CN111728628A

CN111728628A - Axial performance testing mold body for CT spiral scanning multi-plane reconstruction image

Info

Publication number: CN111728628A
Application number: CN202010579127.9A
Authority: CN
Inventors: 杜国生; 侯士国
Original assignee: Nuclover Technology Co ltd
Current assignee: Nuclover Technology Co ltd
Priority date: 2020-01-22
Filing date: 2020-06-23
Publication date: 2020-10-02

Abstract

The invention relates to a CT scanning reconstructed image axial performance testing die body, which is an organic glass cube or cuboid, wherein tungsten bead strings and tungsten wires for measuring the spatial resolution of a CT spiral scanning reconstructed image are respectively arranged in the body along three axial directions of X, Y, Z, 1-5 metal wires for measuring the layer thickness deviation of the CT spiral scanning reconstructed image are respectively arranged on six surfaces of the body, the metal wires are obliquely arranged on the surfaces, are equidistantly, parallelly and centrosymmetrically arranged, the highest end of the metal wire positioned below and the lowest end of the metal wire positioned above and adjacent to the highest end are positioned on the same horizontal line, and the included angle between the metal wire and the related surface is 18.4-45 degrees, the invention has the advantages of reasonable design, simple structure, firmness, reliability, convenient use and easy maintenance, the method can meet the requirement of axial performance test of CT spiral scanning multi-plane reconstructed images, and can also be used for measuring the performance of CT axial scanning reconstructed images.

Description

Axial performance testing mold body for CT spiral scanning multi-plane reconstruction image

Technical Field

The invention relates to the technical field of performance test of medical CT scanning reconstructed images, in particular to an axial performance test of CT spiral scanning reconstructed images, and specifically relates to a CT spiral scanning multi-plane reconstructed image axial performance test die body.

Background

At present, the medical CT scanning system of the medical institution equipment in China has completed the updating from single-row axial scanning CT to multi-row spiral scanning CT.

When CT scanning is performed in clinical diagnosis, spiral scanning is adopted for cardio-cerebrovascular radiography and chest and abdomen disease examination (namely, when X-rays are rotated and irradiated, an examinee lying on an examination table moves along with the bed, commonly called spiral scanning), and the CT scanning has the advantages of high scanning and imaging speed and has the defect that the image quality is not as good as that of the image quality of the commonly called axial scanning in which the examination table does not move during scanning.

During CT scanning, in order to accurately determine the focus morphology and avoid misdiagnosis and missed diagnosis, medical staff often needs to perform multi-axial plane reconstruction by adopting a spiral scanning technology after scanning and reconstructing a Z-axis tomography XY plane image (a cross-section image), so as to obtain a sagittal plane image (a Z-Y plane perpendicular to the ground and formed along the front and rear paths of the horizontal lying human body, namely the Z axis, is a sagittal plane) and a coronal plane image (an XZ plane parallel to the ground and formed along the left and right paths of the human body, namely the X axis, is a coronal plane) or three-dimensional reconstruction at any angle.

The performance quality management standard of the spiral scanning three-dimensional reconstruction image is not seen so far, and CT manufacturers refer to isotropy by themselves, but do not see detailed technical indexes and documentations thereof. In clinical radiodiagnosis of hospitals, the CT system axis scans the existing detection phantom to reconstruct the performance parameters of XY plane images and estimate the form and resolution of the focus three-dimensional image, which has the technical rigor defect, and is especially suitable for a wide-beam multi-row spiral CT scanning system.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a CT spiral scanning multi-plane reconstructed image axial performance testing die body which is reasonable in design, simple in structure, firm, reliable, convenient to use and easy to maintain, can be used for CT spiral scanning multi-plane reconstructed image axial performance testing, provides actual measurement data for reconstructed focus three-dimensional image performance evaluation, and can also be used for CT axis scanning reconstructed image performance measurement.

In order to achieve the above purposes, the technical scheme adopted by the invention is as follows:

the utility model provides a CT spiral scanning multiplanar reconstruction image axial capability test die body which characterized in that includes:

the body is an organic glass cube or cuboid with an upper surface, a lower surface, a left surface, a right surface, a front surface and a back surface,

the material of the body can also be other organic light solid materials, such as polycarbonate PC, polystyrene PS, nylon or bakelite,

the tungsten filament used for measuring the space resolution of CT spiral scanning multi-plane reconstructed images, namely the high-contrast resolution, is arranged in the body along the Z-axis direction, the diameter of the tungsten filament is 0.05-0.15 mm, a string of tungsten beads used for measuring the space resolution of the CT spiral scanning multi-plane reconstructed images, namely the high-contrast resolution, is arranged along the X, Y-axis direction, the tungsten bead string comprises a plurality of tungsten beads, the diameter of the tungsten beads is 0.2-0.3mm, the bead spacing is 5mm, and the three tungsten filaments and the tungsten bead string are not overlapped and crossed on the same plane.

The advantages of this design are: the data used by the spiral scanning three-dimensional reconstruction image is obtained from continuous scanning collection when an examination bed (Z-axis direction) moves, the dot image performances of tungsten filament segments and tungsten beads on an XY plane which is transverse to the Z axis are hardly different, and the difference of the MTF value of the space resolution measured and calculated by two dot images on the same plane is less than 0.5Lp/cm (within the range of actually measured 5-16 Lp/cm), and the two values are equal or different. While in the reconstruction of the XZ plane intersecting the X-axis YZ and the Y-axis XZ plane, the hardening artifact of the tungsten filament in a single direction is obvious, and the isotropy of the tungsten bead in the three-dimensional scanning is not influenced by the hardening artifact. The MTF value measured by the bead point image in the same XZ or YZ plane can be higher than 1.0Lp/cm than that measured by the tungsten filament section point image. Therefore, the tungsten filament is arranged in the Z-axis direction, and the tungsten bead strings (with the bead spacing of 5mm) are arranged in the X-axis direction and the Y-axis direction. The space resolution MTF value of each image with various scanning layer thicknesses can be continuously measured in the Z-axis direction and the tungsten filament length range, but the space resolution of the beaded image can only be measured if the space resolution MTF value cannot be measured in the X-axis or Y-axis direction.

Six of the body all are equipped with 1 ~ 5 tungsten filaments that are used for measuring diameter of CT helical scan many planes reconstruction image layer thickness deviation and are 0.1 ~ 0.3mm on the surface, the tungsten filament all sets up in the surface low left side height on the right side or high left side low right side slant, equidistance, parallel arrangement, and the highest end of the tungsten filament that is located the below, and the least significant end that is located the tungsten filament of top rather than adjacent are in same water flat line, and the contained angle that is used for measuring the oblique line of the above, below of the scanning layer thickness deviation of crossing Z axle and the preceding or back of body is α₁The included angle between the oblique lines on the front and back surfaces for measuring the thickness deviation of the scanning layer crossing the X-axis and the left or right surface of the body is α₂The oblique lines on the left and right sides for measuring the thickness deviation of the scanning layer intersecting the Y axis form an angle α with the upper or lower surface of the body₃Said angle α₁、α₂、α₃The angle of the angle is 18.4-45 degrees,

the tungsten wire on the surface of the body can also adopt a copper wire or a steel wire or a tin wire;

furthermore, the tungsten filaments on the six surfaces of the organic glass body are arranged in the grooves on the surface of the body, three tungsten filaments are respectively arranged on the upper surface and the lower surface of the organic glass body, and two tungsten filaments are respectively arranged on the left surface, the right surface, the front surface and the rear surface of the organic glass bodyThe diameter of the tungsten filament is 0.1mm, all the tungsten filaments are arranged symmetrically with the center of the surface, and the included angle α is formed₁、α₂、α₃Are all at 26.6 degrees;

further, the air conditioner is provided with a fan,

the body is provided with a first through hole along the X axial direction,

the body is provided with a second through hole along the Y-axis direction,

the body is provided with a third through hole along the Z-axis direction,

the tungsten filament and the tungsten bead string for measuring the image space resolution are respectively arranged on the central axis line position in the cylindrical supporting and protecting rod matched with the through hole;

furthermore, the body is a cuboid, the long edge of the body is along the Z-axis direction, and four edges of the body along the Z-axis direction are provided with plane or arc surface chamfers;

the test die body provided by the invention has the advantages of reasonable design, simple structure, firmness, reliability, convenience in use, easiness in maintenance and the like, has high test efficiency, can meet the requirement of axial performance test of CT spiral scanning multi-plane reconstructed images, and can also be used for measuring the performance of CT axial scanning reconstructed images.

The testing mold body has high testing efficiency, and all commercially available spiral CT scanning systems can reconstruct three plane images of XY, XZ and YZ by using data of the testing mold body through one-time spiral scanning; the thickness deviation (mm) and the spatial resolution MTF (Lp/mm) of the reconstructed image can be measured by using related software programmed by the existing image processing technology.

The software calculates and calculates the layer thickness deviation (mm) of the reconstructed image, namely, the length of the half-width of the corresponding metal wire image on the XY, XZ and YZ plane images obtained by analyzing and calculating the reconstruction of the tomography test mold body, namely, the accurate value of the scanning reconstructed layer thickness is calculated.

The software measures and calculates the image spatial resolution MTF (Lp/mm), namely the software analyzes and calculates a point image of a tungsten filament (for example, the diameter of 0.05mm and the total length of 50-200 mm) or a tungsten bead arranged in the three axial directions obtained by a tomography test phantom reconstruction plane, analyzes a two-dimensional line diffusion function of the point diffusion function in the prior art, calculates and gives a modulation transfer function curve (MTF), and marks the contrast on the curve, the corresponding spatial resolution value and the line pair/centimeter (Lp/cm).

For example, a known water model is connected in front of or behind the test phantom, and related software is programmed by using the existing image processing technology, so that the following properties of the spiral scanning water model reconstruction multi-plane image can be measured: CT values of water, image noise, uniformity, and Low Contrast Detectability (LCD).

Drawings

The invention has the following drawings:

FIG. 1 is a schematic diagram of a test phantom,

figure 2 is a schematic view of the top of a test mold body,

FIG. 3 is a schematic view of the underside of a test phantom,

FIG. 4 is a schematic left and right side view of the test mold body,

figure 5 is a schematic front view of a test mold body,

FIG. 6 is a schematic rear view of a test phantom,

FIGS. 7 to 11 are schematic diagrams showing the specific number of wires.

FIG. 12 is a schematic view of the layout of three tungsten filaments and tungsten bead strings

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 1-12, fig. 1 is a perspective view of the present invention, facing the rear face 6 of the mold body, and fig. 2-6 are views of the six-sided development of the present invention, based on the front face 5 of the mold body.

The invention relates to a model body for testing axial performance of CT spiral scanning multi-plane reconstruction images, which comprises:

the body 20 is a cube or a rectangular column (see fig. 1) having three pairs of surfaces, i.e., an upper surface 1, a lower surface 2, a left surface 3, a right surface 4, a front surface 5, and a rear surface 6, the body 20 is made of an organic light solid material, preferably an organic material having a density close to that of water, such as polycarbonate PC, high density polyethylene, polystyrene PS, organic glass (PMMA, also called acrylic), nylon, or bakelite, and the embodiment is made of organic glass.

The tungsten filament and the tungsten bead string for measuring the space resolution, namely the high contrast resolution of the CT spiral scanning multi-plane reconstruction image are arranged in the body along the direction of the X, Y, Z axis, and the following embodiments can be adopted (see fig. 12): the tungsten filament 10 is arranged along the Z-axis direction, a string of tungsten beads is respectively arranged along the X, Y-axis direction, the X-axis is a first tungsten bead string 13, the Y-axis is a second tungsten bead string 14, the bead spacing is 5mm, the three tungsten filaments and the tungsten bead strings (the tungsten filament 10, the first tungsten bead string 13 and the second tungsten bead string 14, the total three tungsten filaments and the tungsten bead strings are not overlapped and crossed on the same plane, the diameter of the tungsten filament is 0.05-0.15 mm, and the diameter of the tungsten bead is 0.2-0.3 mm. The three tungsten filaments and the two tungsten bead strings are not overlapped and contacted with each other, namely, no crossed contact point exists between the tungsten filament 10 and the two

tungsten bead strings

13 and 14 in space; when the scheme of arranging the supporting rods (supporting and protecting rods) is adopted, the non-overlapping means that the supporting rods of the three tungsten filament and tungsten bead strings do not have intersected cross contact points in space, and the aim is to avoid the overlapping of scanned images; fig. 12 shows an example of the layout of tungsten filament and tungsten bead string, and a supporting and protecting rod for fixing the tungsten filament and tungsten bead string is inserted into the

holes

7, 8 and 9 in fig. 1. The diameter of the tungsten wire is 0.05-0.15 mm, wherein the diameters of 0.05mm, 0.07mm, 0.1mm, 0.12mm and 0.15mm can be selected.

The tungsten filament 10 and the

tungsten bead strings

13 and 14 in the body 20 are respectively perpendicular to three pairs of surfaces of the mold body, as shown in fig. 12, the tungsten filament 10 in the Z-axis direction is perpendicular to the front (the supine head position of the patient, namely the CT frame position) and the rear (the foot position of the patient), the tungsten bead string 14 in the Y-axis direction is perpendicular to the upper surface and the lower surface, and the tungsten bead string 13 in the X-axis direction is perpendicular to the left surface and the right surface. The arrangement of the space positions of the tungsten filament and the tungsten bead string considers the uniformity of the reconstructed image and avoids the interference of hardening artifacts of X-ray scanning.

The six surfaces of the body 20 are provided with 1-5 metal wires 30 for measuring the layer thickness deviation of the CT spiral scanning reconstructed image, and the metal wires can be tungsten wires, copper wires, steel wires or tin wires. The number of the metal wires on each surface can be the same, for example, 2, 3, 4 or 5, the number of the metal wires on each surface can also be different, the material of the metal wires can be the same or different, and the metal wires can be selected according to the design of the ratio between the die body length and the image length of the metal wires and the thickness of the scanning layer, and particularly, refer to fig. 7 to 11. In the embodiment shown in fig. 2 to 6 (schematic diagrams of the development of six surfaces of the mold body), two metal wires are arranged on the front, rear, left and right four surfaces, and three metal wires are arranged on the upper and lower surfaces respectively; tungsten wire is used as the metal wire in this embodiment.

The wires 30 are all arranged obliquely on the surface, parallel to each other and equidistant.

One embodiment of the invention is: on the plan views of the upper part 1 and the

lower part

2, 3 metal wires are arranged for collecting the thickness information (spiral scanning and axial scanning) of the scanning reconstructed image layer of the cross section (XY plane), the metal wire 30 is obliquely arranged to be lower left and higher right, higher left and lower right, the highest end 31 of the metal wire positioned below and the lowest end 32 of the metal wire positioned above and adjacent to the metal wire are positioned on the same horizontal line, and the purpose of the arrangement is that: within the length of the phantom, continuous layer thickness information is acquired on each layer of image that is reconstructed by the wide-range helical scan (or axial scan), i.e., the projections of the wire 30 are not interrupted or overlapped during the multi-layer continuous scan reconstruction.

Two metal wires are arranged on the left plane view 3 and the right plane view 4 and are used for acquiring the thickness information of the coronal plane (XZ plane) scanning and reconstructing image layers.

Two metal wires are arranged on the front 5 and back 6 plane views and are used for acquiring the thickness information of the scanning and reconstruction image layer of the sagittal plane (YZ plane).

In the embodiment of fig. 1 to 6 of the present invention, the metal wire (tungsten wire) 30 is disposed in the groove 301 on the surface of the body 20, three tungsten wires are disposed on the upper surface 1 and the lower surface 2, and two tungsten wires are disposed on the left surface 3, the right surface 4, the front surface 5, and the rear surface 6. Because the partial volume effect of CT scanning imaging is also called volume effect, the image contrast of the metal wire with the same material and the same wire diameter in the image reconstructed by scanning different layer thicknesses in the same background material can be greatly different, the diameter of the tungsten wire is 0.1-0.3 mm, which is an experimental optimized value through various materials and wire diameters, wherein the diameters of 0.1mm, 0.2mm and 0.3mm can be selected.

The parallel wires (tungsten wires) may be offset on the die body surface (i.e. located near one side), but the preferred arrangement is: all tungsten filaments are symmetrically arranged with the center of the surface, so that the tungsten filaments are uniformly distributed, and the test positioning and data processing programming are convenient, and the method is shown in figures 1-6.

The oblique lines on the upper surface 1 and the lower surface 2 for measuring the thickness deviation of the scanning layer of the cross section (intersecting the Z axis) form an angle α with the front surface 5 or the rear surface 6 of the body 20₁The inclined lines on the front 5 and the back 6 for measuring the scanning layer thickness deviation of the sagittal plane (transverse X axis) form an included angle α with the left 3 or the right 4 of the body 20₂The inclined lines on the left surface 3 and the right surface 4 for measuring the scanning layer thickness deviation of the coronal plane (intersecting the Y axis) form an included angle α with the upper surface 1 or the lower surface 2 of the body 20₃Said angle α₁、α₂、α₃The angle of the angle is 18.4-45 degrees, and the included angle is α₁、α₂、α₃The angles of the metal wire scanning reconstruction images can be different from each other or the same, when the included angle is selected to be 45 degrees, the length of the metal wire scanning reconstruction image is equal to the scanning reconstruction layer thickness, when the included angle is selected to be 18.4 degrees, the length of the metal wire scanning reconstruction image is three times of the scanning reconstruction layer thickness (the projection relation is 1/tan α), the measurement accuracy of a thinner layer can be improved, but the difficulty of die body placement and alignment is also increased, and the included angle α is₁、α₂、α₃The optimal selection is 26.6 degrees, and the length of the half width of the metal wire scanning reconstruction image is twice of the thickness of the scanning reconstruction layer. This can form a range of products.

The tungsten filament and the tungsten bead string can be directly arranged in a die body, for example, the die body is manufactured into a whole when being formed. In order to facilitate the processing and manufacturing of the die body and the testing and use of the die body, the main body 20 is respectively provided with a through hole 7, a through hole 8 and a through hole 9 along three axial directions of X, Y, Z, the tungsten filament and the tungsten bead string are arranged on an axis position (not shown in the figure) of a cylindrical supporting and protecting rod which is made of the same material as the die body, and the size of the supporting and protecting rod is matched with that of the through holes, so that the manufacturing precision is ensured, and the die body is convenient to assemble and use.

The body 20 can be a cube or a cuboid (including 6 faces which are all rectangles, or front and back 2 faces which are squares, and upper, lower, left and right 4 faces which are rectangles), and specifically, independent mold bodies or multifunctional test mold bodies combined with other CT imaging performance test modules can be designed according to different needs by selecting different shapes, sizes and dimensions.

As an alternative embodiment, the die body side length may be 7 to 24cm, for example, cubic die bodies such as 7 × 7, 9 × 9, 11 × 11, 12 × 12, 15 × 15, 17 × 17, 20 × 20, 22 × 22, or 24 × 24cm are all optional embodiments; for a cuboid die body, the Z axial length of the cuboid die body can be 1.1, 1.3, 1.5, 1.7 or 2.0 times of the side length of the front side and the rear side correspondingly, and the cuboid test die body can be used in a head die or an abdomen die; test phantom bodies of 20, 22 or 24cm cubed sides may be used independently.

Specific placement of the wires 30 referring to fig. 7-11, the dashed lines are only used to indicate that "the highest end 31 of the lower wire 30 and the lowest end 32 of the adjacent upper wire 30 are in the same horizontal line".

FIG. 7 shows a wire assembly comprising 1 wire 30 at an included angle α_1、2、3Is 45 DEG, can be used for scanning test with the layer thickness of 10 mm;

FIG. 8 shows a configuration comprising 2 wires 30, angled at α_1、2、326.56 ° (approximately 26.6 °);

FIG. 9 shows a wire assembly comprising 3 wires 30 at an included angle α_1、2、318.4 deg., which can be used for scanning tests with a layer thickness of 5 mm.

The main body 20 of the present invention may be a cube or a rectangular parallelepiped, and the long side of the rectangular parallelepiped is along the Z-axis direction.

For use with other test mold bodies, the body 20 of the present invention may have planar chamfers or rounded chamfers along the Z-axis.

The test die body, the test using method and the data processing method can be carried out by referring to the prior art, and are not detailed.

Those not described in detail in this specification are within the skill of the art.

Attached:

brief application instruction of axial performance test die body of CT spiral scanning multi-plane reconstruction image

The test die body can be designed into an independent die body according to different requirements by selecting different shapes, sizes and dimensions or can be combined with other CT imaging performance test modules into a multifunctional test die body.

When the axial performance index test of CT spiral scanning reconstructed images is implemented, the die body is arranged at the end, close to the frame, of the scanning examination bed, the Z axis of the die body is parallel to the scanning central axis, the height of the bed is adjusted, and the central position of the die body is adjusted to the central axis of the system scanning under the indication of positioning light. Scanning the front and side positioning images one by one. On the system image display interface, the checking and correcting die bodies are placed correctly in place, namely the upper surface and the lower surface are horizontal, the left surface and the right surface are vertical, and the front surface and the rear surface are vertical.

Making a spiral scanning acquisition plan: setting standard kV and mA, scanning time of each circle, scanning range (length), thread pitch, layer thickness (the best thin layer thickness is selected during spiral acquisition), a reconstruction algorithm and the like. Designing a reconstruction layer thickness, automatically reconstructing Z, Y, X triaxial plane images by the system after clicking an axial reconstruction program of the system, sending the reconstructed images to an image workstation, and copying DICOM image data by using an optical drive.

The layer thickness deviation (mm) and the spatial resolution MTF (Lp/mm) of the reconstructed image can be measured and calculated by using related software programmed by the existing image processing technology. Layer thickness dimensional deviations can also be measured with the naked eye using the DICOM tour software "RadiAnt DICOM Viewer (64-bit) Medixant".

Claims

1. The utility model provides a CT spiral scanning multiplanar reconstruction image axial capability test die body which characterized in that includes:

the body (20) is a cube or cuboid with an upper surface (1), a lower surface (2), a left surface (3), a right surface (4), a front surface (5) and a rear surface (6), the material of the body (20) is organic light solid material comprising polycarbonate PC, polystyrene PS, organic glass, nylon or bakelite,

tungsten beads (13, 14) and tungsten filaments (10) for measuring the spatial resolution, namely the high-contrast resolution, of the CT spiral scanning reconstructed image are arranged in the body (20) along three axial directions of X, Y, Z, wherein a string of tungsten beads (13, 14) is arranged along the X, Y axial direction respectively, the diameter of each tungsten bead is 0.2-0.3mm, the bead spacing is 5mm, a tungsten filament (10) is arranged along the Z axial direction, the diameter of each tungsten filament is 0.05-0.15 mm, and the three tungsten filaments and the tungsten bead strings are not overlapped and crossed on the same plane;

six of body (20) all are equipped with 1 ~ 5 metal silk (30) that are used for measuring CT helical scan reconstruction image layer thickness deviation on the surface, metal silk (30) all are in the surperficial low left and right high or high left and right low slant setting of place, equidistance, parallel arrangement, and the most extreme (31) of the metal silk that is located the below, and rather than the least extreme (32) of the metal silk that is located the top adjacent, be in same water flat line for the contained angle that is α with preceding (5) or back (6) of body (20) the slash on (1), following (2) of measuring the scanning layer thickness deviation of crossing Z axle₁The included angle between the oblique lines on the front surface (5) and the back surface (6) and the left surface (3) or the right surface (4) of the body (20) is α for measuring the thickness deviation of the scanning layer crossing the X axis₂The included angle between the oblique lines on the left surface (3) and the right surface (4) and the upper surface (1) or the lower surface (2) of the body (20) is α for measuring the thickness deviation of the scanning layer intersecting the Y axis₃Said angle α₁、α₂、α₃The angle is 18.4-45 degrees, the diameter of the metal wire is 0.1-0.3 mm, and the metal wire is tungsten wire or copper wire or steel wire or tin wire.

2. The CT spiral scanning multiplanar reconstruction image axial performance testing die body as claimed in claim 1, wherein the body (20) is an organic glass body, the metal wires (30) arranged on six surfaces of the body are tungsten wires, the metal wires (30) are arranged in the grooves (301) on the surface of the body (20), the upper surface (1) and the lower surface (2) are respectively provided with three tungsten wires, the left surface (3), the right surface (4), the front surface (5) and the rear surface (6) are respectively provided with two tungsten wires, the diameter of each tungsten wire is selected to be 0.1mm, all the tungsten wires are symmetrically arranged with the center of the surface, and the included angle is α₁、α₂、α₃All at 26.6 degrees.

3. The axial performance test phantom of the CT helical scanning multi-plane reconstruction image of claim 1 or 2, wherein:

the body (20) is provided with a first through hole (7) along the X axial direction,

the body (20) is provided with a second through hole (8) along the Y-axis direction,

the body (20) is provided with a third through hole (9) along the Z-axis direction,

the tungsten beads (13, 14) and the tungsten filament (10) are respectively arranged in the center of the supporting and protecting rod matched with the through holes (7, 8, 9).

4. The axial performance test phantom of the CT helical scanning multi-plane reconstruction image of claim 1 or 2, wherein: the body (20) is a cuboid, the long edge of the body is along the Z-axis direction, and four edges of the body (20) along the Z-axis direction are provided with plane or arc surface chamfers.

5. The axial performance test phantom of CT helical scanning multi-planar reconstruction images as claimed in claim 3, wherein: the body (20) is a cuboid, the long edge of the body is along the Z-axis direction, and four edges of the body (20) along the Z-axis direction are provided with plane or arc surface chamfers.