JPH0558B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a phantom for a tomography device, and in particular, it is used to evaluate and correct characteristics in the Z-axis direction of a tomography device that scans using a spiral scan method or the like. The present invention relates to a phantom for tomography equipment.

[Prior Art] As a conventional phantom for a tomography device using a helical scan method such as a helical scan of this kind, for example, there is a
Volume 3, "Basic CT Research Report 9", pages 247 to 249, describes the evaluation and evaluation of the characteristics of tomographic devices by arbitrarily arranging lead beads or beads and scanning them. A phantom for a tomographic apparatus that performs correction is disclosed.

[Problems to be Solved by the Invention] A conventional phantom for a tomography device such as a spiral scan method has a method in which lead beads or beads are arranged arbitrarily,
Since this is scanned, if the position of the center axis of the lead ball or bead changes, it is possible to determine whether the cross-sectional diagnosis result is affected by the diameter of the lead or bead or by the Z-axis volume effect. It may not be possible.

In addition, when outputting diagnostic results as tomographic data values for each bit, it was necessary to clearly define boundaries, but when a phantom made of synthetic resin is placed in the atmosphere, the mass of the X-rays increases. Since there was no significant change in the absorption coefficient, the boundary line of the phantom could not be clearly imaged.

On the other hand, according to the patent publication, Utility Model Application No. 60-159357
There is an idea for publication in the issue.

The phantom of the invention is composed of a sealable water tank, a bubble collection chamber communicating with the water tank, and a test phantom housed in the water tank and removable. It consists of a plurality of supported measurement solution storage containers.

In this type of phantom, solutions of different concentrations or types are stored in a plurality of measurement solution storage containers, and the degree of freedom in selecting the radiation transmittance is provided.

However, even if the radiation transmittance in multiple measurement solution storage containers differs, there is no information factor that makes the boundaries of diagnostic results clear in a helical scan type tomography device, and the boundaries of the phantom are clearly imaged. I couldn't convert it.

Therefore, it is an object of the present invention to provide a phantom for a tomography device in which the characteristics of a helical scan type tomography device in the body axis, that is, the Z-axis direction, directly appear in the diagnostic results, and in which the characteristics of the tomography device can be evaluated. It is.

[Means for Solving the Problems] A phantom for a tomography device according to the invention of claim 1 includes a plurality of spheres arranged to be arranged in the body axis direction of the tomography device, and a built-in plurality of spheres, and The device includes a closed container having a substantially uniform wall thickness in a direction perpendicular to the length direction, and a liquid filled between the sphere and the closed container.

A phantom for a tomography device according to a second aspect of the present invention includes a pyramid, a closed container containing the pyramid and having a substantially uniform wall thickness around the vertical direction to the length direction thereof, and a closed container containing the pyramid and the pyramid. and a liquid filled between the container and the sealed container.

The phantom for a tomography device according to the invention of claim 3 includes a plurality of spheres and pyramids, and a sealed structure having a substantially uniform wall thickness around the vertical direction to the length direction of the phantom. The device includes a container, and a liquid filled between the plurality of spheres and pyramids and the closed container.

[Function] In the invention according to claim 1, a plurality of spheres arranged to be disposed in the body axis direction of the tomography device, a closed container containing the plurality of spheres and having a substantially uniform wall thickness, and a sealed container having a substantially uniform wall thickness, and the spheres The spheres are composed of a liquid filled between the body and the closed container, and the sphere centers can be placed on the same line, and there is no deviation of the sphere centers between the spheres, so continuous tomographic data of the spheres can be arranged on the same line in the body length direction. By changing the helical scan slice thickness, table movement speed, etc., and determining the tomographic data of the sphere where the center is located, it is possible to examine how a series of spheres can be visually resolved. The outline of the sphere is clarified by the difference in density between the liquid and the sphere, and circular tomographic data can always be obtained by continuous tomography of the sphere. With this, a cross section in the body axis direction can be reconstructed, and it can be used as an index of the detectable size of an ulcer or the like in the human body. Furthermore, the sealed container having a substantially uniform wall thickness does not cause disturbances in the tomographic data of the sphere due to discontinuities such as X-ray diffraction and X-ray absorption at specific locations.

The invention of claim 2, like the former, comprises a closed container with a built-in pyramid and a substantially uniform wall thickness, and a liquid filled between the pyramid and the closed container, and the liquid and the pyramid are separated. The outline of the pyramid can be clarified by the difference in density, and by changing the helical scan slice thickness, table movement speed, etc., and determining the tomographic data of the pyramid, it is possible to visually decompose the pyramid. You can examine whether you can do it.

In the invention of claim 3, like the former, a sphere and a pyramid, a closed container containing the sphere and pyramid and having a substantially uniform wall thickness, and a container filled between the pyramid and the closed container. It is made of liquid, and the outlines of the sphere and pyramid can be clarified by the difference in density between the liquid and the sphere and pyramid, and tomographic data for both can be obtained at the same time by tomography of the sphere and pyramid. The centers can be placed on the same line, and there is no misalignment of the centers of the spheres.

Continuous tomographic data of a sphere has its center located on the same line in the body length direction, and by changing the helical scan slice thickness, table movement speed, etc., and judging the tomographic data of the sphere, the continuous sphere can be visually visualized. By examining the tomographic data of the pyramid, it is possible to examine how the pyramid can be visually decomposed.

[Example] Examples of the present invention will be described below.

FIG. 1 is a perspective view, partially in section, of a phantom for a tomography device according to a first embodiment of the present invention. FIG. 2 is a sectional view taken along section line XX in FIG. 1.

In the figure, a sphere 1 is made of synthetic resin, and in particular, in this embodiment, it is a sphere made of synthetic resin such as acrylic. The closed container 2 is made of synthetic resin, and in particular, in this embodiment, it has a cylindrical shape with both end faces made of synthetic resin such as acrylic, houses the sphere 1, and has a uniform thickness. The support member 3 connects and supports the spherical body 1 with the closed container 2, and the spherical body 1 is arranged with its spherical center on the central axis of the closed container 12. In particular, the support member 3 is made of synthetic resin such as acrylic in this embodiment. Also, between the sphere 1 and the sealed container 2, the liquid 4 of this embodiment is
It is filled with water.

As described above, the phantom for a tomography apparatus of this embodiment includes one sphere 1, a sealed container 2 containing the sphere 1 and having a uniform wall thickness, and a sealed container 2 in which the sphere 1 is inserted between the sealed container 2 and the sealed container 2. It comprises a support member 3 for supporting, and a liquid 4 filled between the sphere 1 and the closed container 2.

The phantom for a tomography apparatus according to this embodiment is normally arranged with the length direction of the closed container 2 aligned with the body axis direction of the tomography apparatus, that is, the Z-axis direction. At this time, if the support member 3 is made of synthetic resin such as acrylic, the center of gravity moves toward the support member 3,
A stable position is reached when the support member 3 side is positioned downward.

When a test scan of the tomographic device is started in this state, the X-ray transmission conditions for one sphere 1 are 360 degrees perpendicular to its length.
Since the conditions are almost the same and the effect is only due to the support member 3, most of the tomographic data will be circular, making it possible to visually evaluate the characteristics of the tomographic device. Therefore, the characteristics of the tomographic device can be evaluated.

In particular, the movement of the tomography device in the Z-axis direction is 5 [mm/s]
Even with a tomography device that scans using a spiral scan method with a wide cutting interval of about 20 seconds at a speed of about 20 seconds, if the cut section is corrected to be circular, it can be cut at any position within a width of 10 mm. can do.

In addition, as a result, the tomographic data of the sphere 1 only needs to be circular, so even if the length direction of the sealed container 2 and the Z-axis direction of the tomography device do not match exactly, no error will occur. .

In this embodiment, the support member 3 is made of synthetic resin such as acrylic, and the position of the center of gravity allows the support member 3 to be in a stable state when it is positioned downward. In some cases, it may be made of synthetic resin or a material having the same density as the liquid 4.

In addition, the phantom for a tomography device of the above embodiment is
By making the airtight container 2 with a uniform wall thickness into a substantially spherical structure including a rugby ball shape, a substantially spherical airtight container 2 with a uniform wall thickness and a substantially spherical airtight container 2 with a built-in one or more spheres 1 having different diameters are formed. a support member 3 that supports the spherical body 1 between the container 2 and the spherical body 1;
A phantom for a tomographic apparatus may include a liquid 4 filled between an airtight container 2 and a closed container 2.
Since this type of phantom for a tomographic device has no directionality, it is easy to set up for the tomographic device. especially,
In this type of phantom for a tomography device, the support member 3 is made of a synthetic resin such as acrylic, and the outer surface of the support member 3 of the spherical closed container 2 is slightly flattened to improve stability and setting position accuracy. This can be a modification of the first embodiment.

FIG. 3 is a sectional view corresponding to FIG. 2 of the phantom for a tomography apparatus according to a second embodiment of the present invention. In the drawings, the same reference numerals and symbols as those in the conventional example indicate the same or corresponding parts as those in the conventional example.

In the figure, a sphere 1 is a sphere made of synthetic resin, and a sealed container 12 is made of synthetic resin. In particular, in this embodiment, it is a rectangular parallelepiped (hollow prismatic shape) having both end faces made of acrylic. 1 and is integrally formed with a hexahedron 12b of uniform thickness, and the thickness on the diagonal of the side 12a is different from that of the hexahedron 12b of uniform thickness. Therefore,
The rectangular parallelepiped shape (hollow prismatic shape) having both end faces has a substantially uniform thickness. That is, it is formed by joining six hexahedral plates 12b of uniform thickness. The support member 13 is made of synthetic resin, supports the spherical body 1 between it and the hermetic container 2, and arranges the spherical body 1 with its spherical center on the central axis of the hermetic container 12. Further, water is filled between the sphere 1 and the closed container 12 as the liquid 4 of this embodiment.

As described above, the phantom for a tomography apparatus of this embodiment has one sphere 1, a rectangular parallelepiped sealed container 12 containing the sphere 1 and having a substantially uniform wall thickness, and the sealed container 2. The device includes a support member 13 that supports the spherical body 1, and a liquid 4 filled between the spherical body 1 and a closed container 12.

Since the lower surface of the closed container 12 of the tomography device phantom of this embodiment is flat, it is easy to arrange it at a predetermined position and is stable.

When a test scan of the tomography device is started in the installed state, the X-ray transmission conditions for one sphere 1 are approximately the same 360 degrees around the vertical direction to the length direction of the closed container 2, and it is a nearly rectangular parallelepiped. side 1 of shape
When irradiating from the direction 2a, strictly speaking, 6
Due to the difference in thickness between the facepiece 12b and the side 12a, the tomographic data will differ due to slight discontinuities such as X-ray diffraction and X-ray absorption, but the tomographic data will be approximately circular. , it is possible to visually evaluate the characteristics of the tomographic device, and
The characteristics of the tomographic device can be evaluated using the tomographic data.

In addition, as in the first embodiment, since it is sufficient that the tomographic data is approximately circular as a result, even if the length direction of the closed container 2 and the Z-axis direction of the tomography device do not exactly match, Therefore, no errors occur.

FIG. 4 is a perspective view, partially in section, of a phantom for a tomography device according to a third embodiment of the present invention. In addition,
In the drawings, the same reference numerals and symbols as in the conventional example indicate the same or corresponding parts as those in the conventional example.

In the figure, the pyramid 21 is made of synthetic resin,
In particular, in this embodiment, it is a square pyramid formed from acrylic. The airtight container 22 is made of synthetic resin, and in this embodiment has a substantially rectangular parallelepiped shape (hollow prismatic shape) with both end faces made of acrylic.
It has a built-in wall and is formed with a uniform thickness. That is, a hexahedron 22b with a uniform thickness is integrally molded, and its corner portions 2
2a has a smooth curved surface and has the same thickness as the hexahedron 22b. Further, the support member 23 is made of synthetic resin, supports the pyramid 21 between it and the closed container 22, and arranges the pyramid 21 with its axis on the central axis of the closed container 12. There is. Water is filled between the pyramid 21 and the closed container 12 as the liquid 4 of this embodiment.

In this way, the phantom for a tomography apparatus according to the present embodiment includes a pyramid 21 whose cross section changes in the body axis direction, and a pyramid 21 that is arranged in the body axis (Z-axis) direction of the tomography apparatus. A sealed container 12 that is built-in and has a substantially uniform wall thickness around the vertical direction with respect to its length, the pyramid 21 and the sealed container 1.
2 and a liquid 4 filled between them.

Therefore, the outline of the pyramid 21 can be clarified by the difference in density between the liquid 4 and the pyramid 21, and the tomographic data of the pyramid 21 can be determined by changing the slice thickness of the helical scan, the table movement speed, etc. By doing so, it is possible to examine how the pyramid 21 can be visually disassembled.

In particular, by determining the change in the transmission coefficient of X-rays to the pyramid 21, that is, the CT value, an index of resolution can be obtained.

For example, by comparing the amplitude of the maximum value and the minimum value with respect to the maximum value of the CT value and the reference value (air), it is found that the amplitude of the maximum value and the minimum value/the amplitude of the maximum value and the reference value is close to "1". The higher the resolution, the better the resolution.

As a result, good resolution means that unevenness can be expressed faithfully, and the phantom for a tomographic apparatus of this embodiment can be used as an indicator of this.

In the phantom for a tomography apparatus of this embodiment, since the lower surface of the closed container 22 is flat, it is easy to arrange it at a predetermined position and is stable.

When a test scan of the tomography device is started in the installed state, the X-ray transmission conditions for one pyramid 21 are approximately the same 360 degrees around the vertical direction with respect to the length direction of the closed container 22, and the second As in the example, disturbances in the tomographic data due to discontinuities such as X-ray diffraction and X-ray absorption are less likely to occur on the side 12a, and the tomographic data becomes approximately rectangular, allowing for visual evaluation of the characteristics of the tomographic device. Furthermore, the characteristics of the tomographic apparatus can be evaluated based on the tomographic data.

In the above embodiment, it is mainly assumed that there is only one sphere 1 and one pyramid 21, but as described in the modification of the first embodiment, it is also possible to use a plurality of them. In an embodiment in which a plurality of spheres 1 and/or pyramids 21 of this type are accommodated, the spheres 1 and/or pyramids 21 may have the same shape or may have different sizes. Preferably, in either embodiment, the axes thereof are arranged in a straight line. Further, in the pyramid 21, the slopes of two or four sides may be different.

FIG. 5 is a sectional view of a phantom for a tomography device according to a fourth embodiment of the present invention. FIG. 6 is a sectional view taken along section line YY in FIG. 5.

In the figure, a sphere 1 is made of synthetic resin, and in particular, in this embodiment, it is a sphere made of acrylic. The closed container 2 is made of synthetic resin, and in particular, in this embodiment, it has a cylindrical shape with both end faces made of acrylic, houses the sphere 1, and has a uniform wall thickness. The support member 3 supports the spherical body 1 between it and the closed container 2, and arranges the spherical body 1 with its spherical center on the central axis of the closed container 12. In particular, the support member 3 is made of synthetic resin such as acrylic in this embodiment. Moreover, between the sphere 1 and the sealed container 2,
Water is filled as the liquid 4 in this embodiment.

As described above, the phantom for a tomography apparatus of this embodiment includes one sphere 1, a sealed container 2 containing the sphere 1 and having a uniform wall thickness, and a sealed container 2 in which the sphere 1 is inserted between the sealed container 2 and the sealed container 2. It comprises a support member 3 for supporting, and a liquid 4 filled between the sphere 1 and the closed container 2. In the drawings, the same reference numerals and symbols as those in the conventional example indicate the same or corresponding parts as those in the conventional example.

In the figure, spheres 31A and 31B are made of synthetic resin, and in this embodiment they are made of acrylic. The sphere 31A is set to have a smaller diameter than the sphere 31B, and the sphere 31A is set to have a smaller diameter than the sphere 31B.
1A and the sphere 31B are arranged so that their centers are on the same straight line. In addition, the pyramid 41A
The pyramid 41B is made of synthetic resin, and in this embodiment is a truncated square pyramid made of acrylic, and the pyramid 41A and the pyramid 41B have different inclination angles. The pyramid 41A is placed above the sphere 31A with a gap therebetween. Further, the pyramid 41B is placed on the sphere 31B with a gap therebetween.

The closed container 22 is made of synthetic resin, and in this embodiment has a substantially rectangular parallelepiped shape (hollow prismatic shape) with both end faces made of acrylic, and contains the spheres 31A and 31B, the pyramid 41A and the pyramid 41B, It is integrally molded with a uniform thickness, and its corner portion 22a has a smoothly curved surface, and has the same thickness as the hexahedron 22b. Water is filled as the liquid 4 in this embodiment between the spheres 31A and 31B, the pyramids 41A and 41B, and the closed container 22.

As described above, the phantom for a tomography apparatus of this embodiment has a plurality of rows of spheres 31A and a row of spheres 31B arranged in the body axis direction of the tomography apparatus, and a row of spheres 31A and a row of spheres 31B arranged in the direction of the body axis of the tomography apparatus. A sealed container 22 containing a row of spheres 31B and having a substantially uniform wall thickness around the vertical direction with respect to its length, and a space between the row of spheres 31A, the row of spheres 31B, and the closed container 22 are filled. It is equipped with a liquid 4 that is

Since the lower surface of the closed container 22 is flat, the phantom for a tomography apparatus according to this embodiment can be easily placed in a predetermined position and can be placed in a stable state.

When scanning of the tomographic apparatus is started in the installed state, the conditions for X-ray transmission to the spheres 31A and 31B, the pyramid 41A and the pyramid 41B become substantially the same 360 degrees, and the sphere 31A and the sphere 31
The tomographic data of B is circular, and the pyramid 41A
The tomographic data of the pyramid and the pyramid 41B are approximately rectangular, and the characteristics of the tomographic device can be visually evaluated, and the tomographic data can be used to evaluate the characteristics of the tomographic device.

A plurality of spheres 31A and a sphere 31B arranged in the body axis direction of the tomography device, an airtight container 22 containing the plurality of spheres 31A and the sphere 31B and having a substantially uniform thickness, and a sealed container 22 having a substantially uniform thickness; The liquid 4 is filled between the sphere 31B and the closed container 22, and the sphere centers can be arranged on the same line, and the sphere 3
Since there is no deviation of the spherical centers between the spherical bodies 1A and 31B, continuous tomographic data of the spherical bodies 31A and 31B have their spherical centers located on the same line in the body length direction.
The slice thickness of the helical scan, the table movement speed, etc. are changed, and the sphere 31A and the sphere 31B are
By determining the tomographic data of , it is possible to examine how the connected spheres 31A and 31B can be visually separated. And liquid 4 and sphere 3
Due to the difference in density between sphere 1A and sphere 31B, sphere 3
1A and the outline of the sphere 31B, and the sphere 31
Circular tomographic data can always be obtained by continuous tomography of A and sphere 31B. Thereby, the cross section in the body axis direction can be evaluated, and it can be used as an index of the detectable size of ulcers, etc. in the human body. In addition, the airtight container 22 has a substantially uniform wall thickness.
In this case, the tomographic data of the sphere is not disturbed by discontinuities such as X-ray diffraction and X-ray absorption at specific locations.

Incidentally, the spheres 1, 31A, and 31B of the phantom for a tomography apparatus in the above embodiment are solid synthetic resin spheres, but when carrying out the present invention, they may be hollow or have other densities in their center. It is also possible to fill the material with a multilayer structure. In any case, when carrying out the present invention, the precision of the spheres 1, 31A, 31B may be determined according to the characteristics of the tomographic apparatus in the Z-axis direction and the purpose of use, and any substantially spherical shape can be used.

Further, the closed containers 2, 12, and 22 of the phantom for a tomography apparatus of the above embodiments have a substantially uniform wall thickness, and have a cylindrical shape having both end faces, a rectangular parallelepiped shape (hollow prismatic shape) having both end faces, or, for example, A hexahedron 22b having a uniform thickness is integrally molded, and its corners 22a are smoothly curved, and the hexahedron 22b has a substantially rectangular parallelepiped shape (hollow prism shape) with the same thickness as the hexahedron 22b.

When carrying out the present invention, it is limited to a cylindrical shape having both end faces, a rectangular parallelepiped shape (hollow prismatic shape) having both end faces, or a substantially rectangular parallelepiped shape with chamfered corners (substantially hollow prismatic shape). It is sufficient that the container has a closed structure and has a substantially uniform wall thickness. Naturally, a sphere can also be used as a closed container when carrying out the present invention. However, when carrying out the present invention, it is desirable that the closed container has a form in which the transmission coefficient remains unchanged throughout 360 degrees around the container.

Although it has been explained that the supporting members 3, 13, and 23 of the phantom for a tomography device in the above embodiment are formed of a synthetic resin such as acrylic or a material having the same density as the synthetic resin or the liquid 4, when the present invention is implemented , pyramids 21, 41A, 41B, etc. may also be used. Basically, the supporting members 3, 13 are the spheres 1, 31
Since the axes of A and 31B are located at the central axes of the closed containers 2, 12, and 22, and the transmission conditions around the entire circumference of the closed container bodies 2, 12, and 22 can be made uniform, the specific If you sacrifice some surface accuracy,
Pyramids 21, 41A, 41B, spheres 1, 31A,
31B can be directly joined to the closed container 2, 12, 22.

Furthermore, although water is used as the liquid 4 filled in the closed container of the phantom for a tomography device in the above embodiment, water is used in this embodiment, but when implementing the present invention, pyramids 21, 41A, 41B, Sphere 1, 31A, 3
Any liquid may be used as long as it has a density different from that of 1B and the closed containers 2, 12, and 22.

Furthermore, although the pyramids 21, 41A, and 41B of the phantom for a tomography device in the above embodiments are solid synthetic resin spheres, when carrying out the present invention, they may be hollow or have other shapes in their center. It may be filled with a material having a density of In any case, when implementing the present invention, the pyramids 21, 41A, 4 may be
What is necessary is to determine the slope and accuracy of 1B.

Note that the sealed container constituting the phantom for a tomography device of the present invention has a sealed structure so as to be suitable for transportation, but when implementing this type of phantom for a tomography device, an open container can also be used. It is. Further, the liquid in this embodiment can also be replaced with a gas such as xenon gas.

And the supporting members 3, 13, 23 of the above embodiment
Although its existence is clearly depicted in the diagram,
In practice, thin wire-shaped materials are used so as not to interfere with the tomographic data. In particular, the sphere 31
In A and 31B, the spheres may be connected by a support member as a means of forming a gap between the spheres. Of course, it is also possible to directly connect the spheres.

[Effects of the Invention] As described above, the phantom for a tomography device according to the invention of claim 1 includes a plurality of spheres arranged to be arranged in the body axis direction of the tomography device, and a built-in plurality of spheres. It consists of an airtight container with a uniform wall thickness and a liquid filled between the sphere and the airtight container, and since the spherical centers can be placed on the same line and there is no deviation of the spherical center between the spheres, the continuity of the spheres is ensured. The tomographic data to be used is such that the centers of the spheres are located on the same line in the body length direction, and by changing the helical scan slice thickness, table movement speed, etc., and judging the tomographic data of the sphere, it is possible to visually determine how the connected spheres look. We can examine whether it can be decomposed into The outline of the sphere is clarified by the difference in density between the liquid and the sphere, and circular tomographic data can always be obtained by continuous tomography of the sphere. Thereby, the cross section in the body axis direction can be evaluated, and it can be used as an index of the detectable size of ulcers, etc. in the human body.

The phantom for a tomography device according to the invention of claim 2 is arranged in the body axis direction of the tomography device, and includes a pyramid body whose cross section changes in the body axis direction, and a pyramid body whose cross section changes in the body axis direction. The device includes a closed container having a substantially uniform wall thickness around the vertical direction, and a liquid filled between the pyramid and the closed container.

Therefore, the outline of the pyramid can be clarified due to the difference in density between the liquid and the pyramid, and the slice thickness of the helical scan, table movement speed, etc. can be changed,
By examining the tomographic data of the pyramid, it is possible to examine how the pyramid can be visually broken down. In particular, by determining changes in CT values for pyramids, an index of contrast can be determined and an index of resolution can be obtained.

The phantom for a tomographic apparatus according to the invention of claim 3 can simultaneously exhibit the effects of the invention of claim 1 and the invention of claim 2.

[Brief explanation of the drawing]

FIG. 1 is a perspective view with a partial cross section of a phantom for a tomography device according to a first embodiment of the present invention, and FIG.
FIG. 3 is a sectional view taken along cutting line X-X in the figure, and FIG.
FIG. 4 is a perspective view with a partial cross section of a phantom for a tomography device according to a third embodiment of the present invention, and FIG. 5 is a sectional view of a phantom for a tomography device according to a fourth embodiment of the present invention. , Figure 6 is the cutting line Y in Figure 5.
-Y is a sectional view. In the figure, 1, 31A, 31B... sphere, 2
1, 41A, 41B...Pyramid, 2, 12, 22
... Airtight container, 3, 13, 23 ... Support member, 4
...It's a liquid. Note that in the drawings, the same reference numerals and symbols indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A plurality of spheres arranged in the body axis direction of the tomography device, and a device containing the plurality of spheres and having a substantially uniform thickness around the vertical direction to the longitudinal direction thereof. A phantom for a tomographic apparatus, comprising: a sealed container formed therein; and a liquid filled between the sphere and the sealed container. 2. A pyramid whose cross section changes in the body axis direction of the tomography device so as to be disposed in the body axis direction, and a pyramid having a substantially uniform wall thickness around the vertical direction with respect to the length direction of the pyramid. A phantom for a tomographic apparatus, comprising: a sealed container; and a liquid filled between the pyramid and the sealed container. 3. A plurality of spheres arranged in the direction of the body axis of the tomography device and a pyramid whose cross section changes in the direction of the body axis; A phantom for a tomographic apparatus, comprising: a closed container having a substantially uniform wall thickness around a direction; and a liquid filled between the plurality of spheres and pyramids and the closed container.