JP2002214729A - Radiographic image photographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good image with low noise even when each member is closely-packed and reciprocal spaces come close. SOLUTION: A metallic casing 21 is partitioned into two divisions 23 and 24 with a partition 22, a base 25 is fixed in the partition 23, and an X-ray image detection panel 26 is provided on the base 25. A supply circuit part 30 for supplying electric power to a circuit part in the division 23 is built in the division 24. The casing 21 has the partition 22 in the same way, and is covered with a metallic lid 33 which has X-ray permeability at least on the division 23. The supply circuit part 30 and the circuit part of other sections are isolated by the partitions 22 and 32 provided in the casing 21 and the lid 33. Thereby, an electromagnetic shielding effect can be given, and the circuit part in the division 23 picks up electromagnetic noise generated from the supply circuit part 30 to prevent the lowering of S/N performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable radiographic digital image photographing apparatus.

[0002]

2. Description of the Related Art Conventionally, an apparatus for irradiating an object with radiation and detecting an intensity distribution of the radiation transmitted through the object to obtain a radiation image of the object has been used in industrial nondestructive inspection and medical diagnosis. Widely used in general. A common method of such imaging is a film / screen method for X-rays. This is a method of capturing an image by combining a photosensitive film and a phosphor having sensitivity to X-rays. A sheet of a rare earth phosphor that emits light when irradiated with X-rays is held in close contact with both surfaces of the photosensitive film, and the X-rays transmitted through the subject are converted into visible light by the phosphor,
The light can be visualized by capturing the light with a photosensitive film and developing the latent image formed on the film by a chemical treatment.

[0003] On the other hand, with the progress of digital technology in recent years,
There is a demand for a method of converting a radiation image into an electric signal, processing the electric signal, and then reproducing the electric signal as a visible image on a CRT or the like to obtain a high-quality radiation image. As a method of converting such a radiation image into an electric signal, for example, Japanese Patent Application Laid-Open Nos.
As in JP-A-11395, etc., a transmitted image of radiation is temporarily stored in a phosphor as a latent image, and the latent image is photoelectrically read out by irradiating an excitation light such as a laser beam later to obtain a visible image. There has been proposed a radiation image recording / reproducing system which outputs the image data as an image.

[0004] Further, with the progress of semiconductor process technology in recent years, an apparatus for similarly taking a radiographic image using a semiconductor sensor has been developed. These systems have an extremely wide dynamic range compared to conventional radiographic systems using photosensitive films, and offer the practical advantage of being able to obtain radiation images that are not affected by fluctuations in radiation exposure. Have. At the same time, unlike the conventional photosensitive film method, there is an advantage that chemical processing is not required and an output image can be obtained immediately.

FIG. 2 is a conceptual diagram of a system using such a radiographic image capturing apparatus. X-rays emitted from the X-ray generator 1 are irradiated on the subject S, and X-ray images detected by photoelectric conversion elements in which the X-rays transmitted through the subject S are arranged in a two-dimensional lattice in the X-ray imaging apparatus 2 are detected. Detected by the sensor 3. The image signal output from the detection sensor 3 is subjected to digital image processing by the image processing means 4, and an X-ray image of the subject S is displayed on the monitor 5.

Conventionally, this type of imaging apparatus is installed and used in a radiation room. However, in recent years, a thin and lightweight portable X-ray imaging apparatus called an electronic cassette has been used in order to enable imaging of a wide range of parts more quickly.

FIG. 3 is a sectional view of a conventional electronic cassette viewed from the side. An electronic cassette used for such X-ray photography or the like includes a phosphor 11a for converting X-rays into visible light, a photoelectric conversion element 11b arranged in a grid for converting the visible light into an electric signal, and a photoelectric conversion element 11b. A substrate 11c having an element 11b formed on a surface thereof, and a base 1 supporting the substrate 11c.
2, a circuit board 13 on which electronic components for processing the photoelectrically converted electric signals are mounted, and wiring 14, a housing 15 for housing them, and a power supply circuit 16 for supplying power to the photoelectric conversion element 11b and the circuit board 13. And a power supply wiring 17 and the like.

A specific configuration of the power supply circuit 16 includes a configuration including a battery and a DC / DC power supply circuit, or a configuration in which a predetermined voltage is externally supplied by a power supply cable (not shown) from the outside.
/ DC power supply to generate various voltages.

It is desired that such an electronic cassette be small and light in consideration of portability. For miniaturization, it is necessary to reduce the size of each electronic circuit unit itself and to increase the mounting density of each electronic circuit.

[0010]

However, in the above-mentioned conventional example, since the photoelectric conversion element 11b handles very low level signals, it is extremely susceptible to electromagnetic noise. When this electromagnetic noise is received, image noise is superimposed on the captured image, and the image quality is reduced, which adversely affects medical diagnosis. As a factor for generating the electromagnetic noise, switching noise generated from a power supply circuit 16 such as a DC / DC power supply contained in the housing 15 is large, and then easily generated from an electric circuit, particularly a digital circuit.

As a method of preventing such electromagnetic noise, there is a method of surrounding the source with a shield case or shielding the affected side. However, any of these methods conflicts with the reduction in size and weight of the electronic cassette itself and the reduction in cost. Will be.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a radiographic image capturing apparatus capable of obtaining high-quality images with low noise.

[0013]

According to the present invention, there is provided a radiation image capturing apparatus for irradiating a subject with radiation emitted from radiation generating means and detecting a radiation distribution transmitted through the subject. In an imaging device, a radiation detecting unit in which photoelectric conversion elements for detecting radiation transmitted through a subject are arranged in a two-dimensional array, an electric circuit board for processing an electric signal from the detecting unit, the electric circuit board and the detection A power supply unit for supplying power to the means, and a housing containing the detection unit, the circuit board and the power supply unit, and a partition for blocking electromagnetic noise was formed between the members in the housing. It is characterized by the following.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiment. FIG. 1 is a sectional view of the first embodiment viewed from the side. The metal casing 21 is divided into two compartments 23 and 24 by a partition 22 inside the compartment.
Inside, a metal base 25 is fixed at an interval from the bottom of the housing 21, and an X-ray image detection panel 26 is provided on the base 25. The X-ray image detection panel 26 is a fluorescent screen 26
a, the photoelectric conversion element 26b, and the substrate 26c are laminated. A glass plate is often used for the substrate 26c because of the necessity of having no chemical action with the semiconductor element, withstanding the temperature of the semiconductor process, and dimensional stability. On such a substrate 26c, the photoelectric conversion elements 26b are formed in a two-dimensional array by a semiconductor process. The fluorescent plate 26a is formed by applying a phosphor of a metal compound to a resin plate, and is integrated with the substrate 26c by adhesion.

An electronic component 28 for processing a photoelectrically converted electric signal is provided on the back side of the base 25 via a protrusion 27.
A circuit board 28 on which a is mounted is disposed, and is connected to the photoelectric conversion element 26b by a flexible circuit board 29.

On the other hand, the photoelectric conversion element 26
b, power supply circuit section 3 for supplying electric power to circuit board 28
0 is built in, and a part of the central partition 22 is provided with a through hole from the power supply circuit unit 30 via a wiring 31 and connected thereto. Then, the housing 21 is a partition 3 for combining the partition 22.
2 and at least on the section 23 is sealed by a metal lid 33 having X-ray transparency.

In this embodiment, the power supply circuit 30
And the other electric members described above, the casing 21, the lid 3
3 are separated by partitions 22 and 32 provided respectively, so that an electromagnetic shielding effect can be provided between the sections 23 and 24. Electromagnetic noise generated from the electric circuit of the power supply system is picked up by the flexible circuit board 29 and the like, and S / S N performance can be prevented from being impaired. Further, there is an effect that the influence from external noise can be reduced.

The material of the housing 21 and the lid 33 is not only made of metal, but also made of iron having a high electromagnetic shielding effect.
It is also effective to use a material such as a magnesium alloy, a magnetic material, or another alloy. Furthermore, it is also possible for only the partitions 22, 32 to be of such a material.

In this embodiment, the housing 21 and the cover 3 are provided without specially providing a shield case for noise suppression.
Since the shield itself is a shield case, the cost can be reduced, and an electronic cassette that is small, lightweight, low-noise, and has good image quality can be realized.

In the present embodiment, an example is shown in which the partitions 22, 32 are provided between the power supply circuit section 30 and the other electric circuit sections. However, the present invention is not limited to this. By integrating the base 25 and the housing 21, even in the section 23, for example, by providing a partition between the X-ray image detection panel 26 and the electric circuit unit by the housing 21, interference between them is further reduced. It can also be reduced.

[0021]

As described above, in the radiographic imaging apparatus according to the present invention, even when the members are mounted at a high density and the distance between the members is close to each other, the power supply section is used to partition the housing. Therefore, leakage of electromagnetic noise generated from the power supply unit is reduced, and a low-noise image can be obtained. In addition, since the partition is integrated with the housing, there is no need to provide a noise suppression member such as a shield case in the power supply unit, and the size can be further reduced, and the cost can be reduced because the shield material can be further reduced. .

[Brief description of the drawings]

FIG. 1 is a side sectional view of an embodiment.

FIG. 2 is a conceptual diagram of a system.

FIG. 3 is a cross-sectional view of a conventional example viewed from the side.

[Explanation of symbols]

 Reference Signs List 21 housing 22, 32 partition 23, 24 section 25 base 26 X-ray image detection panel 28 circuit board 29 flexible circuit board 30 power supply circuit section 33 lid

Claims (5)

[Claims] 1. A radiation image capturing apparatus for irradiating a subject with radiation emitted from a radiation generating means and detecting a radiation distribution transmitted through the subject, a photoelectric conversion element for detecting the radiation transmitted through the subject in a two-dimensional array. The radiation detecting means disposed, an electric circuit board for processing an electric signal from the detecting means, a power supply unit for supplying power to the electric circuit board and the detecting means, the detecting means, the circuit board and the A radiation image capturing apparatus, comprising: a housing having a power supply unit therein, wherein a partition for blocking electromagnetic noise is formed between the members in the housing. 2. The radiation image capturing apparatus according to claim 1, wherein the partition is provided at least between the power supply unit and the other members. 3. The radiation image capturing apparatus according to claim 1, wherein the partition is provided at least between the photoelectric conversion element and the other members. 4. The housing according to claim 1, wherein the housing is made of a material having an electromagnetic shielding effect, such as iron, magnesium alloy, permalloy, a magnetic material, or another alloy.
A radiographic image capturing apparatus according to claim 1. 5. The radiation image capturing apparatus according to claim 1, wherein the power supply unit is a switching power supply such as a DC / DC power supply.