JP2009192425A - Radiation image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation image forming device capable of forming a radiation image of living small animals for an experiment with low exposure dose. <P>SOLUTION: A distortional window 24 deforms to curve inside from a pressing window 32 of a sample containing member 30 by pressure from inside of a gas filling space 14 and also the pressing window 32 pressed by the distortional window 24 deforms to curve inside of a containing space 30R to push and widen an observing site of a sample T as shown. This makes the thickness of the observing site of the sample T thinner than before the push and widening. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radiographic image generation apparatus, and more particularly to a radiographic image generation apparatus capable of obtaining a radiographic image of a bone form or tissue by irradiating a small experimental animal with radiation.

  Without administering drugs to experimental small animals artificially afflicted with arteriosclerosis, osteoporosis, etc., without slaughtering the experimental small animals, the experimental small animals are irradiated with radiation, and by the radiation that has passed through the experimental small animals, An apparatus for generating, observing, and analyzing a radiation image has been proposed (Patent Document 1). In the apparatus described in Patent Document 1, a photostimulable phosphor having high sensitivity is used as a radiation detection material in order to obtain a clear image using radiation.

In this way, it is possible to obtain a clearer image than before by using a high-sensitivity sheet for image formation, but it is possible to obtain a high-resolution image while further reducing the exposure dose of small experimental animals. Is required.
Japanese Patent Laid-Open No. 10-268450

  The present invention has been made in consideration of the above-described facts, and an object of the present invention is to provide a radiation image generating apparatus capable of generating a radiation image of a living small experimental animal with a low exposure dose.

  In order to solve the above-described problem, a radiological image generation apparatus according to claim 1 includes a shielding box in which a gas-filled space blocked from the outside is configured, a high-pressure unit that makes the gas-filled space high in pressure, A radiation source that emits radiation from one side of the shielding box to the other side; and a holding space that communicates with the outside and is disposed in a path of radiation emitted from the radiation source to transmit the radiation; and A holding portion formed with a deformation window that can be deformed so as to bend toward the inside of the holding space by making the inside of the gas-filled space high pressure with the high-pressure means in a direction in which the gas is transmitted; And an image generating unit disposed on a side opposite to the radiation source and provided with a radiation receiver for receiving the radiation transmitted through the sample.

  According to the first aspect of the present invention, when the gas filling space becomes high pressure by the high pressure means, the deformation window of the holding portion is deformed so as to curve toward the inside of the holding space. And the sample accommodated in the sample accommodation member arrange | positioned in holding | maintenance space is pushed and deform | transformed by deformation | transformation of this deformation | transformation window. As a result, the thickness of the sample is expanded and thinner than before the deformation, and the amount of radiation transmitted through the sample is increased. Therefore, the radiation dose received by the radiation receiver increases, and a clearer image can be generated with a small radiation dose.

  In the first aspect of the invention, since the holding space communicates with the outside, the outside air can be easily supplied to the sample.

The radiological image generation apparatus according to claim 2 is configured such that an accommodation space in which a sample is accommodated is configured and can be arranged in the holding space, and at a position corresponding to the deformation window when arranged in the holding space. And a sample accommodating member configured with a pressing window capable of expanding and deforming the sample accommodated in the accommodation space by pressing due to the deformation of the deformation window.
By providing the sample storage member, the sample can be appropriately arranged on the holding unit.

  The radiological image generation apparatus according to claim 3 is configured to include a seal member that is deformable so that the pressing window is curved toward the inside of the accommodation space by deformation of the deformation window. Features.

  Thus, by configuring the pressing window of the sample storage member using the deformable seal member, the sample can be expanded and deformed by the deformation of the deformation window.

  The radiological image generation apparatus according to claim 4 is characterized in that the pressing window is an opening. In this way, by simply using the pressing window as an opening, the sample can be spread and deformed by deformation of the deformation window with a simple configuration.

  The radiographic image generation apparatus according to claim 5 is characterized in that the gas-filled space is filled with a gas having a lower radiation absorption rate than air.

  Thus, the amount of radiation received by the radiation receiver can be increased by viewing the path of the radiation with a gas having a lower radiation absorption rate than air.

  The radiation image generating apparatus according to claim 6 is characterized in that the radiation source includes a microfocus X-ray source.

  In this way, radiation is emitted so that the beam diameter is enlarged, so that a radiation image of the enlarged sample can be generated, and a complicated operation of observing the image using a microscope or the like can be performed. It can be made unnecessary.

  Since the present invention has the above-described configuration, it is possible to generate a radiation image of a living small experimental animal with a low exposure dose.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the radiation image forming apparatus 10 according to the present invention includes a shielding box 12, a radiation emitting unit 16, a sample storage member 30, a radiation receiving sheet 42 as a radiation receiver, and high-pressure means. The pump 44 and the gas tank 46 are provided.

  The shielding box 12 has a rectangular parallelepiped shape, and a gas filling space 14 is formed inside. The gas filling space 14 is sealed from the outside and sealed, and is filled with helium gas when in use.

  A radiation emitting unit 16 is disposed above the shielding box 12. Radiation X is emitted from the radiation emitting unit 16 toward the lower side of the shielding box 12. As the radiation X, a microfocus X-ray source, an X-ray source, or a γ-ray nuclide can be used. In the case of a microfocus X-ray source, the beam diameter of the radiation X emitted from the radiation emitting unit 16 is gradually expanded toward the lower side.

  A holding unit 20 is configured on the side of the shielding box 12 close to the radiation emitting unit 16. The holding part 20 has a concave shape that extends from one side of the shielding box 12 to the other side so as to cross the path of the radiation X, and a holding space 20R is formed in the concave. The holding space 20 </ b> R is isolated from the inside of the shielding box 12 by the isolation wall 22 and communicates with the outside. The holding space 20 </ b> R has a shape that follows the outer shape of the sample storage member 30 described later, and is configured to be slightly larger than the sample storage member 30.

  A deformation window 24 is formed in the holding unit 20. The deformation window 24 is configured in both the upper isolation wall 22 and the lower isolation wall 22 in the path of the radiation X in the holding unit 20. The deformation window 24 is formed by covering an opening formed in the isolation wall 22 with a flexible film that can transmit the radiation X. As a flexible film, an isobutylene isoprene copolymer (butyl rubber) (specific gravity 0.91 to 0.93) can be suitably used in terms of gas permeability resistance and X-ray permeability, but chloroprene rubber (specific gravity) 1.15 to 1.25) and chlorosulfonated polyethylene (specific gravity 1.18) can also be used. When the gas filling space 14 becomes a high pressure, the deformation window 24 is deformed so as to be curved toward the outside of the gas filling space 14, that is, the inside of the holding space 20R in the transmission direction of the radiation X.

  An image generation unit 40 is configured at a position where the radiation X transmitted through the holding unit 20 is irradiated near the bottom surface of the shielding box 12. The image generation unit 40 has a concave shape from one side where the holding unit 20 of the shielding box 12 is configured to the other side along the bottom surface of the shielding box 12, and a sheet arrangement space 40R is configured in the concave part. The sheet arrangement space 40 </ b> R is isolated from the inside of the shielding box 12. The sheet arrangement space 40R has a shape into which a later-described radiation receiving sheet 42 can be inserted.

  As shown in FIG. 1, the sample storage member 30 is a substantially elliptical cylindrical container, and as shown in FIGS. 2 and 4, a storage space 30 </ b> R that can store a sample T, which is a small experimental animal living inside, is configured. Has been. The sample storage member 30 can be arranged in the holding space 20R, and a pressing window 32 is formed at each position corresponding to the deformation window 24 when arranged in the holding space 20R.

  The pressing window 32 is formed by covering an opening formed at each position corresponding to the deformation window 24 with a flexible film that can transmit the radiation X. As a flexible film, an isobutylene isoprene copolymer (butyl rubber) (specific gravity 0.91 to 0.93) can be suitably used in terms of gas permeability resistance and X-ray permeability, but chloroprene rubber (specific gravity) 1.15 to 1.25) and chlorosulfonated polyethylene (specific gravity 1.18) can also be used. When the gas filling space 14 becomes high pressure and the deformation window 24 curves toward the inside of the holding space 20R, the pressing window 32 is pushed by the deformation window 24 and pushes the sample T toward the inside of the accommodation space 30R. Deforms to spread.

  A handle 34 is provided on one end surface of the sample storage member 30.

  As shown in FIG. 1, the radiation receiving sheet 42 has a plate shape, is fitted into a frame 43, and can be inserted into the sheet arrangement space 40 </ b> R. As the radiation receiving sheet 42, a photoreceptor sheet such as an X-ray film or a storage phosphor sheet can be used.

As shown in FIG. 2, a pump 44 and a gas tank 46 are connected to the gas filling space 14 of the shielding box 12. As shown in FIG. 3, the gas filling space 14 and the holding space 20 </ b> R are communicated with each other through a communication path 43 via a valve B <b> 1. The gas filling space 14 and the seat arrangement space 40R are communicated with each other through a communication passage 45 via a valve B2.
The gas tank 46 is filled with helium gas, and the helium gas in the gas tank 46 is supplied into the gas filling space 14 by the following procedure.
When filling with helium gas, first, the holding space 20R and the sheet arrangement space 40R are sealed with the lid 21 and the lid 41, respectively. And valve | bulb B1, B2 is open | released and the gas filling space 14 and holding | maintenance space 20R and the gas filling space 14 and sheet | seat arrangement | positioning space 40R are connected, respectively. Next, the pump 44 is operated, and the gas filling space 14 and the holding space 20R are evacuated. Then, helium gas is filled up to 1 atm from the gas tank 46 to the gas filling space 14, the holding space 20R, and the sheet arrangement space 40R. Thereafter, the valves B1 and B2 are closed, and the lid 21 and the lid 41 are opened.
In this way, the gas filling space 14 can be filled with helium.

  In the present embodiment, the gas filling space 14 is filled with helium gas, but it is not always necessary to use helium gas. Although it may be filled with air, it is preferable to fill with a gas (such as helium or hydrogen) having a lower radiation absorption rate than air.

  When the radiographic image forming apparatus 10 having the above configuration generates a radiographic image of the sample T, first, the sample T is accommodated in the accommodating space 30R of the sample accommodating member 30, as shown in FIGS. To do. At this time, the sample T is stored so that the observation target portion of the sample T is disposed at a position corresponding to the pressing window 32.

  Next, the sample storage member 30 that stores the sample T is arranged in the holding space 20R, and the radiation receiving sheet 42 is inserted and set in the sheet arrangement space 40R.

  Next, the pump 44 is operated, and helium gas is supplied from the gas tank 46 to the gas filling space 14 to make the gas filling space 14 high pressure. As a result, the deformation window 24 is deformed so as to be curved inward from the pressing window 32 of the sample storage member 30 by the pressure from the inside of the gas filling space 14 as shown in FIG. The pressing window 32 that has been pressed is also deformed so as to bend inward of the accommodation space 30R, and as shown in FIGS. 6A and 6B, the observation region of the sample T is pushed wide. Thereby, the observation site | part of the sample T becomes thinner than before spreading.

  Then, radiation X is emitted from the radiation emitting unit 16. The radiation X is irradiated onto the sample T, and the radiation X transmitted through the sample T is received by the radiation receiving sheet 42, and a radiation image is formed on the radiation receiving sheet 42.

  According to the present embodiment, by increasing the pressure of the gas filling space 14, the observation site of the sample T is expanded and deformed to reduce the thickness, so that the amount of transmission of the radiation X can be increased more than before the expansion. The radiation image of the sample T can be formed with a small amount of radiation, and the exposure amount of the sample T can be reduced.

  Further, since the sample storage member 30 for storing the sample T is disposed in the holding space 20R outside the gas filling space 14, air can be easily supplied to the sample T.

  In addition, since the gas-filled space 14 that is the path of the radiation X is filled with helium gas having a radiation absorption rate lower than that of air, the amount of radiation received by the radiation receiving sheet 42 can be increased.

  In this embodiment, the pressing window 32 of the sample storage member 30 is configured by disposing a flexible film in the opening. However, the pressing window 32 may be in an open state without a film.

  In this embodiment, the sample T is accommodated in the sample accommodating member 30 and the sample T is observed. However, the sample accommodating member 30 is not always necessary, and the sample T is directly accommodated in the holding space 20R for observation. May be performed.

  In this embodiment, an example of receiving radiation using the radiation receiving sheet 42 has been described. However, a digital radiation image may be formed using a device such as a CCD or a solid sensor.

  In the present embodiment, the example in which the sheet arrangement space 40R is isolated from the inside of the shielding box 12 has been described. However, the sheet arrangement space 40R may be provided in the gas filling space 14. In particular, as in the present embodiment, the radiation receiving sheet 42 can be easily set and removed by providing it outside the gas filling space 14.

As shown in FIG. 7, in the radiation image forming apparatus 10 described above, the distance from the position where the radiation X is emitted to the upper deformation window 24 is dxc, and the distance from the radiation receiving sheet 42 to the lower deformation window 24 is the distance. dsi, and the thickness of the sample T is ts. For each, the X-ray transmittance is calculated individually under the conditions of [Table 1]. Calculations are made using the “X-Ray Interactions With Matter Calculator” of the Lawrence Berkeley National Laboratory, X-ray Optical Center. As the material of the sample T, the value of water (H ₂ O) occupying 70% of the living body is calculated.

  From [Table 1], it is clear that the X-ray transmittance is higher when helium gas is filled than when the gas filling space 14 is filled with air, even at high pressure. Also, the lower the acceleration voltage, the greater the difference in X-ray transmittance.

It is clear that the thinner the sample T, the higher the X-ray transmittance. It can be seen that as the acceleration voltage is lower, the difference in X-ray transmittance is more conspicuous.
In addition, it is preferable to use an X-ray having only a photon energy of 15 keV or less obtained by an X-ray tube having a tube voltage of less than 20 kV in a sample obtained by spreading a living soft tissue to a thickness of about 10 mm.

1 is a schematic perspective view of a radiological image generation apparatus according to an embodiment of the present invention. 1 is a schematic cross-sectional view of a radiological image generation apparatus according to an embodiment of the present invention as viewed from the front. It is the figure which looked at the radiographic image generation apparatus at the time of helium filling from the side. 1 is a schematic cross-sectional view of a radiation image generating apparatus according to an embodiment of the present invention as viewed from the side. (A) which shows the state in which the sample was accommodated in the sample accommodation member is a schematic top view, (B) is a schematic sectional side view. FIG. 4A is a schematic top view and FIG. 4B is a schematic side sectional view showing a state in which a sample stored in a sample storage member is expanded and deformed. It is the schematic sectional drawing which looked at the radiographic image generation device concerning an example from the front.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Radiation image forming apparatus 12 Shielding box 14 Gas filling space 16 Radiation emitting part 20 Holding part 20R Holding space 24 Deformation window 30 Sample accommodation member 30R Accommodation space 32 Press window 40R Sheet arrangement space 40 Image generation part 42 Radiation receiving sheet 44 Pump 46 Gas tank T Sample

Claims (6)

A shielding box in which a gas-filled space blocked from the outside is configured;
High-pressure means for increasing the pressure of the gas-filled space;
A radiation source for emitting radiation from one side of the shielding box to the other side;
The high-pressure means communicates with the outside and is disposed in a path of radiation emitted from the radiation source so as to constitute a holding space through which the radiation is transmitted and in the gas-filled space in a direction through which the radiation is transmitted. A holding portion formed with a deformation window that can be deformed so as to bend toward the inside of the holding space by increasing the pressure at
An image generating unit disposed on a side opposite to the radiation source with respect to the holding unit and arranged with a radiation receiver that receives radiation transmitted through the sample;
A radiographic image generation apparatus comprising:   An accommodation space in which the sample is accommodated is configured and can be arranged in the holding space, and the accommodation is performed by pressing the deformation window at a position corresponding to the deformation window when the sample is arranged in the holding space. The radiographic image generation apparatus according to claim 1, further comprising: a sample storage member including a pressing window capable of expanding and deforming the sample stored in the space.   The radiation according to claim 2, wherein the pressing window includes a sealing member that can be deformed so as to bend toward the inside of the accommodation space by deformation of the deformation window. Image generation device.   The radiographic image generation apparatus according to claim 2, wherein the pressing window is an opening.   The radiographic image generation apparatus according to any one of claims 1 to 4, wherein the gas filling space is filled with a gas having a lower radiation absorption rate than air.   The radiographic image generation apparatus according to claim 1, wherein the radiation source includes a microfocus X-ray source.

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