JPH05130991A - X-ray image detector for medical treatment - Google Patents

Abstract

PURPOSE:To obtain an X-ray image having good sharpness and resolution and to provide the protection against the transmitted X-rays to the rear of the device which iniure a human body by forming the front face on the X-ray incident side of a device container housing an X-ray phosphor, CCD element and glass fibers of a soft X-ray absorbing material consisting of an aluminum plate. CONSTITUTION:A ceramic substrate 5 mounted with a complete X-ray image sensor is fixed via an X-ray shielding material 13 consisting of a lead plate in the bottom on the inner side in the container 1. The front face part 11 of the container 1, i.e., the surface of the X-ray incident side including the flank parts of the container are formed of the aluminum plate which is the soft X-ray absorbing material and this Al plate is joined water-tightly with a bottom part 13 which is the rear face part of the container 1. The soft X-rays are absorbed by the soft X-ray absorbing material provided in the front face part on the X-ray incident side of the absorbing container in such a manner and, therefore, the X-ray image from a solid-state image pickup element is not disturbed by the X-rays scattered at the time of the passage of the X-rays through the teeth and the sharp X-ray image is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical X-ray image detecting apparatus, and more particularly to a small dental X-ray image detecting apparatus which is used by being inserted into the oral cavity for dental imaging.

[0002]

2. Description of the Related Art In dental treatment, X which has penetrated a tooth part
The X-ray image is converted into an optical image by a fluorescent screen in a small X-ray image detection device inserted behind an intraoral tooth, and is projected onto an image pickup surface of a solid-state image pickup device such as a CCD device by a glass fiber to obtain a digital signal. The intraoral radiography system that converts the image into the image and reproduces the dental transmission image on the monitor image is being widely used.

X-rays emitted from an X-ray source are transmitted through a tooth portion which is a subject and are converted into an optical image having a brightness proportional to the intensity of transmitted X-rays on the phosphor screen of the X-ray phosphor. , X-rays transmitted through the X-ray phosphor are not only unnecessary anymore,
Unnecessary X-rays may adversely affect the CCD element as well, so it is necessary to take measures.

In the conventional X-ray image detecting apparatus, there has been an attempt to cover the glass fiber clad with an X-ray absorbing material or mold the glass fiber itself with, for example, lead glass to give an X-ray shielding ability. There is an attempt to reduce the X-ray irradiation dose to the.

Further, in the conventional X-ray image detecting apparatus, the optical input surface or the output surface of the glass fiber for transmitting an optical image is processed so as to be oblique to the fiber strand axis, and the image pickup by the CCD element is performed. It is known to employ a method of projecting a reduced optical image on a surface. In this case CC
The image pickup surface of the D element is arranged parallel to the X-ray direction, or it is arranged at a place inside the container away from the X-ray transmission region behind the fluorescent screen to avoid the influence of the X-ray on the CCD element. Is known (Japanese Patent Laid-Open No. 2-249537).

[0006]

The above-mentioned conventional device in which the glass fiber is formed obliquely with respect to the axis to keep the CCD element away from the X-ray irradiation area is the image projected on the fluorescent screen of the subject. However, since the resolution of the reconstructed X-ray image is reduced and the device becomes larger, it is suitable for an X-ray image detection device that is inserted into the oral cavity and used for dental treatment. Is not appropriate.

Further, before reaching the fluorescent screen from the X-ray source, a part of the X-rays are scattered when passing through an object such as tooth tissue, and low-energy scattered X-rays are generated.
Since the CCD element responds to low-energy soft X-rays of several keV or less and generates an electric signal, the X-ray image on the monitor reproduced by capturing the optical image of the fluorescent screen with the CCD element is the tooth tissue. As a result of being disturbed by scattered X-rays from the etc., the sharpness of the image is reduced. Such scattered X-rays cannot be avoided even if the CCD element is arranged in the apparatus so as to avoid the X-rays that go straight from the X-ray source as described above.
It will enter the device and disturb the image signal. Further, in the conventional X-ray image detecting element, since the human body is irradiated with the X-rays passing behind the CCD element, X-ray protective measures are required.

In view of the above problems, the present invention minimizes or eliminates unnecessary scattered X-ray irradiation that adversely affects the CCD element, and obtains an X-ray image with good definition and resolution.
Moreover, it is an object of the present invention to provide a medical X-ray image detection device that protects a transmitted X-ray to the rear of the device that harms the human body.

[0009]

In the medical X-ray image detecting apparatus of the present invention, an X-ray phosphor, a solid-state image sensor, a fluorescent screen of the X-ray phosphor, and an image-pickup surface of the solid-state image sensor are optically coupled. A medical X-ray image detection apparatus comprising a glass fiber and an image-connectable glass fiber accommodated in a container, wherein at least the X-ray incident side front surface of the container is formed of a soft X-ray absorbing material. It is characterized by.

In such a medical X-ray image detection apparatus,
The glass fiber is preferably surface-attached to the phosphor screen so that the axis of the glass fiber strand is substantially perpendicular to the phosphor screen of the X-ray phosphor.
The rear surface of the container in the X-ray irradiation direction from the X-ray phosphor is X
A material including a line shielding material is adopted.

[0011]

In the container of the X-ray image detecting apparatus of the present invention, since at least the X-ray incident surface is formed of the soft X-ray absorbing material, high energy such as characteristic X-rays that have passed through the tooth part and the surrounding tissue can be obtained. Although the X-rays pass through the soft X-ray absorbing material and are projected on the fluorescent screen, the scattered X-rays scattered at the tooth portion have low energy, and are absorbed by the soft X-ray absorbing material to cause a CCD element or fluorescent light. Do not reach the face. Therefore, the CCD element does not generate an unnecessary disturbance signal due to the scattered X-rays in the image signal.

As the soft X-ray absorbing material, a metal aluminum plate is used alone or as a synthetic resin plate and a plywood, or a rare earth metal or its compound is appropriately attached to, attached to or mixed with the synthetic resin plate. Used. The thickness is generally determined experimentally in consideration of the radiant X-ray intensity and energy distribution of the X-ray source, but it is a practical intraoral radiography apparatus, and the thickness of the aluminum plate is 0.5 to
A range of 5 mm is suitable.

In the X-ray image detecting apparatus of the present invention, the one end face of the glass fiber is so arranged that the axis of the glass fiber element wire is substantially perpendicular to the phosphor screen of the X-ray phosphor. The image resolution does not decrease because it is attached to the. Further, the other end surface of the glass fiber can be attached to the image pickup surface of the solid-state image pickup device perpendicularly to the fiber axis to shorten the axial length of the glass fiber, that is, the width of the glass fiber. Can be made thin and small.

[0014]

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

1 (A) and 1 (B) show a cross-sectional view and a vertical cross-sectional view of a dental X-ray image detection apparatus according to one embodiment, the bottom (X) inside the container is shown in the container 1. X-ray shielding member 13 made of a lead plate is used to
A ceramic substrate 5 carrying a set of line image sensors is fixed. The X-ray shielding material 13 is the X
This is to prevent X-rays from being exposed to the human body by allowing the rays to penetrate to the back of the apparatus.

The front surface portion 11 of the container 1, that is, the surface on the X-ray incident side, including the side surface portion of the container, is formed of an aluminum plate, and this aluminum plate is watertightly the rear surface portion of the container 1. Is joined to the bottom portion 13. The aluminum plate of the container front portion 11 is a soft X-ray absorbing member.

The CCD substrate 4 is mounted on the ceramic substrate 5.
Of the glass fiber 3 is attached to the image pickup surface of the CCD element 4, and the thin X-ray phosphor 2 is applied to the other end of the glass fiber 3. .. Such an X-ray image sensor is
It is located behind the container front surface 11 of the radiation absorbing member, and the entire three-layer structure including the CCD element 4, the glass fiber 3 and the thin X-ray phosphor 2 is thinned.

The X-ray phosphor 2 is projected with X-rays transmitted from the X-ray source 9 through the target subject and the front part 11 of the container 1 to emit a fluorescent image, and the image is emitted from the glass fiber 3.
And is converted into an electric signal on the imaging surface of the CCD element 4. This output signal is sent to the cable 7 including the lead wire 71.
Is connected to the control device 8 outside the device.

The X-ray from the X-ray source is applied to the tooth 92, the jawbone,
Low energy scattering X generated when penetrating soft tissue
Since the line is absorbed by the container front surface portion 11 of the soft X-ray absorbing member of the aluminum plate, it hardly reaches the CCD element. The entire container 1 may be formed of a soft X-ray absorbing member such as an aluminum plate. Also this container 1
A structure in which the outer surface of the member is formed of a synthetic resin body and the inner surface of which is covered with an aluminum plate can be appropriately adopted.

FIG. 2 shows a mode of use of the dental X-ray image detection apparatus 10 of the present invention. The container 1 of the apparatus 10 is shown in FIG.
The control device 8 to which the cable 7 from
The output signal from the D element is integrated and edited, and the monitor 8
The image is reproduced on the display of No. 1 and the X-ray image is printed on the paper by the printer 82 if necessary.

Therefore, when using the present apparatus 10,
When the X-ray of the small X-ray generator 9 is applied to the tooth 92 while holding it behind the target tooth 92 in the oral cavity requiring radiography, a transmitted X-ray image of the tooth 92 is displayed on the monitor 81. Be done.

[0022]

The medical X-ray image detecting apparatus according to the present invention comprises a C
The soft X-ray absorbing material provided on the front surface of the X-ray incidence side of the container absorbs the soft X-rays that a solid-state image sensor such as a CD element is sensitive to and generates an electric signal. X from the solid-state image sensor due to X-rays scattered when passing
A clear X-ray image can be obtained without disturbing the line image.

Further, if the end face of the glass fiber for transmitting the fluorescence image of the present apparatus is a surface which is perpendicular to the axis of the glass fiber strand and is attached to the phosphor screen, the image pickup surface of the solid-state image pickup device. The projected image is not reduced and the image resolution does not decrease. Therefore, in addition to the effect of eliminating the influence of the scattered X-rays, it is effective in clarifying the X-ray image and improving the resolution. Further, if the rear surface portion of the storage container is formed to include the X-ray shielding material, X-rays transmitted to the rear of the device can be blocked and X-ray exposure during treatment can be reduced.

[Brief description of drawings]

FIG. 1 is a horizontal sectional view (A) and a vertical sectional view (B) of a dental X-ray image detection apparatus according to an embodiment of the present invention.

FIG. 2 is an X-ray imaging system diagram using a dental X-ray image detection device.

[Explanation of symbols]

 1 Container 11 Container Front Surface 12 Container Rear Surface 2 X-ray Phosphor 3 Glass Fiber 4 CCD Element 5 Substrate 7 Cable 8 Controller 81 Monitor 9 X-ray Generator 92 Tooth Part

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[Procedure amendment]

[Submission date] November 22, 1991

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Fig. 2]

[Figure 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Norio Takahashi, No. 1126, 1126 Ichinomachi, Hamamatsu City, Hamamatsu Photonics Co., Ltd. (72) Inventor Takao Makino, 680, Higashihamanamicho, Fushimi-ku, Kyoto City Morita Manufacturing Co., Ltd. (72 ) Inventor Keisuke Mori 680 Higashihaman-cho, Fushimi-ku, Kyoto City Morita Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. An X-ray phosphor, a solid-state image sensor, and the X-ray
A medical X-ray image detection apparatus comprising a container and a glass fiber that connects a fluorescent surface of a linear phosphor and an imaging surface of a solid-state image sensor so that an optical image can be formed in the container. An X-ray image detection apparatus for medical use, characterized in that the front surface on the incident side is formed to include a soft X-ray absorbing material. 2. The glass fiber is surface-bonded to the phosphor screen so that the axis of the glass fiber strand is substantially perpendicular to the phosphor screen of the X-ray phosphor.
Alternatively, the medical X-ray image detection device according to item 2. 3. The medical X-ray image detecting apparatus according to claim 1, wherein the rear surface of the container in the X-ray irradiation direction from the X-ray phosphor contains an X-ray shielding material.