JPH03295541A - X-ray diagnostic device - Google Patents

Abstract

PURPOSE:To equalize the exposure dose which a body to be examined receives by providing a counting means for counting a dose collected by a detector in a prescribed period, and an exposure dose control means for controlling an X-ray exposure dose at the time of counting this time so that the dose counted in the previous time becomes a prescribed set value. CONSTITUTION:X ray emitted from an X-ray tubular ball 5 transmits through a body 3 to be examined and is detected by a detector 7. Subsequently, the detected X-ray dose is converted to the charge quantity, and in a count detector 13, the dose is counted at every prescribed sampling period, and also, an operator sets the X-ray dose collected to the detector 7 during one sampling period to a dose setting part 8 in advance, therefore, a comparing part 9 compares this set value and a count value from the count detector 13 and derives difference data of both of them. Next, a tube current controller 11 controls the X-ray dose emitted from the X-ray tubular ball 5 in the present sampling period so that the difference data derived at the time of the previous sampling period becomes zero.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention provides an X-ray method in which a subject is placed on a bed and X-rays are irradiated to the subject to take a scanogram image. The present invention relates to radiation diagnostic equipment.

(Prior art) In general, an X-ray diagnostic apparatus irradiates a bed with a subject on it while moving in a fixed direction, detects projection data transmitted through the subject, and generates a scanogram image. ing. Conventionally, in such an X-ray diagnostic apparatus, the exposure dose and the moving speed of the bed are fixed. Therefore, a constant amount of X-rays are always irradiated to the subject regardless of the size of the imaging area.

For this reason, as shown in FIG. 4, for example, the dose is excessive at the neck 1 where the imaging area is narrow, and the dose is insufficient at the shoulder area 2 where the imaging area is wide. Problem) As described above, in the conventional X-ray diagnostic apparatus, there are areas where the dose is excessive and areas where the dose is insufficient.

For this reason, areas with excessive doses receive more radiation than necessary, which has an adverse effect on the human body. On the other hand, there was a drawback that scanogram images of good quality could not be obtained in areas where the dose was insufficient.

The present invention has been made to solve these conventional problems, and its purpose is to provide an X-ray diagnostic apparatus that can uniformize the radiation dose that a subject receives.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention irradiates X-rays from an X-ray tube while moving a bed on which a subject is placed. An X-ray diagnostic apparatus that generates a scanogram image by detecting projection data transmitted through a specimen with a detector, comprising a counting means for counting the dose collected by the detector at a predetermined period, and a previous count by the counting means. It is characterized by comprising an exposure dose control means for controlling the XS* exposure dose at the time of current counting so that the dose obtained becomes a predetermined set value.

(Function) With the configuration as described above, the dose detected by the X-ray detector is counted at a predetermined period by the counting means. and,
The current X-ray exposure dose is controlled so that the count value during the previous sampling becomes a predetermined set value.

Therefore, each part of the subject is uniformly irradiated with X-rays.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of an X-ray diagnostic apparatus to which the present invention is applied. , a wedge 6 as a filter that adjusts the amount of X-rays to be irradiated, and a detector 7 that is arranged opposite to the X-ray tube and detects the amount of X-rays that have passed through the subject 3 and converts it into an amount of electric charge. and a runt detector 13 that counts the dose detected by the detector 7 at every predetermined sampling period.

Further, this X-ray diagnostic apparatus includes a computer system 10, a tube current control device 11, and an X-ray power supply device 12. 8, and a comparison section 9 that compares the set dose and the dose for one cycle obtained by the count detector 13 and outputs difference data. The tube current control device 11 outputs an operation signal to the X-ray power supply device 12 based on this difference data to control the dose emitted from the X-ray tube 5.

Next, the operation of this embodiment will be explained.

When the subject 3 is placed on the bed 4 and scanning of a scanogram image starts, the X-ray tube 5 is
A voltage is applied to the object 3 from the X-ray tube 5.
X-rays are emitted towards.

The dose of the emitted X-rays is adjusted by the wedge 6, and then transmitted through the subject 3 and detected by the detector 7. Then, the detected X-ray dose is converted into a charge amount, taken into the count detector 13, and then output to a post-processing step (not shown).

At this time, the count detector 13 counts the dose at every predetermined sampling period, and outputs this count value to the comparator 9 of the computer system 10. In addition, since the operator has previously set the X-ray dose collected by the detector 7 during one sampling period in the dose setting section 8, the comparing section 9
Then, this set value and the count value from the count detector 13 are compared to obtain difference data between the two.

Then, the tube current control device 11 controls the X-ray dose emitted from the X-ray tube 5 in the current sampling period so that the difference data obtained in the previous sampling period becomes zero. .

In this way, in this embodiment, the X-ray exposure amount during the current sampling is controlled based on the dose during the previous sampling, so that only the amount of X-rays corresponding to the imaging area of the subject 3 is irradiated. Become so.

Therefore, when the imaging area is narrow, the amount of X-rays irradiated is small, and on the contrary, when the imaging area is large, the amount of X-rays irradiated is large.

As a result, each part of the subject 3 is uniformly exposed to X-rays, making it possible to take a clear scanogram image, and solving the problem of only specific parts being exposed to large amounts of radiation. .

FIG. 2 is a block diagram showing a second embodiment of the present invention. As shown in the figure, the second embodiment is different from the first embodiment.
The difference is that the difference data output from the comparator 9 is supplied to the bed speed control device 14.

The bed speed control device 14 controls the moving speed of the bed 4 in the current sampling period so that the difference data obtained in the previous sampling period becomes zero, and controls the movement speed of the bed 4 in the current sampling period. ) is outputting operation commands.

Even in this configuration, X-rays are uniformly irradiated to each part of the subject 3, and the same effects as in the first embodiment can be obtained.

FIG. 3 is a block diagram showing a third embodiment of the present invention. In the third embodiment shown in the figure, a wedge control device 15 is provided, and the wedge control device 15 is configured to control the wedge 6 in the current sampling period so that the difference data in the previous sampling period outputted from the comparator 9 becomes zero. Position is controlled. Thereby, the X-ray dose is adjusted so that when the imaging area of the subject 3 is narrow, the dose of X-rays is small, and when it is large, the dose is increased.

Even in such a configuration, the same effects as in the first embodiment and the second embodiment can be obtained.

[Effects of the Invention] As explained above, according to the present invention, each part of the subject can be uniformly exposed to X-rays.

Therefore, it is possible to take a clear scanogram image, and the problem that only a specific part is exposed to a large amount of radiation during imaging can be solved.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the first embodiment of the present invention, Fig. 2 is a block diagram showing the second embodiment, Fig. 3 is a block diagram showing the third embodiment, and Fig. 4 is the conventional radiation dose. FIG. 3... Subject 4... Bed 5... X-ray tube 6... Wedge 7... Detector 8... Dose setting section 9... Comparison section
11... Tube current control device 13... Count detector 14... Bed speed control device 15... Wedge control device

Claims (4)

[Claims] (1) X-ray diagnostic equipment that emits X-rays from an X-ray tube while moving a bed on which a subject is placed, and generates a scanogram image by detecting projection data transmitted through the subject with a detector. a counting means for counting the dose collected by the detector at a predetermined cycle; and controlling the X-ray exposure dose during the current counting so that the dose counted last time by the counting means becomes a predetermined set value. X characterized by having an exposure dose control means for
Line diagnostic equipment. (2) The X-ray diagnostic apparatus according to claim 1, wherein the exposure dose control means controls the X-ray exposure dose by adjusting the tube current of the X-ray tube. (3) The X-ray diagnostic apparatus according to claim 1, wherein the exposure dose control means controls the X-ray exposure dose by adjusting the moving speed of the bed. (4) The X-ray diagnostic apparatus according to claim 1, wherein the exposure radiation control means controls the X-ray exposure dose by adjusting a filter provided in the X-ray tube.