JPS60127650A - X-ray detector for scattered ray protective type ct - Google Patents

Abstract

PURPOSE:To prevent scattered rays from being incident into the reference channel part by mounting an X-ray shielding plate on the front face of an X-ray incidence window on the border line between an ordinary channel part and reference channel part. CONSTITUTION:A scattered ray shielding plate 21 is mounted on the front face of an X-ray incidence window 7 and on the border line between an ordinary channel part 9 and the reference channel part 10. The shielding plate 21 is formed of a material impervious to X-rays or having large X-ray absorption. Such an X-ray shielding plate 21 is mounted on the front face of the incident window 7 for preventing the scattered rays 12 emitted from a subject to be detected from being incident to the reference channel part 10, while only the rectilinear X-rays from the X-ray source S are incident to the channel part 10. Thereby, the scattered rays can be prevented from being incident to the reference channel part.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to an XWA detector used in an X-ray tomography device, and more specifically, to an XWA detector used in an X-ray tomography device, and more specifically, to an The present invention relates to an X-ray detector configured to also detect the intensity of X-rays that have passed through.

<Prior Art> FIG. 1 is a block diagram showing an example of a conventional X1m detector of this type. In the figure, 1 is the subject, S is X1li, 3
is an X-ray detector. The X-ray detector 3 is a sealed case 4
The case has a large number of anode plates 5 and cathode plates 6 arranged substantially parallel to the direction of incident X-rays 11, and the inside of the case is filled with high-pressure gas (for example, xenon gas) 8. . Incident X-rays are transmitted through the X-ray entrance window 7 on the front of the case 4.
The gas passes through and enters the electrode compartment consisting of the anode plate 5 and cathode plate 6, and the gas 8 is separated by N. A high voltage is applied to the electrode plates (anode plate and cathode plate), and neck charges are temporarily captured by the anode. The ionized charge corresponds to the X-ray energy at that time, and it can be detected from the anode plate (the current q corresponds to this energy, so by detecting this current, the input @X m energy can be detected). It has become.

In this case, the X-ray detector detects the
An electrode compartment, a so-called normal channel section 9, for detecting X-rays, and a lephrene metre 11 disposed outside the normal channel section for detecting X-rays (original xm) that pass through the outside of the subject and enter X-ray detection in the reference channel section 10 is a detection end for controlling the intensity of the X-ray source S.

By the way, when the subject 1 is large (as shown in the figure), the scattered radiation 12 from the subject 1 enters the reference channel section 1O, causing an error in the measurement of the output intensity of the X-ray source S. There is a drawback that the influence of inter-channel interference from the normal channel unit 9 is also increased.

(Object of the Invention) The present invention has been made in view of such problems, and its purpose is to prevent scattered radiation from entering the reference channel section and to prevent interference from the normal channel section. An object of the present invention is to provide a scattered radiation-protected X-ray detector for CT.

(Structure of the Invention) The present invention that achieves the above object includes a sealed case filled with an X-ray detection gas, a plurality of planar anode plates and a plurality of planar cathodes provided within the case. These plates constitute a number of detection chambers spatially partitioned by an anode plate and a cathode plate, and the central part transmits the object and enters through the X-ray entrance window at the front end of the case. In the CT111 X-ray detector, the normal channel section is configured to detect X-rays, and a reference channel section is provided outside the normal channel section to detect straight X-rays passing outside the subject. In front of the X-ray entrance window on the boundary line between the
The X-ray shielding plate is made of a material that shields and covers the XFj source and extends in the direction of the XFj source to an extent that can prevent scattered radiation from the subject from entering the reference channel portion l\.

(Embodiment) FIG. 2 is a configuration diagram showing an embodiment of the present invention. The difference between this embodiment and the conventional example shown in FIG. and reference channel section 1
This is the point where the scattered radiation shielding plate 21 was located on the boundary line with 0. The shielding plate 21 is an X-ray shielding plate made of a material that does not transmit X-rays or has a large X-ray absorption, and has a triangular heel shape in cross section, and has a triangular shank M (the bottom of which is joined to the front surface of the entrance window 7). The height of the triangular bar is such that the scattered radiation 12 from the subject 1 does not go beyond the tip of the cone and enter the reference channel portion 1O.
The length in the direction perpendicular to the plane of the drawing is at least the same as the width of the X-ray entrance window 7 (the width in the direction perpendicular to the plane of the drawing).

By attaching such an X-ray shielding plate 21 to the front surface of the entrance window 7, scattered rays 12 from the subject 1 can be blocked as shown in the figure.
Lef Aren Methi 1? The great sword to the flannel part 1O was prevented,
The reference channel section 1O has a straight line of X from the X-ray source S.
If only the line is incident, it will be loud. I, where the width of the base of the shielding plate 21 is significantly wider than the electrode spacing, =
The normal channel part 9 and the reference channel A/flannel part 10
and J3' (completely separated, and there is no mutual interference) in the movement region of the electric charges.

Note that the shape of the shielding plate is not limited to a triangular pyramid cross section, but may also be a trapezoid as shown in Figure 3 (a), a shape with curved sides as shown in Figure 3 (b), etc. It may be.

(Effects of the Invention) As explained above, the present invention has a structure in which an X-ray shielding plate is attached to the front surface of the X-ray entrance window on the boundary line between the normal channel section and the reference channel section. Therefore, it is possible to prevent a large amount of scattered radiation from the subject to the reference channel, and also to prevent mutual interference with the normal X-ray source. It can be detected at the

Note that the same effect can be obtained even if the reference channel section is provided only on one side.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a conventional X-ray detector, Fig. 2 is a block diagram showing an embodiment of the X-ray detector according to the present invention, and Fig. 3 is a block diagram showing another embodiment of the shielding plate. FIG. S... X-ray source 1... Subject 4... Woos 5... Anode plate 6... Cathode plate 7... X-ray entrance window 9... Normal channel part 1O... Reference Channel part 11... X-ray 12... Scattered radiation 21... X-ray shielding plate 1 diagram

Claims (1)

[Claims] It includes a sealed case filled with X-ray detection gas, a plurality of flat anode plates and a plurality of flat cathode plates installed in the case, and the anode plate and the cathode plate It constitutes a large number of spatially partitioned detection compartments, and the central part is a normal channel part that detects the X-rays that have passed through the subject and entered the X-ray entrance window at the front end of the case. A reference channel part is provided on the outside of the C to detect straight X-rays passing outside the subject.
In the T-use X-ray detector, a material is provided in front of the X-ray entrance window on the boundary line between the normal channel section and the reference channel section, and is made of a material that blocks X-rays, and prevents scattered rays from the subject from entering the reference channel section. X to the extent that it can prevent
A CTl41 X-ray detector with scattered radiation protection, characterized by having an X-ray shielding plate extending in the direction of the radiation source.