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Phantom and phantom assembly

外国特許コード F090002144
整理番号 F090002144
掲載日 2009年12月11日
出願国 アメリカ合衆国
出願番号 94869004
公報番号 20050141672
公報番号 7510325
出願日 平成16年9月24日(2004.9.24)
公報発行日 平成17年6月30日(2005.6.30)
公報発行日 平成21年3月31日(2009.3.31)
優先権データ
  • 特願2003-427312 (2003.12.24) JP
発明の名称 (英語) Phantom and phantom assembly
発明の概要(英語) A phantom assembly includes a plurality of cylindrical shaped phantoms connectable to each other and/or a plurality of column-shaped phantoms connectable to each other with fitting portions.
An x-ray radiation measuring device for measuring an x-ray radiation from an x-ray CT device is inserted in a through-hole of the phantom.
従来技術、競合技術の概要(英語) BACKGROUND OF THE INVENTION
1.
Field of the Invention
The present invention relates to a phantom and a phantom assembly (phantom unit) used as a dummy for a human body in assessing CT dosage of x-ray radiation, and is based on Japanese Patent Application No. 2003-427312, filed on Dec. 12, 2003, the disclosure of which is incorporated herein by reference.
2. Description of Related Arts
In a conventional assessment of CT dose, phantoms according to IEC (International Electrotechnical Commission) have been used (For example, see International Electrotechnical Commission, "Evaluation and routine testing in medical imaging departments constancy tests-x-ray equipment for computed tomography," pub.
IEC, 1223-2-6 (1994); T. B. Shope, R. M. Gane, and G. C. Johnson, "A method for describing the doses delivered by transmission x-ray computed tomography," Med.
Phys. 8, 448-495 (1981); and W. Leitz, B. Axelsson, and G. Szendro, "Computed tomography does assessment-A practical Approach." Radiat. Prot. Dosim., 57, 377-380 (1995)).
In this case, for example, two phantoms, one for body portion, and another for head, are ready and each made of an acrylic resin and formed into a cylinder having a diameter of 320 mm and 160 mm, respectively, and a length of 150 mm.
Cavities of 10 mm diameter were located parallel to the central axis of the cylinders, and the centers of the holes were located at the cylinder center and also 10 mm below the cylinder surface at 90 degree intervals (detailed in IEC document), and evaluation of x-ray irradiated onto a human body has been made by inserting a device for measuring dose.
In the conventional assessment of CT dose as described above, if conical beam having a large beam width of x-ray, what is called, cone beam is assessed by utilizing the phantoms, the phantoms should be form in a shape where the length of the shaft direction is large to meet the shape of the cone beam.
In this case, weight and the size of the phantom are increased, inconvenient for carrying the phantom and for storing it.
As a result, only an x-ray having a narrow beam width can be assessed by the conventional phantom.
When an x-ray is irradiated on such a phantom, the x-ray induces scattered radiation within the phantom, which is scattered distributed at random.
Accordingly, when the assessment of the x-ray radiation (patient dose) including the scattered radiation will be made, the weight and the size of the phantom will be much more increased, leading to inconvenience in terms of portability and storage of the phantom. (For dose assessment for the cone-beam, although the weight of the phantom will be increased, the phantom length should be longer than the conventional one, because the scattered radiation is distributed wider than that in the narrow beam width.)
In order to overcome the inadequacy just mentioned, it can be considered that edges portion of phantoms are lined up in a face-to-face manner whereby the length of the phantoms in the shaft direction is set to be large as a whole.
However, lining up of the phantoms has problems that fixation of the phantoms is incomplete and that x-ray radiation is passed through from gaps between the edge portions of the phantoms and, thus, no accurate assessment can be made.
In order to make a long phantom from a practical point of view, we joined unit phantoms together to provide phantoms of the necessary length.
An object of the present invention is to provide a phantom and a phantom assembly which can easily be carried, in which the length of the phantom can be freely set to meet the shape of an x-ray beam, in which phantoms can be tightly connected, and which can assess CT dose of x-ray radiation in an accurate manner without passing the radial from phantoms.
By inserting acrylic sticks through these holes, the cylinders were more tightly fixed to each other.
Moreover, the connection portion of the phantoms was step-shaped so as not to allow direct passage of x-rays through any gaps.

特許請求の範囲(英語) [claim1]
1. An apparatus for outputting a dose measurement result, comprising: a phantom extending in a direction, the phantom comprising edge portions at both ends, in the direction, of the phantom;
a material for attenuating a radiation into the phantom;a fitting portion formed on at least one of the edge portions;a plurality of through-holes in the material extending in the direction between the edge portions inclusively, said plurality of through-holes extending to the fitting portion;
and
a dose detector in at least one of the through-holes and configured to measure a dose of the radiation through the material and to output the dose measurement result.
[claim2]
2. The apparatus according to claim 1, wherein the phantom comprises a cylindrical shape, and wherein one of the plurality of through-holes is located at a central portion thereof for housing the dose detector.
[claim3]
3. The apparatus according to claim 1, wherein the phantom comprises a sleeve-shape extending in the direction having a hollow portion therein extending in the direction for housing an external phantom.
[claim4]
4. The phantom according to claim 1, wherein the fitting portion fits in a corresponding fitting portion of an external phantom.
[claim5]
5. The phantom according to claim 1, wherein the plurality of through-holes extends continuously between the edge portions inclusively.
[claim6]
6. The phantom according to claim 1, wherein the phantom comprises a ring portion as the fitting portion and a body having a cylindrical circumferential surface, and whereinthe ring portion has a circumferential surface and a fitting space either therein in which the circumferential surface is continuously connected to the cylindrical circumferential surface or between the cylindrical circumferential surface and the circumferential surface.
[claim7]
7. A phantom assembly for outputting a dose measurement result, comprising: a plurality of phantoms, each phantom extending in a direction and comprising edge portions at both ends, in the direction, of the phantom, a material for attenuating a radiation into the phantom, a fitting portion formed on at least one of the edge portions, and a plurality of through-holes in the material extending in the direction between the edge portions inclusively, said plurality of through-holes extending to the fitting portion;
and
a dose detector in at least one of the through-holes and configured to measure a dose of the radiation through the material and to output the dose measurement result, wherein the phantoms are connected with each other to have contact therebetween at the fitting portions thereof.
[claim8]
8. A phantom assembly according to claim 7, further comprising: at least one stick inserted into at least one of the through-holes for embedding the at least one of the through-holes.
[claim9]
9. The phantom assembly according to claim 8, wherein the at least one stick is arranged across two or more phantoms.
[claim10]
10. The phantom assembly according to claim 7, wherein each phantom has a cylindrical shape, and wherein one of the through-holes is located at a central portion thereof for housing the dose detector.
[claim11]
11. A phantom assembly for outputting a dose measurement result, comprising: a plurality of first phantoms, each first phantom extending in a first direction and comprising edge portions at both ends, in the first direction, of the first phantom, a material for attenuating a radiation into the first phantom, a column shape, a first fitting portion on at least one of the edge portions of the first phantom, and a plurality of through-holes in the material extending in the first direction between the edge portions of each first phantom inclusively, wherein the first phantoms are connected with each other at the first fitting portions;
and
a plurality of second phantoms, each second phantom extending in a second direction and comprising edge portions at both ends, in the second direction, of the second phantom, the material for attenuating the radiation into the second phantom, a sleeve shape comprising a hollow portion therein at both ends, in the second direction, of the second phantom, a second fitting portion formed on at least one of the edge portions of the second phantom, and a plurality of through-holes in the material extending in the second direction between the edge portions of each second phantom inclusively, wherein the second phantoms are connected with each other at the second fitting portions and house the first phantoms;
and
a dose detector in at least one of the through-holes and configured to measure a dose of the radiation through the material and to output the dose measurement result.
[claim12]
12. The phantom assembly according to claim 11, wherein the one of the through-holes of each of the first phantoms is located at a central portion thereof for housing the dose detector in the hollow portions.
[claim13]
13. The phantom assembly according to claim 11, further comprising at least one stick for embedding at least one of the through-holes of the first and second phantoms.
[claim14]
14. The phantom assembly according to claim 13, wherein the stick is arranged across two or more of the first phantoms.
[claim15]
15. The phantom assembly according to claim 13, wherein the stick is arranged across two or more of the second phantoms.
  • 発明者/出願人(英語)
  • ENDO MASAHIRO
  • MORI SHINICHIRO
  • NATIONAL INSTITUTE OF RADIOLOGICAL SCIENCES
国際特許分類(IPC)
米国特許分類/主・副
  • 378/207
  • 250/252.1
  • 378/18
  • 378/204
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