KR102368704B1 - X-ray dose rate optimization of medical linear accelerator using pole / yoke type steering electromagnet - Google Patents

Abstract

The present invention relates to an apparatus for optimizing the X-ray dose of a medical linear accelerator and a medical linear accelerator using the same. In particular, an apparatus for optimizing the X-ray dose of a medical linear accelerator by using a steering electromagnet in the form of a pole and a yoke. It relates to a medical linear accelerator and a medical radiation generating device using the same.
In addition, according to the present invention, it is installed to surround the outside of the acceleration tube, the upper surface and the lower surface of the open box-shaped yoke portion to close so that the magnetic field is located inside; a pole part protruding inward in the form of a column at the center of each side of the yoke part; and an X-ray dose optimization device for a medical linear accelerator comprising a coil part wound in a columnar shape of the pole part formed in the center on each side of the yoke part and generating a magnetic field, and a medical linear accelerator and medical radiation generating device using the same.

Description

X-ray dose rate optimization of medical linear accelerator using pole / yoke type steering electromagnet}

The present invention relates to an apparatus for optimizing the X-ray dose of a medical linear accelerator and a medical linear accelerator using the same. In particular, an apparatus for optimizing the X-ray dose of a medical linear accelerator by using a steering electromagnet in the form of a pole and a yoke. It relates to a medical linear accelerator and a medical radiation generating device using the same.

A linear electron accelerator widely used as a medical radiation generator consists of an electron gun, an accelerator tube, an X-ray target, a vacuum system, a cooling system, and a power supply.

Electrons generated from the electron gun are accelerated to near the speed of light by a high-power high-frequency signal inside the accelerator tube, and the accelerated electron beam collides with an X-ray target mounted at the end of the accelerator tube to generate X-rays. ) will occur.

The electrons generated from the electron gun collide with the inner wall of the accelerator tube by disturbance factors such as structural bending of the accelerator tube, external magnetic field, and space charge effect while moving to the X-ray target. -ray) It may not collide with the target.

A steering electromagnet is used to prevent this electron beam reduction phenomenon, and it is possible to optimize the dose of X-rays generated from a medical linear accelerator by correcting the beam trajectory using a magnetic field generated from the steering electromagnet.

Steering electromagnets used in medical linear accelerators wind the coil a certain number of times and use the magnetic field generated by the current passing through the conductor. Install and use

In the existing steering electromagnet, a method of realizing a desired central magnetic field value by winding only a copper coil is widely used.

In many cases of linear accelerators to which the steering electromagnet is applied, the structural constraint required to obtain a desired magnetic field was not large, so the structural part of this steering electromagnet was not a problem. In the case of generators, the current structure of the steering electromagnet has room for improvement because it is becoming smaller and lighter in order to converge with real-time imaging devices or robot systems.

Leading companies in the development of medical radiation generators have developed and applied acceleration tubes based on high frequencies of the X-ray band to miniaturize the linear accelerators used as medical radiation generators. Various attempts are being made to minimize interference between devices.

Registration No. 10-1648972 Publication No. 10-2013-0135265 Publication No. 10-2016-0049425

The present invention has been devised to satisfy the above needs, and by producing a steering electromagnet in the form of winding a coil around a pole and a yoke to correct the trajectory of the electron beam, minimize the portion where the accelerated electron beam collides with the inner wall of the accelerator tube, To provide an X-ray dose optimizing device for a medical linear accelerator that ultimately optimizes the dose of X-rays generated from the linear accelerator by inducing them to collide with the optimal point of the X-ray target, a medical linear accelerator using the same, and a medical radiation generating device .

One aspect of the present invention is installed to surround the outside of the acceleration tube, the upper surface and the lower surface of the open box-shaped yoke portion to close the magnetic field to be located inside; a pole part protruding inward in the form of a column at the center of each side of the yoke part; and a coil part wound on the pillar shape of the pole part formed in the center on each side of the yoke part and generating a magnetic field.

In addition, the yoke part and the pole part of one aspect of the present invention are formed of pure iron.

In addition, the yoke portion of one aspect of the present invention is a plate-shaped upper yoke having an opening for allowing the upper inner coil and the upper outer coil to be exposed to the outside; a lower yoke having an opening for allowing the lower inner coil and lower outer coil to be exposed to the outside; a left yoke having an opening for allowing the left inner coil and the left outer coil to be exposed to the outside; and a right yoke having an opening for allowing the right inner coil and the right outer coil to be exposed to the outside.

In addition, the upper yoke, the left yoke, the right yoke and the lower yoke of one aspect of the present invention are coupled by a connecting member.

In addition, the upper yoke, the lower yoke, the left yoke and the right yoke of one aspect of the present invention are integrally formed.

In addition, the pole part of one aspect of the present invention is an upper pole core which is attached toward the inside in the center of the upper yoke in a columnar shape; a lower pole core attached toward the center of the lower yoke in a columnar shape; a left pole core attached toward the center of the left yoke in a columnar shape; and a right pole core attached to the center of the right yoke in a columnar shape toward the inside.

In addition, the upper pole core of one aspect of the present invention is formed at the end of the column shape, the upper pole core head formed to protrude to the outside; The lower pole core may include a lower pole core head formed at an end of a column shape to protrude to the outside; The left pole core may include a left pole core head formed at an end of a column shape to protrude to the outside; and a right pole core head formed at an end of the column shape to protrude to the outside of the right pole core.

In addition, the upper pole core and the upper yoke of one aspect of the present invention are connected by a connecting member, the lower pole core and the lower yoke are connected by a connecting member, and the left pole core and the left yoke are connected They are connected by a member, and the right pole core and the right yoke are connected by a connecting member.

In addition, one aspect of the present invention is attached to the outer surface of the lower yoke and further includes a protection part having a groove for protecting the lower inner coil and the lower outer coil from the outside.

In addition, one aspect of the present invention is installed on the outer surface of the upper yoke, and receives power from an external power supply and provides current through the upper inner coil, lower inner coil, left inner coil and right inner coil to the coil unit. It further includes a terminal block for connecting the power supply for supplying.

On the other hand, another aspect of the present invention is an accelerator tube for accelerating the incident electron beam emitted from the cathode; and a first yoke part installed on the inlet side to surround the outside of the acceleration tube, and closed in a box shape with an upper surface and a lower surface open so that a magnetic field is located therein, and the first yoke part in the center on each side of the first yoke part It includes a first steering electromagnet having a first pole part protruding in the shape of a column and a first coil part which is wound on the column shape of the first pole part formed in the center on each side of the first yoke part and generates a magnetic field. .

In addition, another aspect of the present invention is a second yoke unit installed on the outlet side to surround the outside of the acceleration tube, and closing the upper and lower surfaces in a box-like shape so that a magnetic field is located therein, and the second yoke unit. 2 A second pole part protruding inside in a columnar shape from each side of the yoke part, and a second coil part wound on a columnar shape of the second pole part formed in the center on each surface of the second yoke part and generating a magnetic field It further includes a second steering electromagnet.

The present invention, as described above, minimizes the portion where the accelerated electron beam collides with the inner wall of the accelerator tube by correcting the trajectory of the electron beam by manufacturing a steering electromagnet in the form of winding a coil around a pole and yoke made of pure iron, and is located at the optimal point of the X-ray target. By inducing the collision, the dose of X-rays generated from the linear accelerator can be finally optimized.

In general, a radiation generating device used as a medical device includes, in addition to a linear accelerator, a cooling system, a vacuum system, a power system, a control and monitoring system, and various other devices installed in a limited space.

If a steering electromagnet is manufactured using a yoke and pole made of pure iron, it is possible to generate a magnetic field of the same strength even with a relatively small size of a steering electromagnet. It is possible to shield the electron beam acceleration inside the accelerator tube from the magnetic field interference from the magnetron or the earth magnetic field.

Conversely, since the leakage magnetic field leaking out from the steering electromagnet is smaller than the conventional method, the magnetic field interference to external equipment is small.

In other words, if the proposed method is applied, there is an advantage in that it is possible to shield the interference phenomenon from disturbance elements while satisfying the spatial constraints.

1 is a block diagram of an apparatus for optimizing an X-ray dose of a medical linear accelerator, a medical linear accelerator and a medical radiation generating apparatus using the same according to a preferred embodiment of the present invention.
FIG. 2 is a structural diagram of the steering electromagnet of FIG. 1 .
3 is an exploded view of the yoke and the pole core of FIG. 2 .
4 shows structural modeling of a conventional steering electromagnet.
5 is a view showing a CST simulation result according to a conventional method.
6 shows structural modeling of a steering electromagnet according to the present invention.
7 is a view showing a CST simulation result according to the present invention.

In order to explain the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, preferred embodiments of the present invention will be exemplified below and will be described with reference to them.

First, the terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention, and the singular expression may include a plural expression unless the context clearly indicates otherwise. In addition, in this application, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other It should be understood that this does not preclude the possibility of addition or presence of features or numbers, steps, operations, components, parts, or combinations thereof.

In describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a block diagram of an apparatus for optimizing an X-ray dose of a medical linear accelerator, a medical linear accelerator and a medical radiation generating apparatus using the same according to a preferred embodiment of the present invention.

1, the medical radiation generating device according to a preferred embodiment of the present invention, the cathode 100, the grid 110, the anode 120, the accelerator tube 130, the first steering electromagnet 140, It includes a second steering electromagnet 150 , a focusing solenoid 160 , a target 170 , a filter 180 , and a multi-leaf collimator (MLC) 190 .

The cathode 100 is positioned at the center of rotation and when a high voltage is applied, hot electrons are emitted in the right direction of the drawing.

When the electron gun is small, the cathode 100 of the dispenser type is used and has a draw current of several tens of mA to several hundreds of mA.

The electron beam due to the hot electron emission has a low energy of several eV on the surface of the cathode 100, and initially the hot electrons of low energy are emitted at various angles along the surface of the cathode 100, and are straight by the direction of the electric field applied to the electron gun be able to have

The anode 120 forms an electron beam by limiting the direction and diffusion of hot electrons emitted from the cathode 100 .

The accelerator tube 130 has straightness and accelerates the incident electron beam to high energy.

In addition, the first steering electromagnet 140 is installed on the inlet side of the accelerator tube 130 and functions as a bundler steering electromagnet for bunching the incident electron beam.

Accordingly, the electron beam gradually increases the size of the bunch together with the space charge effect. Therefore, it is very important for an electron accelerator to minimize the divergence of the initial energy electron beam, which is very sensitive to the strength of the electromagnetic field and the magnetic field.

Meanwhile, the second steering electromagnet 150 is installed on the exit side of the acceleration tube 130 to adjust the direction of the electron beam to optimize the X-ray dose.

The target 170 includes a target material that emits X-rays when the electron beam collides, and emits X-rays when the limited electron beam collides.

In addition, the filter 180 is disposed between the target 170 and the subject to which the X-rays are transmitted, and removes low-energy X-rays.

When the field of vew (FOV) for the ROI of the subject is determined, the multi-leaf collimator 190 collimates the X-rays irradiated from the X-ray source to reach only the ROI of the subject.

As described above, in the medical radiation generating device according to an exemplary embodiment of the present invention, electrons generated from an electron gun are accelerated close to the speed of light by a high-power high-frequency signal inside the accelerator tube 130, and the accelerated electron beam is accelerated through the accelerator tube. It collides with the target 170 mounted at the end to generate X-rays.

The electrons generated from the electron gun collide with the inner wall of the accelerator tube 130 while moving to the X-ray target 170 due to disturbance factors such as structural bending of the accelerator tube 130, external magnetic field, and space charge effect. There is a case where it cannot accurately collide with the X-ray target 170. In order to prevent this electron beam reduction phenomenon, the first steering electromagnet 140 and the second steering electromagnet 150 are used, and the first steering electromagnet 140 is used. And it is possible to optimize the dose of X-rays generated from the medical linear accelerator by correcting the trajectory of the beam using the magnetic field generated from the and second steering electromagnet 150 .

FIG. 2 is a structural diagram of the steering electromagnet of FIG. 1 .

Referring to FIG. 2 , the steering electromagnet of FIG. 1 includes a yoke unit 200 , a pole unit 210 , a coil unit 220 , a terminal block 230 , and a protection unit 240 .

The yoke unit 200 is formed in a box-shaped shape with an open upper surface and a lower surface, and is closed so that the magnetic field formed by the coil unit 220 does not leak to the outside.

The yoke unit 200 is a plate-shaped upper yoke 201 having an opening 201-1 for allowing the upper inner coil 221-1 and the upper outer coil 222-2 to be exposed to the outside; A lower yoke 202 having an opening (not shown) for allowing the lower inner coil (not shown) and the lower outer coil (not shown) to be exposed to the outside, the left inner coil (not shown) and the left outer coil ( so that the left yoke 203 and the right inner coil 224-1 and the right outer coil 224-2 having an opening (not shown) for allowing the outside) to be exposed to the outside can be exposed to the outside A right yoke 204 provided with an opening 204-1 for disposing is provided.

The upper yoke 201, the left yoke 203, and the right yoke 204 are connected by a screw 201-2. Here, the screw is an example of the connecting member and may be connected through an adhesive other than the screw.

The lower yoke 202 and the left yoke 203 and the right yoke 204 are also connected by screws (not shown). Here, the screw is an example of the connecting member and may be connected through an adhesive other than the screw.

As described above, the yoke unit 200 includes the upper yoke 201, the lower yoke 202, the left yoke 203, and the right yoke 204 are individually manufactured and connected by a connecting member, but may be manufactured integrally. .

In addition, on the outer surfaces of the upper yoke 201, the lower yoke 202, the left yoke 203 and the right yoke 204 of the yoke unit 200, an upper pole core (not shown), a lower pole core 212, Groove portions 201-4 and 204-4 into which the nuts 201-3 and 204-3 can be inserted so that the left pole core 213 and the right pole core (not shown) can be attached by bolts (not shown). ) is provided.

The pole part 210 protrudes in a central column shape from each side of the yoke part 200 , and the protruding column shape may be a square column shape.

The pole part 210 includes an upper pole core (not shown), a lower pole core 212 , a left pole core 213 , and a right pole core (not shown).

The upper pole core (not shown), the lower pole core 212, the left pole core 213, and the right pole core (not shown) have a columnar shape, respectively, in an upper yoke 201, a lower yoke 202, and a left yoke ( 203) and the inside of the center of the right yoke 204, the attachment method may be attached by a bolt.

Referring to FIG. 3 showing this in more detail, the right pole core 214 is fixed to the right yoke 204 through two bolts 204-5.

To this end, the right pole core 214 has a tab inside, and the right yoke 204 has a hole 204-6, so that the bolt 204-5 is attached to the right yoke 204. ) through the hole 204-6 formed in the pole core 214 is fastened by a tab inside the right side.

Here, the bolt is an example of the connecting member, and may be attached by an adhesive.

Of course, since the right pole core 214 and the right yoke 204 are integrally formed, a separate connection member may not be required.

The right pole core 214 has a right pole core head 214-2 that is formed to protrude outward from the lower pillar, so that the winding right coil does not easily deviate.

Although the right yoke 204 and the right pole core 214 have been described with reference to FIG. 3 above, the upper yoke 201, the upper pole core 211, the lower yoke 202, the lower pole core 212, and the left The structures of the yacht 203 and the left pole core 213 are also the same.

Meanwhile, the coil unit 220 is wound in a columnar shape formed on each surface of the yoke unit 200 of the pole unit 210 to generate a magnetic field.

The coil unit 220 includes an upper coil 221 wound around the upper pole core 211 , a lower coil 222 wound around the lower pole core 212 , and a left coil 223 wound around the left pole core 213 . ) and a right coil 224 wound around the right pole core 213 .

The upper coil 221 is connected to the terminal block 230 and includes an upper inner coil 221-1 that receives power supplied from the outside, and an upper outer coil 221-2 that outputs the received power.

In addition, the lower coil 222 is connected to the terminal block 230 and includes a lower inner coil (not shown) receiving power supplied from the outside and a lower outer coil (not shown) outputting the received power.

In addition, the left coil 223 is connected to the terminal block 230 and includes a left inner coil (not shown) that receives power supplied from the outside, and a left outer coil (not shown) that outputs the received power.

In addition, the right coil 224 is connected to the terminal block 230 and includes a right inner coil 224-1 that receives power supplied from the outside, and a right outer coil 224-2 that outputs the received power, there is.

On the other hand, the terminal block 230 has a socket connected to the external power supply and a socket connected to the inner coil, so that the current received from the external power supply can be supplied to the coil unit.

In addition, the protection unit 240 is to protect the lower inner coil and lower outer coil exposed to the outside from being connected to the outside, and a groove 240-1 in which the lower inner coil and lower outer coil can be located is formed. there is.

In this configuration, the yoke part 200 and the pole part 210 are formed of pure iron.

Figure 4 shows the structural modeling of the steering electromagnet according to the conventional method, Figure 5 is a view showing the CST simulation result according to the conventional method, Figure 6 shows the structural modeling of the steering electromagnet according to the present invention, Figure 7 is the present invention As a drawing showing the CST simulation results according to It is the result of comparative analysis.

The position of the coil for the steering electromagnet was arranged assuming an acceleration tube with a size of 65 mm in width and 65 mm in length.

The value of the magnetic field at the center of the accelerator tube through which the beam passes is measured to be about 23 gauss in the case of the conventional method.

On the contrary, in the case of the proposed method, it was found to be about 40 Gauss, and the magnetic field leaking to the outside of the steering electromagnet was relatively small.

Usually, in a medical linear accelerator, the electron beam is accelerated through the space inside the accelerator tube, which is several millimeters.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Therefore, the embodiments described in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: cathode 110: grid
120: anode 130: accelerator tube
140: first steering electromagnet 150: second steering electromagnet
160: focusing solenoid 170: target
180: filter 190: multi-leaf collimator
200: yoke unit 210: pole unit
220: coil unit 230: terminal block
240: protection

Claims (13)

a yoke unit installed to surround the outside of the accelerator tube, and closing the upper and lower surfaces of the box in an open box shape so that the magnetic field is located therein;
a pole part protruding inward in the form of a column at the center of each side of the yoke part; and
It is wound on the pillar shape of the pole part formed in the center on each side of the yoke part and includes a coil part for generating a magnetic field,
The yoke part
an upper yoke having an opening for exposing the upper inner coil and the upper outer coil to the outside in a plate shape;
a lower yoke having an opening for allowing the lower inner coil and lower outer coil to be exposed to the outside;
a left yoke having an opening for allowing the left inner coil and the left outer coil to be exposed to the outside; and
It includes a right yoke having an opening for allowing the right inner coil and the right outer coil to be exposed to the outside,
The apparatus for optimizing the X-ray dose of a medical linear accelerator further comprising a protection part attached to the outer surface of the lower yoke and having a groove for protecting the lower inner coil and the lower outer coil from the outside. The method according to claim 1
The yoke portion and the pole portion is an X-ray dose optimization device of a medical linear accelerator formed of pure iron. delete The method according to claim 1,
The upper yoke, the left yoke, the right yoke, and the lower yoke are coupled to each other by a connecting member, an X-ray dose optimization device for a medical linear accelerator. The method according to claim 1,
The upper yoke, the lower yoke, the left yoke and the right yoke are an X-ray dose optimization device for a medical linear accelerator that is integrally formed. The method according to claim 1,
The pole part
an upper pole core attached toward the center of the upper yoke in a columnar shape;
a lower pole core attached toward the center of the lower yoke in a columnar shape;
a left pole core attached toward the center of the left yoke in a columnar shape; and
An X-ray dose optimization device for a medical linear accelerator comprising a right pole core attached toward the inside in the center of the right yoke in a column shape. 7. The method of claim 6,
The upper pole core may include an upper pole core head formed at an end of a column shape to protrude to the outside;
The lower pole core may include a lower pole core head formed at an end of a column shape to protrude to the outside;
The left pole core may include a left pole core head formed at an end of a column shape to protrude to the outside; and
The right pole core is formed at the end of the column shape, and the X-ray dose optimization apparatus of the medical linear accelerator including a right pole core head formed to protrude to the outside. 7. The method of claim 6,
The upper pole core and the upper yoke are connected by a connecting member, the lower pole core and the lower yoke are connected by a connecting member, the left pole core and the left yoke are connected by a connecting member, and the right The pole core and the right yoke are connected to each other by a connecting member, an X-ray dose optimization device for a medical linear accelerator. delete a yoke unit installed to surround the outside of the accelerator tube, and closing the upper and lower surfaces of the box in an open box shape so that the magnetic field is located therein;
a pole part protruding inward in the form of a column at the center of each side of the yoke part;
It is wound on the pillar shape of the pole part formed in the center on each side of the yoke part and includes a coil part for generating a magnetic field,
The yoke part
an upper yoke having an opening for exposing the upper inner coil and the upper outer coil to the outside in a plate shape;
a lower yoke having an opening for allowing the lower inner coil and lower outer coil to be exposed to the outside;
a left yoke having an opening for allowing the left inner coil and the left outer coil to be exposed to the outside; and
It includes a right yoke having an opening for allowing the right inner coil and the right outer coil to be exposed to the outside,
It is installed on the outer surface of the upper yoke, receives power from an external power supply, and supplies a current to the coil unit through the upper inner coil, lower inner coil, left inner coil and right inner coil. An X-ray dose optimization device for a medical linear accelerator further comprising a terminal block. an accelerator tube for accelerating an incident electron beam emitted from the cathode; and
A first yoke portion installed on the inlet side to surround the outside of the acceleration tube, and closed in a box-like shape having an upper surface and a lower surface open so that a magnetic field is located therein, and a pillar in the center on each surface of the first yoke portion A first steering electromagnet having a first pole portion protruding inward in a shape and a first coil portion for generating a magnetic field is wound on the pillar shape of the first pole portion formed in the center on each side of the first yoke portion. ,
The first yoke unit
an upper yoke having an opening for exposing the upper inner coil and the upper outer coil to the outside in a plate shape;
a lower yoke having an opening for allowing the lower inner coil and lower outer coil to be exposed to the outside;
a left yoke having an opening for allowing the left inner coil and the left outer coil to be exposed to the outside; and
It includes a right yoke having an opening for allowing the right inner coil and the right outer coil to be exposed to the outside,
The first steering electromagnet is
A medical linear accelerator using an X-ray dose optimization device of a medical linear accelerator, which is attached to the outer surface of the lower yoke and further includes a protective part having a groove formed thereon to protect the lower inner coil and lower outer coil from the outside. 12. The method of claim 11,
A second yoke unit installed on the outlet side to surround the outside of the acceleration tube and closed so that the magnetic field is located therein in an open box shape with upper and lower surfaces, and a pillar in the center on each side of the second yoke unit A second steering electromagnet having a second pole portion protruding inward in a shape and a second coil portion for generating a magnetic field wound in the shape of a column of the second pole portion formed in the center on each side of the second yoke portion A medical linear accelerator using an X-ray dose optimization device of a medical linear accelerator. a cathode emitting an electron beam when a high voltage is applied;
an accelerator tube for accelerating an incident electron beam emitted from the cathode;
A first yoke portion installed on the inlet side to surround the outside of the acceleration tube, and closed in a box-like shape having an upper surface and a lower surface open so that a magnetic field is located therein, and a pillar in the center on each surface of the first yoke portion a first steering electromagnet including a first pole part protruding inward in a shape and a first coil part wound in a column shape of the first pole part formed in the center on each surface of the first yoke part and generating a magnetic field;
A second yoke unit installed on the outlet side to surround the outside of the acceleration tube and closed so that the magnetic field is located therein in an open box shape with upper and lower surfaces, and a pillar in the center on each side of the second yoke unit a second steering electromagnet including a second pole part protruding in the shape of a second pole part and a second coil part wound in a column shape of the second pole part formed in the center on each surface of the second yoke part and generating a magnetic field; and
To include a target that emits X-rays when the electron beam emitted from the exit of the acceleration tube collides,
The first yoke unit
an upper yoke having an opening for exposing the upper inner coil and the upper outer coil to the outside in a plate shape;
a lower yoke having an opening for allowing the lower inner coil and lower outer coil to be exposed to the outside;
a left yoke having an opening for allowing the left inner coil and the left outer coil to be exposed to the outside; and
It includes a right yoke having an opening for allowing the right inner coil and the right outer coil to be exposed to the outside,
The first steering electromagnet is
A medical radiation generating device using an X-ray dose optimization device of a medical linear accelerator, which is attached to the outer surface of the lower yoke and further includes a protection part having a groove formed therein for protecting the lower inner coil and the lower outer coil from the outside.

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