JPS62216199A - X-ray ct device - Google Patents

Abstract

PURPOSE:To minimize an amount of X-ray radiation on a patient by installing a scanning device capable of changing an amount of X-ray radiated on an inspection target in response to any change in concentration of image forming agent on a screen image. CONSTITUTION:A scan control device 10 is operated to start photographing at low concentration to the extent at which any change in concentration of image forming agent may be merely recognized, and a concentration change in the image forming agent of the picture image of an indication device 6 is observed under this condition. When the concentration of the image forming agent increases gradually and reaches a time point (a), the device 10 is operated to increase the amount of X-ray to continue scanning, and thereafter when the concentration of the image forming agent decreases gradually and reaches a time point (b), amount of X-ray is decreased by operating the device 10. In addition, any condition change can be applied to a mounting control device 7 by means of the device 10, and an amount of image forming agent to be injected by an injector 11 can be regulated as necessary. Owing to such constitution, photographing can be carried out under the optimum condition and an amount of X-ray radiation on a patient can be reduced as small as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an X-ray CT apparatus, and particularly to its dynamic Skillen system.

Technical background of the invention and its problems] Generally, when performing dynamic scanning with an X-ray CT device, a contrast agent is injected into the subject and X-rays are irradiated ().
The images are displayed in real time to obtain moving images.

By the way, when we calculate the time density curve that represents the change in the concentration of the contrast agent injected into the subject on the image, we find that the contrast agent concentration is low between A and 8 and between a and b, as shown in Figure 2.
It becomes high between then and becomes low again between b and c. In fact, the image that can contribute to diagnosis is the image between a and b, which is the section where the contrast agent concentration is high.

However, in such a time density curve, the times between A-8, a-b, and b-c vary and are not constant due to individual differences among patients. A high dose of X-rays was irradiated over a period of 0 to 30 minutes to obtain images under the same conditions.

However, in this way, a high dose of X
A-
Also during the 8th period and b-c period, the patient was exposed to a high dose of X-rays, which caused the problem that the patient's exposure dose increased more than necessary.

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an X-ray C processing device that can reduce the radiation dose to a patient as much as possible.

[Summary of the Invention] The outline of the present invention for quickly achieving the above object is to provide an X-ray that can dynamically scan an object injected with a contrast agent by applying X-rays to the subject and display the image in real time. The CT apparatus is provided with a scan control device that can change the amount of X-rays irradiated to the subject in real time according to changes in the contrast agent concentration on the image.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described with reference to FIG.

Reference numeral 1 denotes an X-ray tube that irradiates the subject with Pkm X-rays into which a contrast medium has been injected by an injector 11, and 2 a detector that detects projection information thereof. The X-ray tube 1 is driven by an X-ray generator 4, and the X-ray generator 4 is controlled by a CPU 9 and an X-ray controller 8.

3 is an A/D converter that converts the analog signal obtained by the detector 2 into a digital signal, and 5 is this A/D converter.
This is a high-speed reconstruction device that reconstructs an image based on the digital signal from the /D converter 3.

The high-speed reconstruction device 5 is controlled by the CPU 9, and the images reconstructed by the high-speed reconstruction device @5 are displayed on the display device 6 in real time. In addition, 7 is a gantry control device, and 12
is an image storage device.

] 0 is a scan control device, which can change the dose of X-rays emitted from the X-ray tube 1 in real time through the CPU 9.
The conditions of the gantry control device 7 can be changed in real time through the PU 9. Furthermore, the injector 11 can also control the amount of contrast medium to be injected into the subject.

Therefore, the above-described apparatus can perform copying under the most appropriate conditions by operating the scan control device 10 while using the display device 6 that displays the image of the subject P in real time. More specifically, by operating the scan control device 10, for example, first, a shadow starts to be formed by irradiating X-rays at a low dose that allows the change in contrast agent concentration to be seen, and in that state, an image is displayed on the display device 6. Observe changes in the contrast agent concentration above. Then, when the contrast agent concentration gradually increases and reaches the point 9 in FIG. When the temperature drops to point b in Figure 2, operate the scan control device 10 again to
Reduce dose. Also, if necessary, the conditions of the gantry control device 7 may be changed by the scan control device 10,
The amount of contrast medium injected by the injector 11 can be adjusted.

In this way, according to this apparatus, prefectural imaging can be performed under the most appropriate conditions, and the radiation exposure line d of the patient can be minimized.

Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to the above embodiment, and can be modified as appropriate within the scope of the gist of the present invention.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to perform X-ray exposure at a dose that corresponds to the change in contrast agent concentration using the scan control device while viewing the image, which improves clinical results. The patient's exposure dose can be reduced as much as possible without sacrificing radiation exposure.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the X-ray CT apparatus of the present invention.
FIG. 2 is a drawing showing a time density curve. 10... Scan control device, P... Subject. Agent Patent Attorney Yudo Noriyuki Chika
Ogo Norifu’s condolence illustration 2

Claims (1)

[Claims] In an X-ray CT device that can perform dynamic scanning by irradiating X-rays onto a subject into which a contrast agent has been injected, and display the resulting image in real time, An X-ray CT apparatus characterized by being equipped with a scan control device that can change the amount of X-rays to be exposed to in real time.