HK1195618B - Radiation-emitting device and the imaging system - Google Patents

Description

Ray emission device and imaging system

Technical Field

The invention relates to a ray emitting device and an imaging system.

Background

In the nuclear technology imaging application, an object can be scanned point by using a modulated ray pen beam, a detector receives a scanned signal, and an image reflecting object information can be obtained by corresponding the scanning position and the signal during data processing. The most critical component in this type of application is the implementation of a flying spot scanning mechanism that constrains the radiation modulation and enables scanning.

The existing flying spot scanning mechanism is that a rotary shielding body with multiple collimation holes rotates in a ray scanning sector to realize scanning of a first dimension, and the ray scanning sector rotates or translates to realize scanning of a second dimension. For the first dimension scanning, rays are scanned on a vertical plane object at a non-uniform speed, scanning lines are accelerated at the starting end and the tail end of scanning, scanning spots can be further expanded longitudinally on the basis of geometric deformation, and longitudinal compression deformation caused by scanning speed change besides the geometric deformation is caused. When the second-dimension scanning is carried out, a translation ray generating device and a rotary shielding body are needed when a translation ray scanning sector is selected, and the mechanical structure is very complex; the choice of a rotating radiation scanning sector requires overcoming the moment of inertia of the rotating shield, which is a great challenge for the rotating drive and the bearings of the rotating shield. Also, since in this technique the radiation source, e.g. the X-ray machine, is generally arranged inside the rotating radiator, it is difficult to form a matching interface with the existing X-ray machine, and the shielding of the X-ray machine needs to be redesigned, which increases the cost of the backscatter scanning imaging apparatus.

Another existing flying spot scanning mechanism consists of a fixed shield plate and a rotating shield in front of the radiation source. The stationary shield is stationary with respect to the source and the rotating shield is rotatable with respect to the stationary shield. The rotating shield is generally disc-shaped. The fixed shielding plate and the rotary shielding body are respectively provided with a linear gap and a spiral line gap, in the rotary scanning process of the rotary shielding body, the linear gap and the spiral line gap are continuously intersected to form a scanning collimation hole, and the scanning collimation hole is always kept in a preset shape relative to a ray source so that the cross section shape of a ray bundle passing through the scanning collimation hole is kept unchanged. In the scheme, the rotary shielding body needs to accurately process spiral line gaps, and also needs to consider the problems of providing enough ray shielding capacity, mechanism weight and rotational inertia, so that the rotary shielding body is difficult to realize on the basis of the existing processing technology.

There is also another idea of generating flying spots by using a radiation source that is capable of multiple radiation beams (distributed radiation source). The ray source is provided with a plurality of emergent target points, and the target points can be sequentially and independently emitted out through a control circuit. The collimation piece is arranged at the beam outlet of the ray source, so that each target point is provided with a corresponding collimation hole to constrain the rays into a pen beam. The control circuit makes the target points sequentially output beams, and the scanning flying spot similar to the scanning flying spot can be realized. In the scheme, the number of target points of a ray source is high, the number of points contained in one row of scanning lines is the required number of target points, for a radiation imaging image, the number of points scanned in one row is at least more than one hundred, if the image quality is required to be higher, the number of the required points scanned in one row is more, the number of the required emergent target points is more, and the whole set of device is high in cost.

Disclosure of Invention

The invention aims to provide a ray emitting device and an imaging system, which can modulate rays to form a uniform flying spot beam.

Another object of the present invention is to provide a radiation emitting apparatus and an imaging system, by which flying spots moving linearly at a continuous uniform speed can be formed.

According to an aspect of the present invention, there is provided a radiation emitting apparatus including: a rotating body having an axial direction, the axial direction being parallel to the predetermined direction; a radiation source capable of emitting radiation at a plurality of locations in the predetermined direction; and a collimator that enables the radiation emitted from the radiation source to form a fan-shaped beam at a plurality of positions in the predetermined direction, wherein the rotating body has a pencil beam forming portion arranged over an axial length of the rotating body corresponding to the plurality of positions, the fan-shaped beam forming portion forming a pencil beam by the pencil beam forming portion when the rotating body rotates about the rotation axis.

According to an aspect of the invention, the pencil forming portion is a plurality of discrete holes formed through the rotator.

According to an aspect of the invention, the rotating body is a barrel, and the pencil lead forming portion is a slit formed through a barrel wall of the barrel.

According to an aspect of the invention, the collimator comprises a linear slit arranged along the predetermined direction, through which slit the radiation emitted by the radiation source is substantially shaped as a fan beam.

According to an aspect of the invention, the radiation source comprises a plurality of target points arranged in a predetermined direction. For example, a plurality of target points of the radiation source are arranged at equal intervals.

According to an aspect of the invention, the collimator has a plate-like shape and adjoins the source of radiation.

According to an aspect of the present invention, the pencil bundles are sequentially formed in the predetermined direction by the pencil bundle forming section when the rotary body rotates.

According to an aspect of the invention, the target points, the slits and the rotation axis of the rotating body are substantially in the same plane.

According to an aspect of the present invention, the rotating body is made of a material capable of shielding rays.

According to an aspect of the invention, the collimating element is made of a material capable of shielding radiation.

According to an aspect of the present invention, there is provided an imaging system comprising: the above-mentioned radiation emitting device; and a scattering detector for receiving scattered rays scattered on the inspected object by the rays emitted by the ray emitting device.

The ray emission device can realize the uniform flying spot scanning of the target object, can conveniently realize the uniform sampling of the target object, and ensures that the obtained scanning image has no longitudinal compression deformation.

The direction of angular momentum of a rotating body, such as a rotating shield, is not changed while rotating the ray scanning fan, and thus the second dimension can be easily scanned by rotating the ray scanning fan without overcoming the moment of inertia of the rotating body. And the modulation device can be completed by matching with a mechanical interface on the X-ray machine in mass production, has compact structure, does not need to redesign the shielding body of the X-ray machine light tube, and saves the cost.

Because the multi-target distributed X-ray source is used, the emergent rays of the adjacent target points can be selected when different positions of an object are scanned, so that the side beam emergent fan angle of the target points can be reduced as much as possible, the larger the emergent fan angle is, the smaller the dose of the side beam is compared with that of the main beam, and the difference between the dose of the main beam and the dose of the main beam of the target points and the difference between the dose of the main beam and the image signal to noise ratio brought by the dose of. The source may be a distributed X-ray source, or may be a simple superposition of conventional single-target sources, for example, where multiple single-target sources are arranged in a straight line.

The scanning device can be completed by matching a mechanical interface on a mass-produced X-ray source without redesigning a shielding body of the X-ray machine bulb tube.

Drawings

FIG. 1 is a schematic view of a radiation source and a collimating element assembled together according to an embodiment of the present invention;

FIGS. 2a and 2b are schematic views of a radiation emitting apparatus according to an embodiment of the present invention;

FIG. 3a is a schematic view of a single target radiation source; and

figure 3b is a schematic view of a multi-target radiation source.

Detailed Description

The invention is further described with reference to the following drawings and detailed description.

As shown in fig. 2a and 2b, the imaging system 100 according to the present invention comprises: a radiation emitting device 30; a detector for receiving scattered rays scattered on the inspected object by the rays emitted by the ray emitting device 30; and a control part 40, wherein the control part 40 can rotate the rotating body 31 and control the corresponding emission target point 101 of the radiation source 33 to emit X-rays according to the rotating position of the rotating body 31.

As shown in fig. 1, 2a, and 2b, a radiation emitting apparatus 30 according to a real-time example of the present invention includes: a rotating body 31, the rotating body 31 having an axial direction, the axial direction being parallel to the predetermined direction; a radiation source 33, the radiation source 33 being capable of emitting radiation at a plurality of positions in the predetermined direction, the radiation source 33 being disposed in the vicinity of the rotating body 31; and a collimator 35, wherein the collimator 35 enables the radiation emitted from the radiation source 33 to form fan-shaped beams 111 at a plurality of positions in the predetermined direction. The rotating body 31 has a pencil beam forming portion 301 arranged over an axial length of the rotating body corresponding to the plurality of positions, and the fan-shaped ray beam 111 forms a pencil beam by the pencil beam forming portion 301 when the rotating body 31 is rotated about the rotation axis. When the rotating body 31 rotates, pencil bundles can be sequentially formed in the predetermined direction by the pencil bundle forming part 301. Preferably, collimating element 35 is closer to source 33 than rotating body 31.

As shown in fig. 1, 2a and 2b, the source of radiation 33 may be any suitable existing distributed source of radiation. For example, the radiation source 33 may comprise a plurality of target points 101 arranged in a predetermined direction. Multiple target points 101 may be individually controllable. Furthermore, the source of radiation 33 may be an X-ray source. Each target point 101 has the ability to emit radiation independently and individually in a specific sequence controlled by external control signals. The target points 101 may be in the same plane as the rotation axis of the rotating body 31. Furthermore, the number of targets is not limited.

In particular, the number of distributed X-ray sources used by the apparatus of the present invention to target is not strictly limited in principle or production process. Within a typical scan length of 1 meter, less than 2 targets are distributed, and more than 2 targets are distributed (for example, 1000 targets) within the limit (sub-millimeter level of target spacing) of the prior art production process, and no problem exists; in particular, when the number of target points is only 1, the conventional single-target X-ray source is used. Preferably, the device of the invention uses a distributed X-ray source with the number of target points within 10, so that the advantages and the control cost of the device can be better exerted.

As shown in fig. 1, 2a, 2b, the collimating element 35 may be a fixed shielding plate. The stationary shield is stationary with respect to the source, and the collimating element 35 or the stationary shield is made of a material that shields X-rays, such as lead, tungsten, copper, steel, lead tetraoxide, preferably lead. The collimator 35 includes a linear slit 351 provided along the predetermined direction, and the radiation emitted from the radiation source 33 is substantially shaped into a fan beam by the slit 351. The collimating element 35 may have a plate-like shape and adjoin said source of radiation 33.

As shown in fig. 2a and 2b, the rotating body 31 may be a rotating shield, and the rotating shield may be a solid cylinder and a hollow cylinder, preferably a hollow cylinder. The rotating shield may be rotatable about a rotation axis, which may be a central axis of the rotating shield. The fan beam is formed substantially in the same plane as the axis of rotation of the rotating body. The rotation axis of the rotating body 31, the linear slit 351 of the collimator 35 and the target point 101 of the X-ray source 33 may be located in the same plane. The rotating body 31 or the rotating shield is made of a material capable of shielding X-rays, and may be a single material structure (e.g., lead, tungsten, copper, steel, lead tetraoxide) or a combination of multiple material structures, preferably a single material structure. A typical combination of materials is: the hollow cylinder is formed by sleeving three cylinders, wherein the outermost cylinder and the innermost cylinder are made of materials with certain rigidity and hardness, such as aluminum or steel, and have a fixing function; the middle cylinder is made of typical ray shielding materials such as lead, lead-antimony alloy, tungsten and the like, and plays a role in shielding rays.

As shown in fig. 2a, 2b, the pencil-forming portion 301 is a plurality of discrete holes formed through the rotating body 31, or the rotating body 31 is a barrel, and the pencil-forming portion 301 is a slit 301 formed through a barrel wall of the barrel.

As shown in fig. 2a and 2b, the pencil-shaping portion 301 as the ray-incident region and the pencil-shaping portion 301 as the ray-emitting region on the rotating body 31 may be two continuous spiral grooves through which the rays can pass, or may be discrete through holes arranged along a spiral line, preferably a spiral groove. There is a one-to-one correspondence between the pencil beam forming part 301 as the ray incidence area and the pencil beam forming part 301 as the ray exit area, and any point of the pencil beam forming part 301 as the ray incidence area can only be communicated with one point of the pencil beam forming part 301 as the ray exit area, and together form a collimation hole which has a specific direction and can pass the ray, and the shape of the collimation hole can be round, square, diamond, ellipse, etc., preferably square.

As shown in fig. 1, 2a, and 2b, the radiation emitted from the radiation source 33 is collimated by the linear slit 351 of the collimator 35 to become the fan beam 111. All fan beam rays 111 are in the same plane.

As shown in fig. 2a and 2b, at any rotation position of the rotating body 31, the pencil beam shaping part 301 as a ray incidence region and the pencil beam shaping part 301 as a ray exit region on the rotating body 31 constitute a ray collimating hole 121 (see fig. 2a) with a specific spatial direction. According to the rotation position of the rotating body 31, the control part 40 controls the emitting lines of the corresponding target points 101 of the radiation source 33, the fan-beam radiation 111 collimated by the slit 351 of the collimating element 35 can pass through to form the pencil beam 131, the emitting lines of the other target points 101 of the radiation source 33 are controlled by the control part 40 after the rotating body 31 rotates for a certain angle, the pencil beam is formed through the other ray collimating hole, the operation is repeated, and finally, the emitting lines of the target points 101 of the radiation source 33 are controlled by the control part 40 after the rotating body 31 rotates for a certain angle, and the pencil beam 132 is formed through the ray collimating hole 130 (see fig. 2 b). With the uniform rotation of the rotating body 31, the pencil beam forming part 301 as the ray incident region and the pencil beam forming part 301 as the ray emitting region sequentially form the ray collimating holes with different spatial orientations, and the position of the passing ray pencil beam on the object 5 moves at a uniform speed along the direction parallel to the linear slit 351 on the collimator 35.

The linear slit 351 of the collimator 35, the pencil beam forming portion 301 as the ray incident region and the pencil beam forming portion 301 as the ray emitting region of the rotating body 31, and the scanning collimating hole are continuously formed, and the scanning collimating hole moves at a constant speed in the direction of the linear slit 351.

As shown in fig. 2a and 2b, the control unit 40 drives the rotating body 31 to rotate, and at the same time, obtains the angular position information of the rotating body 31, and controls the emission of the corresponding target point 101 of the radiation source 33 according to a certain rule. After the rays emitted from the ray source 33 are collimated by the collimating member 35, only the part that can pass through the ray collimating hole formed by the pencil beam forming part 301 as the ray incident region and the pencil beam forming part 301 as the ray emergent region on the rotating body 31 can become the emergent rays finally used for scanning, and the rest parts are shielded by shielding. The control unit 40 drives the rotating body 31 to rotate at a constant speed, so that the emergent rays for scanning move at a constant speed along a direction parallel to the linear slit 351 on the collimating element 35, thereby realizing the constant-speed scanning of the target object.

As described above, the ray emission device of the invention can realize uniform flying spot scanning of the target object, can conveniently realize uniform sampling of the target object, and enables the obtained scanning image to have no longitudinal compression deformation.

The direction of angular momentum of a rotating body, such as a rotating shield, is not changed while rotating the ray scanning fan, and thus the second dimension can be easily scanned by rotating the ray scanning fan without overcoming the moment of inertia of the rotating body. And the modulation device can be completed by matching with a mechanical interface on the X-ray machine in mass production, has compact structure, does not need to redesign the shielding body of the X-ray machine light tube, and saves the cost.

Because a multi-target distributed X-ray source or a combination of a plurality of single-target ray sources is used, the emergent rays of adjacent targets can be selected when different positions of an object are scanned, so that the side beam emergent fan angle of the target can be reduced as much as possible, the larger the emergent fan angle is, the smaller the dose of the side beam is compared with that of the main beam, and the difference between the dose of the side beam and the dose of the main beam of the target and the difference between the dose of the main beam and the image signal to noise ratio caused by the side beam is effectively.

As shown in FIG. 3a, for a single target ray source with a 90 degree exit angle, the dose ratio of the side beam 113 to the main beam 115 is only 1: 2. Instead of the single target source shown in FIG. 3a, a 5-target source as shown in FIG. 3b is used, the exit beam angle is reduced to 11.3 degrees, and the dose ratio of the side beam 113 to the main beam 115 is greatly improved to 1: 1.04. Meanwhile, due to the reduction of the exit fan angle of the side beam 113 of the target point, the inclination of two spiral line grooves of a rotator such as a rotary shielding body is reduced, and the production process is easier to realize compared with the production process of forming a line groove with a large inclination on a cylinder. As shown in fig. 3b, all fan beam beams 111 are in the same plane, while adjacent beams 111 are abutting to ensure that there are no missing scans or overlaps in the vertical scan direction.

The scanning device can be completed by matching a mechanical interface on a mass-produced X-ray source without redesigning a shielding body of the X-ray machine bulb tube.

Claims (13)

1. A radiation emitting device comprising:

a rotating body having an axial direction, the axial direction being parallel to the predetermined direction;

a radiation source capable of emitting radiation at a plurality of locations in the predetermined direction; and

a collimating element enabling the radiation emitted by the radiation source to form a fan-shaped beam at a plurality of positions in said predetermined direction,

wherein the rotating body has a pencil beam forming portion arranged over an axial length of the rotating body corresponding to the plurality of positions, the fan-shaped ray beam forming pencil beam by the pencil beam forming portion when the rotating body rotates about the rotation axis.

2. A radiation emitting device according to claim 1, wherein said pencil beam forming portion is a plurality of discrete holes formed through said body of revolution.

3. A radiation emitting device according to claim 1, wherein said rotational body is a barrel, and said pencil forming portion is a slit formed through a barrel wall of said barrel.

4. A radiation emitting device according to claim 1, wherein said collimator comprises a linear slit arranged along said predetermined direction, through which slit the radiation emitted from the radiation source is substantially shaped as a fan beam.

5. A radiation emitting apparatus according to claim 4, wherein

The radiation source comprises a plurality of target points arranged along a predetermined direction.

6. A radiation emitting apparatus according to claim 4, wherein

The collimating element has a plate-like shape and adjoins the radiation source.

7. A radiation emitting device according to claim 1, wherein

When the rotating body rotates, pencil bundles are sequentially formed in the predetermined direction by the pencil bundle forming portion.

8. A radiation emitting apparatus according to claim 5, wherein

The target points, the gap and the rotation axis of the rotating body are substantially in the same plane.

9. A radiation emitting apparatus according to claim 5, wherein

A plurality of target points of the ray source are arranged at equal intervals.

10. A radiation emitting device according to claim 1, wherein

All fan-shaped ray beams are in the same plane, and adjacent fan-shaped ray beams are mutually connected to ensure that no scanning omission place exists in the scanning direction.

11. A radiation emitting device according to claim 1, wherein

The rotating body is made of a material capable of shielding rays.

12. A radiation emitting device according to claim 1, wherein

The collimating element is made of a material capable of shielding radiation.

13. An imaging system, comprising:

a radiation emitting device according to claim 1; and

and the detector is used for receiving scattered rays scattered on the inspected object by the rays emitted by the ray emitting device.