) can be passed, and mA1 × T2 = mA2
At the photographing time T3, which is × T3, the photo timer emits a cutoff signal, indicating that the photographing for a shorter time (T3 (T2) can be set.

In this way, the shooting time is always set by X with the photo timer.
It is an operation purpose of the present invention to bring the radiation exposure time close to the time.

Next, FIG. 1 showing one embodiment of the present invention will be described.

1 is an imaging control unit, 2 is a fluoroscopy control unit, 3 is a high voltage generator, 11
Is a microcomputer and 12 is a memory, and these constitute an X-ray high voltage apparatus. In addition, 4 is an X-ray tube, 5
Is a subject, 6 is a film holding device, 7 is an image intensifier (II), 8 is a television camera and its control unit, 9 is a monitor, and 10 is a signal processing unit (perspective brightness control unit) for adjusting the perspective brightness. .

In this embodiment, the imaging conditions as well as the fluoroscopic conditions are measured in advance and the related data are stored in the memory 12.

FIG. 2 shows the relationship between subject thickness and perspective conditions. In advance, using the human equivalent phantom, the fluoroscopic tube voltages A, B, and C at the subject thicknesses tA, tB, and tC, respectively.
Is obtained by the transparent brightness automatic adjuster 10. a, b, and c are fluoroscopic tube voltages A to C when the fluoroscopic tube current is changed from 2 mA to 1 mA.
Equivalent to.

FIG. 3 shows the relationship between the subject thickness and the tube voltage. This relational data can be set arbitrarily.

FIG. 4 shows the relationship between subject thickness and tube current time product. This relationship shows that after setting the tube voltage A'in FIG. 3 for a certain thickness tA, the tube current-time product (mAs) A "at which the proper concentration is obtained is measured by actually photographing. ing.

At least the relational data shown in FIGS. 2 to 4 are stored in the memory 12.

In actual use, when fluoroscopy is performed, the subject thickness is obtained from the fluoroscope voltage and the fluoroscope current from FIG. 2, and the tube voltage and the tube current time at that subject thickness are obtained from FIGS. 3 and 4. Each product is obtained.

Here, the obtained tube current-time product mAs is multiplied by a fixed value in order to function as a back-up of the photo timer. Then, the calculation according to FIG. 5 is performed so that the shortest imaging time can be obtained under the maximum tube current according to the X-ray tube rating. M is a constant. The tube current time product is multiplied by a certain amount to make it a little larger.

If the relationships between FIG. 6 and FIGS. 3 and 4 are associated, for example, the tube voltage A ′ at the subject thickness tA corresponds to KV1 in FIG. 6, and the value of A ″ in FIG. Corresponds to mA1 × T2 in FIG. 6, and the back-up obtained by multiplying the value of A ″ by a certain amount corresponds to mA2 × T4.

The dotted line in FIG. 1 shows the flow of data according to the present invention. The computer 11 obtains data from the perspective control unit 2 and refers to the memory 12 using this data as a key.
Necessary data is taken in and calculation is performed, and the target data is output to the photographing control unit 1. Details of each data are as described above.

Further, since the imaging time obtained by the present invention is obtained by predicting the interruption time by the photo timer, the photo timer is suitable when the X-rays directly enter the X-ray detector during X-ray exposure. If a cutoff signal is to be issued earlier than the shooting time, it is necessary to add a function to block it.

(G) Effect According to the present invention, it is possible to change the setting of the shooting time according to the subject thickness, prevent X-rays from being blocked earlier in the thick subject than when set by the photo timer, and in the thin subject. It is possible to shoot for a short period of time, there is little blurring due to the motion of the subject, and an effect that a photograph of appropriate density can be obtained is obtained in any case.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of the present invention.
Fig. 2 shows the subject's thickness perspective tube voltage characteristic diagram, Fig. 3 shows the subject's thickness / camera tube voltage characteristic diagram, Fig. 4 shows the subject's thickness / tube current time product characteristic diagram, and Fig. 5 shows the X-ray tube rating. A curve / shortest time characteristic diagram, and FIG. 6 is an X-ray tube rated curve / tube current characteristic diagram. 1 is an imaging control unit, 2 is a fluoroscopy control unit, 3 is a high voltage generator, 10
Is a perspective brightness control unit, 11 is a computer, and 12 is a memory.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-55-57300 (JP, A) JP-A-59-44798 (JP, A) JP-A-54-80098 (JP, A) JP-B-58- 7039 (JP, B1) JP 57-50037 (JP, B1)

Claims (1)

[Scope of utility model registration request] 1. A fluoroscopic brightness control section for optimally controlling the fluoroscopic tube voltage based on the X-ray intensity of the object under fluoroscopy to set the brightness of the fluoroscopic image displayed on the TV monitor to a predetermined value, and a radiographic tube at the time of imaging. An X-ray controller including an imaging control unit that sets a voltage, an imaging tube current, and an imaging time, and a photo timer that detects an X-ray transmission amount of an object during imaging and shuts off X-ray exposure when the X-ray transmission amount reaches a predetermined value. In the fluoroscopic imaging apparatus, data relating to the optimum fluoroscopic tube voltage corresponding to different thicknesses of the subject, the optimum video tube voltage substantially corresponding to the subject thickness, and the time-current product of the radiography tube corresponding to the subject thickness are displayed. Each memory to store,
Based on the optimum fluoroscopic tube voltage by the fluoroscopic brightness control unit during fluoroscopy, the corresponding subject thickness is read from the memory, and the respective optimum photographing tube voltage and photographing tube current time product corresponding to this subject thickness are made the same. Means for reading out from the memory, and calculating means for decomposing a constant multiple value of the obtained tube current time product under the maximum tube current according to the X-ray tube rating into the shortest image capturing time, and calculating each. And a means for setting the photographing tube current, the photographing time and the optimum photographing tube voltage obtained by the calculation means in the photographing control section as photographing conditions, wherein the set photographing time is used as a backup time of a photo timer. X-ray fluoroscopic imaging device.