KR200417270Y1 - Assembly for Radiation Shielding for Backscattered Radiation Attenuation in X-ray Imaging Facilities - Google Patents

Abstract

The present invention relates to a radiation shielding assembly for attenuating backscattered radiation in an X-ray imaging facility. More particularly, the present invention includes a lead plate at the rear of an X-ray detector installed in the X-ray imaging facility, and in front of the lead plate. Attenuation panels made of a material that is lighter than lead are sequentially provided in the order of atomic number from the direction of X-ray incidence, so that X-rays are gradually absorbed while causing a small amount of backscattering while passing through a number of attenuation panels. The present invention relates to a radiation shielding assembly in which the amount of X-ray backscattering scattered toward the subject is greatly reduced.

Radiation shielding assembly for the backscattered radiation attenuation in the X-ray imaging facility according to the present invention, the lead plate provided on the rear of the X-ray detector; Attenuation panels made of aluminum, iron or copper to attenuate scattering radiation; And a panel holder to which the lead plate and the attenuation panel are inserted and fixed, wherein the panel holder is formed of a depression-shaped frame in which a groove into which the lead plate and the attenuation panel are inserted is formed, and is formed on the front surface of the body. And two to four screw holes and a damage preventing rubber plate attached to the rear side of the screw holes.

The radiation shielding assembly for the backscatter radiation attenuation in the X-ray imaging facility according to the present invention has an effect of significantly reducing the amount of backscattered radiation of the X-rays to safely protect the subject from radiation exposure.

X-ray, backscatter, attenuation, shielding, assembly

Description

A shielding device module for reducing back-scattered radiation in X-ray exposure room

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the X-ray imaging facility in which a radiation shield is installed.

2 is a view showing the assembly structure of the radiation shielding assembly for the backscattered radiation attenuation in the X-ray imaging facility according to an embodiment of the present invention.

3 is a diagram illustrating a process of calculating the total amount of backscattered radiation.

<Description of the symbols for the main parts of the drawings>

10: X-ray source 20: Subject

30: X-ray detector 50: control room

100: primary shield 110: lead plate

121,122,123: attenuation panel 200: secondary shield

130: panel holder 131: fixing bolt

132: screw hole 136: wall mounting groove

The present invention relates to a radiation shielding assembly for attenuating backscattered radiation in an X-ray imaging facility. More particularly, the present invention includes a lead plate at the rear of an X-ray detector installed in the X-ray imaging facility, and in front of the lead plate. Attenuation panels made of a material that is lighter than lead are sequentially provided in the order of atomic number from the direction of X-ray incidence, so that X-rays are gradually absorbed while causing a small amount of backscattering while passing through a number of attenuation panels. The present invention relates to a radiation shielding assembly in which the amount of X-ray backscattering scattered toward the subject is greatly reduced.

In general, an X-ray photographing apparatus detects X-rays penetrating a subject with an X-ray detector and visualizes the inside of the subject. The X-ray photographing apparatus is variously used for diagnosis of a patient in a hospital or non-destructive testing of test materials in a laboratory. have.

In the X-ray imaging apparatus including the X-ray imaging apparatus therein, as shown in FIG. 1, direct radiation emitted from the X-ray source 10 and sequentially passing through the subject 20 and the X-ray detector 30 is provided. In order to prevent leakage to the outside provided with a primary shield 100 on the wall located behind the X-ray detector 30, further shielding the scattered radiation generated after the collision of the direct radiation and the primary shield 100 To this end, the secondary shield 200 is provided on all walls, ceilings and doors except for the rear of the X-ray detector 30.

In addition, a separate control room 50 is provided to allow the photographer to remotely control the X-ray generator including the X-ray source 10 and the X-ray detector 30.

Conventional primary shields (hereinafter, referred to only as primary shields are referred to as X-ray shields) are composed of lead plates, which lead to the excellent shielding effect against X-rays to absorb or scatter most of the X-rays. Because it has characteristics.

However, in the conventional primary shield made of lead only, back scattering occurs in which some of the X-rays reaching the shield are scattered back to the front side of the subject, and the back scattering causes the subject to be excessively exposed to radiation. There is a problem.

An object of the present invention is to solve the above problems. That is, a lead plate is provided at the rear of the X-ray detector, and attenuating panels made of a lighter material than lead are sequentially provided in the order of atomic number in descending order from the direction in which the X-ray is incident on the front surface of the lead plate. Full backscattering of X-rays is achieved by progressively absorbing while causing a small amount of backscattering while passing through the panel, and in turn allowing backscattered radiation, which originates in the rearmost leadplate and scatters towards the subject, in turn while passing through the front attenuation panel The purpose is to protect the subject by reducing the volume.

The present invention as a technical idea for achieving the above object,

A lead plate provided behind the X-ray detector;

Attenuation panels made of aluminum, iron or copper to attenuate scattering radiation; And

The lead plate and the attenuation panel is configured to include a panel holder is fixed and inserted,

The panel holder,

The lead plate and the damping panel is formed of a groove-shaped die-shaped frame is formed, characterized in that it comprises two to four screw holes formed in the front portion of the body, and a damage preventing rubber plate attached to the rear of the screw holes Provided is an assembly for radiation shielding for backscattered radiation attenuation in an X-ray imaging facility.

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

As shown in Figure 2, the radiation shielding assembly for the backscattered radiation attenuation in the X-ray imaging facility according to an embodiment of the present invention is provided on the rear of the X-ray detector so as not to leak to the outside by shielding the X-rays The lead plate 110 and the plurality of attenuation panels (121, 122, 123) provided between the lead plate and the X-ray detector to reduce the amount of scattered radiation, the lead plate 110 and the attenuation panel (121, 122, 123) ) Is configured as a panel holder 130 for supporting and fixing.

The attenuation panel is provided with plates made of a material lighter than lead. Preferably, the attenuation panel is laminated in the panel holder such that the attenuation panel is laminated in the order of the aluminum plate 123, the iron plate 122, and the copper plate 121 from the direction in which the X-ray is incident. By inserting and inserting a lead plate at the rear end, i.e., behind the copper plate 121, it is preferable to efficiently attenuate backscattered radiation by adjusting the number of panels for each material according to the energy of incident X-rays.

In general, a material having a low atomic number has a poor shielding ability against X-rays, but has a property of reducing energy of X-rays transmitted by scattering a small amount of radiation. Therefore, X-rays sequentially pass through aluminum plates, iron plates, and copper plates, which are elements of lighter weight than lead plates, before the X-rays reach the lead plates, gradually reducing the energy of the X-rays and reducing the energy of the X-rays from the lead plate. Most will be absorbed. Here, the low energy backscattered radiation that is not absorbed by the rearmost lead plate and scattered forward again is absorbed while passing through the copper plate, the iron plate, and the aluminum plate provided on the front surface of the lead plate in order to further reduce the amount.

The body of the panel holder 130 is a deformed frame with an open upper side, and grooves are formed at each side so that the lead plate 110 and the attenuation panels 121, 122, and 123 are left and right from the top to the bottom. It is inserted along the groove of the side and seated in the groove of the lower side. At least two screw holes 132 are formed on the front surface of the body, and fixing bolts 131 are fastened to the screw holes 132 to insert the attenuation panels 121, 122, and 123 inserted into the body of the panel holder 130. The lead plate 110 and the attenuation panels 121, 122, and 123 may be fixed by pressing the frontmost panel surface among them.

Here, a total of four screw holes 132 are formed at both the upper and lower sides of the front face of the body of the panel holder 130, and the attenuation panels 121 inserted into the body by fixing bolts 131 fastened to the panel holders 130, respectively. 122, 123) is to be fixed tightly. In addition, a damage prevention rubber plate (not shown) may be inserted into the rear of the screw hole 132 to prevent damage to the attenuation panels 121, 122, and 123 by the fixing bolt 131.

The radiation shielding assembly according to the present embodiment configured as described above may be installed in a floor or a wall or attached to a floor or a wall in various ways. When the wall is installed on the wall, a plurality of wall hangings are provided on the back of the body of the panel holder 130. The groove 136 may be formed to hang on a wall mount provided on the wall.

Hereinafter, the effect of backscatter radiation attenuation through the backscatter radiation attenuation shield in the X-ray imaging apparatus according to the present embodiment will be described in more detail.

When photons, such as X-rays or gamma rays, are irradiated on a particular object, the photons are the three reciprocals of the orbital electrons of the atoms that make up the object, the photoelectric effect, compton scattering, and pair production. React

Radiation in the photoelectric effect transfers all of the energy to the orbital electrons of the shield atoms and dissipates them. In addition, electron pair generation is a reaction in which photons disappear around a nucleus forming a strong electric field and generate negative electrons and positrons, and occurs when the energy of incident photons is 1.02 MeV or more, which is the static mass energy of the electron pair. Finally, Compton scattering is a reaction in which photons collide with each orbital electron and scatter at an irregular angle. The amount of photons scattered by Compton scattering can be expressed as a scattering cross section. The scattering cross-sectional area is a value representing the number of particles scattered at a constant scattering angle over a unit time relative to the number of particles incident during a unit time, and is expressed as a function depending on incident energy, atomic number and scattering angle.

Compton scattering is determined by the Klein-Nishina formula, which is widely known as an empirical formula, and the differential scattering cross section based on the Klein-Nishina formula can be expressed by Equation 1 below.

here,

σ : scattering cross section

Ω : solid angle

Z : atomic number

r _o : radius of the electron

α = E / ( m _o c ² )

E : X-ray energy

m _o : mass of the electron

θ : scattering angle

In Equation 1, the scattering angle θ is an angle formed by the advancing direction of the photons before the collision and the advancing direction of the photons after the collision, and solid angle Ω is used to determine the particles scattered at a specific unit scattering angle. An imaginary angle for consideration on a plane perpendicular to the axis, expressed as dΩ = 2πsin θdθ . Here, the backscattering corresponds to the case where the scattering angle θ is greater than 90 °.

As described above, the X-rays reaching the shield react with the atoms of the shield, and the intensity of the X-rays transmitted as it is without reacting with each other may be calculated by the shielding equation as shown in Equation 2 below.

I = I ₀ exp (-μd)

here,

I : X-ray intensity after penetrating the shield

I ₀ : X-ray intensity before penetrating the shield

μ : X-ray transmission constant of shield [cm ^-1 ]

d : thickness of the shield [cm]

In Equation 2, the X-ray transmission constant ( μ) of the shield is determined according to the material of the shield and the energy intensity of the incident X-ray, as shown in Table 1 below.

Comparison of transmission constants for X-ray energy and material of shield (unit: cm ^-1 ) Shield material X-ray energy 100 keV 300 keV 500 keV 1000 keV Polyethylene 0.155 0.110 0.090 0.065 Aluminum plate 0.462 0.281 0.228 0.166 iron plate 2.908 0.865 0.660 0.471 Copper plate 4.121 1.001 0.747 0.527 Lead plate 61.290 4.585 1.827 0.804

It can be seen from Table 1 that the smaller the element number and the larger the energy intensity of the X-rays, the more the amount of X-rays transmitted without being shielded by the shielding body increases.

When the X-rays are irradiated to the backscatter radiation attenuating shield of the X-ray imaging facility according to the present embodiment, the X-rays sequentially reach the plurality of attenuating panels and the lead plate, and simultaneously perform scattering and transmission. The backscattering amount for the radiation incident at is equal to (3) below, multiplied by the intensity of the radiation incident on the panel from the front and the backscattering cross-sectional area of the panel.

q = I × σ _b

here,

q : backscattering amount

I : intensity of incident radiation

σ _b : backscattering cross section

Therefore, when the scattering cross-sectional area and the transmission X-ray intensity in each panel are obtained using Equations 1 and 2, the amount of radiation back scattered in each panel can be calculated using Equation 3.

On the other hand, the radiation backscattered from the panel located in the rear is passed through the panels located in front of it in order to reduce the energy, since the radiation dose is proportional to the radiation intensity, the radiation after scattering radiation transmitted through each panel from Equation 1 Quantity can be obtained.

Therefore, the sum of the amount of backscattering in the foremost aluminum panel and the amount of radiation scattered back from each panel located behind it, penetrating again through the other panels in front of it, and irradiated back to the front, finally scatters toward the subject. It is possible to calculate the backscattering amount.

FIG. 3 is a diagram illustrating a process of calculating a backscattering cross-sectional area when an energy of incident X-rays is 100 keV and an aluminum plate, an iron plate, a copper plate, and a lead plate, each having a thickness of 1 mm, is laminated. Here, the X-rays passing through each attenuating panel are represented by solid lines, and the X-rays scattered from each attenuating panel are represented by dotted lines. Actually, all panels are in close contact with each other. Exaggeratedly spaced.

In FIG. 3, the scattering amount of X-rays scattered in each attenuation panel is calculated according to Equation 3, and the intensity and radiation dose of X-rays passing through each panel are calculated by Equation 2.

Thus, by calculating the amount of radiation transmitted or scattered in each attenuation panel, the total backscattering amount ( σ ₂ ) of the X-rays scattered toward the subject at the forefront of the shield can be calculated, which is 20.42 r _o ² I ₀ Becomes

On the other hand, when the shield is composed only of the lead plate it can be seen that the back scattering amount of the X-ray is 44.69 r _o ² I ₀ from the equation (3).

From this, it is possible to calculate the backscattered radiation reduction rate represented by Equation 4 below.

ρ = σ ₂ / σ ₁ * 100

here,

ρ : backscatter radiation reduction rate

σ ₁ : Backscattering amount after attenuating shield

σ ₂ : backscattering amount by the lead plate

When the incident X-ray energy is 100 keV, and a shield is formed by stacking three sheets of aluminum plate, iron plate, copper plate, and lead plate having a thickness of 1 mm for each material, the backscattered radiation reduction rate is calculated based on 47%. You can get the value.

As such, the results of calculating the backscattered radiation reduction rate for each energy intensity of the incident X-rays using Equations 1 to 4 are shown in Table 2 below.

Shield thickness X-ray energy 100 keV 300 keV 500 keV 12 mm (3 photos) 47 88 83 20 mm (5 photos) 37 63 62 28 mm (7 photos) 33 49 51 40 mm (10 photos) 28 39 42

Here, the thickness of each attenuation panel and lead plate of the shield was fixed to 1 mm, and the total thickness of the shield was reduced from 12 mm to 40 mm by changing the number of stacks of each plate to 3, 5, 7, 10. The backscattered radiation reduction rate was calculated for the case. For example, in the case where the number of sheets of each plate is three, the three plates of four materials each having a thickness of 1 mm are stacked, so that the total thickness of the shield is 12 mm.

Table 2 shows that even if the incident X-rays have a high energy level of 500 keV, the amount of scattered radiation can be reduced to about 40% by stacking 10 sheets of each panel and lead plate for each material.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the spirit of the present invention in the technical field to which the present invention belongs It will be clear to those of ordinary knowledge.

As described above, the X-ray imaging facility radiation shielding body for backscattered radiation attenuation according to the present invention has an effect that can significantly reduce the amount of backscattered radiation of the X-rays to safely protect the subject from radiation exposure.

In addition, as the amount of backscatter radiation generated from the primary shield of the X-ray imaging facility is reduced, the thickness of the secondary shield can be reduced, thereby facilitating the construction of the X-ray imaging facility, shortening the construction period, and reducing costs. It also works.

Claims (1)

In the radiation shielding assembly installed behind the X-ray detector of the X-ray imaging facility to block the X-rays from the outside, A lead plate provided behind the X-ray detector; Attenuation panels made of aluminum, iron or copper to attenuate scattering radiation; And The lead plate and the attenuation panel is configured to include a panel holder is fixed and inserted, The panel holder, The lead plate and the damping panel is formed of a groove-shaped die-shaped frame is formed, characterized in that it comprises two to four screw holes formed in the front portion of the body, and a damage preventing rubber plate attached to the rear of the screw holes An assembly for radiation shielding for backscattered radiation attenuation in an X-ray imaging facility.

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