KR20200082994A - Scattered radiation shielding structures using slits or girds - Google Patents

Abstract

The present invention relates to a structure for shielding the leakage of scattered radiation due to a duct penetrating a shielding wall and is to replace the existing duct shielding method that requires large cost and construction period for installation. When the structure proposed in the present invention is manufactured with the same cross-sectional size as the duct, a shielding effect can be adjusted by adjusting the length of the structure.

Description

Scattered radiation shielding structures using slits or girds}

The present invention is an open space such as radiation ducts generated inside a facility using a high dose of radiation, such as a radiation oncology department of a hospital, an imaging department of a hospital, a laboratory performing non-destructive testing, and a radiation irradiation facility for sterilization or molecular structure change. It relates to a structure that prevents leakage to the outside of the facility through, more specifically, to a structure that shields scattered radiation while maintaining the flow of air by arranging metal or non-metallic materials in a slit or lattice form.

In facilities using high doses of radiation, in order to prevent radiation from leaking to the outside, a closed structure is installed so that the inside where the radiation source is installed and the outside where radiation should not be exposed are physically partitioned.

However, in an environment where ventilation is essential, such as a hospital, a duct is installed for ventilation, and a hole is formed between the inside where the radiation source is installed and the outside where radiation should not be exposed, and the scattered radiation is emitted through the hole. do.

In this case, in general, an additional shield is installed in the duct as shown in FIG. 1, or the duct is installed in a folded maze structure as shown in FIG. 2 to reduce the amount of scattered radiation leaking to the outside below the legal limit.

In the method of FIG. 1, a lead plate is mainly used, and there is inconvenience in that a large cost and air are required to install a support for fixing a heavy additional shield to the ceiling, and the method of FIG. 2 cannot be applied unless it is reflected in the initial design of the building. Do.

Therefore, even though a large cost and air consumption are hitherto, the method of FIG. 1 is used to reduce external leakage of radiation.

The present invention has been devised in consideration of the above-mentioned conventional problems, and its purpose is to shield the scattered radiation generated when the radiation radiated from the radiation source is reflected on the inner wall of the use facility or the patient's body, and at the same time, the air flow. It is a duct connection structure to keep it.

In the above-mentioned radiation use facility, X-rays of 18 MeV or less, or gamma rays having the same physical properties as X-rays are used, and the scattered radiation scattered when the radiation collides with the material decreases energy by Equation 1, as shown in Table 1. It will have an energy of 0.50 MeV or less.

here,

hv': energy of scattered radiation (MeV)

hv: Energy of incident radiation (MeV)

θ: Scattering angle. 0° when there is no change in the direction of radiation, and 180° when returning to the incident direction.

m ₀ : static mass of electron

c: speed of light

The energy distribution of scattered radiation that has collided with a material. When the scattering angle is less than 90 degrees, the traveling direction of the scattering radiation is inside the colliding material, so it is not considered. Incident radiation energy (MeV) Scattering angle (°) Scattered radiation energy (MeV) One 90 0.34 120 0.25 180 0.20 9 90 0.48 120 0.33 180 0.25 18 90 0.50 120 0.33 180 0.25

Since the energy of the scattered radiation generated by interaction with the material is less than 1.02 MeV, a bi-generation reaction that generates X-rays of 0.511 MeV does not occur, and a photoelectric effect in which the probability of occurrence is inversely proportional to the third power of energy occurs.

Since the photoelectric effect converts all the energy of the incident radiation into an easily absorbable photoelectron, the incident radiation is attenuated with very high efficiency.

In other words, since the radiation emitted from the radiation source is reflected after colliding with the patient's body or the inner wall of the facility, the scattered radiation has an energy of 0.50 MeV or less. Lose energy

Particularly, since the photoelectric effect is proportional to the fourth power of the atomic number, the effect becomes even greater when the metals collide obliquely.

Using this principle, if a metal plate is placed in the form of a horizontal slit or a vertical slit, or in a lattice shape that simultaneously maintains a horizontal slit and a vertical slit, the scattering line can be effectively shielded without blocking the flow of air. Can.

Through the present design, instead of a duct additional shielding method for installing additional shields of heavy weight in the field or a maze-shaped shield requiring a lot of space, it is manufactured at the factory, and the field installation is simple, occupies less space, and has high shielding performance It enables scattered radiation to be shielded.

1 is a cross-sectional view of an existing duct reinforcement method that additionally shields the front and rear parts of the duct.
2 is a cross-sectional view of an existing shielding method that prevents leakage through a duct by making the shielding wall a maze structure.
Figure 3 is an example and a cross-sectional view of the vertical slit-shaped structure installed in the duct
4 is a horizontal slit structure and cross-sectional view
5 is a lattice-shaped structure and cross-sectional view

Specific structural or functional descriptions of the embodiments according to the concept of the present invention disclosed in this specification are exemplified only for the purpose of explaining the embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention It can be implemented in various forms and is not limited to the embodiments described herein.

Embodiments according to the concept of the present invention can be applied to various changes and can have various forms, so the embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosure forms, and includes all modifications, equivalents, or substitutes included in the spirit and scope of the present invention.

In addition, the thickness of the layers and regions in the drawings is exaggerated for clarity.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings.

3 is a view schematically showing a general embodiment of the present invention. It is a slit-shaped structure 5 and a cross-section 51 in the duct 3. The horizontal slit-shaped structure 5 is installed at a portion where the duct 3 penetrates the shielding wall 4, and the length of the horizontal slit-shaped structure 5 may be shorter or longer than the shielding wall 4. That is, the horizontal slit-shaped structure 5 serves as a duct 3 which is a passage through which air flows, and is used to simultaneously serve as a shielding wall 4 for shielding scattered radiation.

4 is a vertical slit structure 6 and a cross-sectional view 61. When irradiating the radiation downward, when the horizontal slit-shaped structure 5 is installed close to the radiation source, a shielding effect of 80 to 99% appears depending on the location. On the other hand, when the vertical slit structure 6 is installed, it is fixed at 98%. That is, according to the irradiation direction of the radiation source and the installation position of the structure, a horizontal slit structure 5 and a vertical slit structure 6 are selectively used to ensure shielding homeostasis.

5 is a lattice-shaped structure 7 and a cross-sectional view 71 having the characteristics of the horizontal slit-shaped structure 5 and the vertical slit-shaped structure 6 at the same time. As described above, since the shielding efficiency varies depending on the irradiation direction of radiation, in a facility where the radiation irradiation direction is changed, the shielding efficiency is prevented by using a lattice-shaped structure 7 to prevent the reduction of the shielding efficiency due to the change in the irradiation direction. Guarantees homeostasis.

The material of the horizontal slit-shaped structure 5, the vertical slit-shaped structure 6 and the lattice-shaped structure 7 may be metal, ceramic, polymer, or glass, or a single material or alloy thereof. .

The spacing between the slits and the grids of the horizontal slit-shaped structure 5, the vertical slit-shaped structure 6, and the lattice-shaped structure 7 may be 1 mm to 1 cm, but is not limited thereto.

If the structure proposed in the present invention is manufactured to have a cross-sectional size such as a duct, the shielding effect can be adjusted by adjusting the length of the structure. Therefore, the length of the slit and the lattice of the horizontal slit-shaped structure 5, the vertical slit-shaped structure 6, and the lattice-shaped structure 7 may be 1 cm to 30 cm, but is not limited thereto.

The directions of the slits constituting the horizontal slit-shaped structure 5 and the vertical slit-shaped structure 6 are not necessarily limited to horizontal or vertical, and may have various angles.

Although the shape of the lattice-shaped structure 7 and the section through which the air flows in the cross section 71 is indicated by a square in the drawing, the shape of the pattern may vary. The shape of the pattern can be circular or any polygonal shape (eg, triangular, square, pentagonal, hexagonal, octagonal, etc.). Holes having any of these shapes may be formed in a certain pattern, such as a lattice pattern or a honeycomb pattern.

Although the preferred embodiments have been illustrated and described above, the present invention is not limited to the embodiments of the above-described features, and the general knowledge in the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Of course, various modifications can be made by a person who has it, and these modifications should not be individually understood from the technical spirit or prospect of the present invention.

1: Additional shield surrounding the duct. Lead plate, usually tied with stainless steel band
2: ceiling
3: Duct
4: Shield wall. Generally, thick concrete wall surface for radiation shielding
5: vertical slit structure
51: Cross section of vertical slit structure
6: Transverse slit structure
61: cross section of horizontal slit structure
7: Lattice structure
71: cross-section of a grid-like structure

Claims (1)

In the shielding body for preventing the scattered radiation from leaking to the outside through a space such as a duct in a radiation use facility,
Multiple slit or grid structures are used repeatedly,
The spacing of the slits and grids is between 1 mm and 1 cm,
The length of the slit and grid is between 1 cm and 30 cm,
Scattered radiation shielding structure characterized in that the material is a single material or alloy of metal, ceramic, polymer, or glass.

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