JPH03224545A - X-ray tomography device - Google Patents

Abstract

PURPOSE:To eliminate the setting errors at the time of manual setting and to make improvement in photographing efficiency by automatically measuring the thickness of a subject and automatically setting the photographing conditions optimum according thereto. CONSTITUTION:An ultrasonic range finder 5 mounted on the side face of a movable aperture device 2 radiates an ultrasonic beam downward, receives the reflected wave returned by reflecting on the surface of a patient 6 and measures the distance to the surface of the patient 6 by the time until the wave returns. A control device, into which the distance from the mounting position of the ultrasonic range finder 5 to a top plate 3 of a bed is previously inputted, determines the thickness of the patient 6 by subtracting and computing the distance measured from this distance when the measured distance is sent to the control device 8. The optimum photographing conditions are, therefore, determined in accordance with this memory and are applied to an X-ray tube device 1, by which the X-ray tomographing is executed. The X-ray tomographing under the optimum conditions meeting the actual photographing section and the thickness of the subject is executed in this way.

Description

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

The present invention relates to an X-ray imaging apparatus, and more particularly to an improvement in an X-ray tomography apparatus that performs tomography of a predetermined cross section of an object by moving an X-ray tube device and a film in conjunction with each other.

[Conventional technology]

Conventionally, when performing X-ray tomography, in general, in order to determine the imaging conditions, such as X-ray tube voltage and X-ray tube current,
The thickness of the subject (patient) is measured using calipers or an ultrasonic distance meter. Optimum imaging conditions are determined empirically from the measured thickness and the imaging site, such as the head, chest, abdomen, etc. Additionally, in devices that are equipped with an image intensifier and a TV camera and can perform X-ray fluoroscopy using a TV monitor, the imaging conditions for tomography are automatically determined from the X-ray exposure conditions during fluoroscopy. Some have done this.

[Problem to be solved by the invention]

However, it is very time-consuming to measure the patient's thickness using a separate thickness measuring device, and in addition, determining the optimal imaging conditions from the measured thickness requires considerable experience and knowledge. be. In addition, it is very expensive to equip an X-ray TV fluoroscopy system that includes an image intensifier and a TV camera, and furthermore, X-ray exposure for fluoroscopy must be performed before tomographic imaging, which takes time and saves the patient. There is a problem with X-ray exposure. The present invention provides an improved X-ray tomography apparatus that is inexpensive, requires no effort, and is improved so that imaging conditions for tomography can be automatically set without causing the problem of X-ray exposure. The purpose is to

[Means to solve the problem]

In order to achieve the above object, the present invention provides an X-ray tomography apparatus that moves an X-ray tube apparatus and a film in conjunction to perform tomography of a predetermined cross section of a subject. a distance measuring means for measuring the distance to the surface of the object, and a control means for determining the object thickness from the measured distance and automatically determining the imaging conditions from the object thickness and the set imaging area. It is characterized by having the following. (Function) The distance measuring means measures the distance from it to the object surface. This distance measuring means is installed near the X-ray tube device, and its mounting position is known in advance. The thickness of the subject can be determined from the measured distance of These optimal imaging conditions are automatically set in the X-ray tube device, and X-ray tomography can be performed under the optimal imaging conditions according to the actual area to be imaged and the thickness of the subject. (Example) Next, An embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a front view of the embodiment, Fig. 2 is a side view, and Fig. 3 is a schematic diagram of the whole including a control system. As shown in these figures, an X-ray tube device 1 and an X-ray movable aperture device 2 are held by a frame 4 so as to be movable parallel to the floor surface. A bed top plate 3 is movably held on which a patient (see Fig. 3) is placed.A film is stored under the bed top plate 3, and the X-ray tube device 1 and the X-ray movable diaphragm device are The X-ray tube device 1, the movable diaphragm device 2, and the drive mechanism 7 for moving the film are built into the frame 4.The bed top plate 3 is moved when positioning the object, and is fixed when positioning is completed.An ultrasonic distance meter 5 is attached near the X-ray tube device 1, in this embodiment, on the side of the movable aperture device 2. This ultrasonic distance meter 5 emits an ultrasonic beam downward, receives the reflected wave that is reflected from the surface of the patient 6, and calculates the distance to the surface of the patient 6 based on the time it takes for the wave to return. This measured distance is sent to the control device 8.Control device W8
, the distance from the installation position of the ultrasonic distance meter 5 to the bed top 3 is input and stored in advance, and the distance measured above is subtracted from the distance to the bed top 3. The thickness of the patient 6 is determined by . This thickness measurement is to measure the thickness near the area where the tomographic image is to be taken, so move the bed top 3 and place the patient 6.
Perform this after positioning. However, since the ultrasonic distance meter 5 is attached to the side of the movable diaphragm device 2, the thickness of the patient 6 at the center of the X-ray beam cannot be measured. In such a case, after the above positioning is completed, it is desirable to shift the bed top plate 3 by the amount of the positional shift and determine the thickness at the center of the X-ray beam. The control device 8 has a region selection button 9 for setting each imaging region such as the head, chest, abdomen, etc., and a trajectory selection button 10 for selecting an imaging trajectory such as a straight line, circle, or spiral. By pressing these, you can set the region to be imaged and the trajectory to be imaged. Further, the control device 8 includes an arithmetic circuit that performs calculations such as the thickness calculation described above, and a storage circuit that stores the distance from the ultrasonic distance meter 5 to the bed top 3 and the like. This memory circuit contains information about each imaging area and
The optimal imaging conditions (X-ray tube voltage, current, etc.) determined in advance in accordance with the trajectory and the thickness of patient 6 are stored, and the imaging region and trajectory are input as described above, and patient 6 is
Immediately after the thickness of the X-ray tube 1 is automatically determined, optimal imaging conditions are determined based on the memory, and these are provided to the X-ray tube device 1. Therefore, the operator can automatically set the optimal imaging conditions by simply positioning the patient 6 and setting the imaging region and trajectory, and then simply pressing the X-ray shooting button will perform control according to the conditions. X-ray radiation is performed from the X-ray tube device 1, and the drive mechanism 7 automatically moves the X-ray tube device 1, the X-ray movable aperture device 2, and the film on the set trajectory, and the X-ray Linear tomography is performed. In this example, the ultrasonic distance meter 5 was used to determine the thickness of the patient 6, but other mechanical distance meters, such as a search rod that comes down and comes into contact with the surface of the patient 6, can be used to measure the distance. It is also possible to use a distance meter or the like to measure the distance. When using the ultrasonic distance meter 5, there is an advantage that distance measurement can be performed in a very short time, and that tomography can be started immediately if the imaging site and trajectory have been set. In addition, the thickness of the patient 6 is measured not only in a stationary state in a direction perpendicular to the bed top 3 as in the above embodiment, but also by placing the Alternatively, while moving the X-ray diaphragm 2, it can be performed at each point on its trajectory. When the X-ray tube device l moves on an orbit, the thickness of the X-ray beam naturally changes because the X-ray beam becomes oblique. The X-ray tube device 1 that is moving during actual tomography is memorized and based on this change in thickness.
It is also possible to change the shooting conditions moment by moment.

【Effect of the invention】

According to the X-ray tomography apparatus of the present invention, it is possible to automatically measure the thickness of the subject and automatically set the optimal imaging conditions accordingly, eliminating setting errors during manual settings.
Situations such as reshooting can be avoided, improving shooting efficiency. Moreover, it can save a lot of time and effort, and even people with little experience can operate it. Furthermore, the patient's exposure to X-rays can be reduced. However, the economic cost to realize these is not that high.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a side view of the same embodiment, and FIG. 3 is a schematic diagram of the entire embodiment including a control system. 1... X-ray tube device, 2... X-ray movable aperture device, 3.
... Bed top plate, 4... Frame, 5... Ultrasonic distance meter, 6... Patient, 7... Drive mechanism, 8... Control device, 9... Imaging site selection button, 10... Shooting trajectory selection button.

Claims (1)

[Claims] (1) In an X-ray tomography device that moves an X-ray tube device and film in conjunction to take a tomographic image of a predetermined cross section of the object, the distance to the surface of the object provided near the X-ray tube device. an X-ray device comprising a distance measuring means for measuring the distance, and a control means for determining the object thickness from the measured distance and automatically determining the imaging conditions from the object thickness and the set imaging region. Tomography device.