| Project/Area Number |
17300170
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Medical systems
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
OGURI Yoshiyuki Tokyo Institute of Technology, Research Laboratory for Nuclear Reactors, Associate Professor (90160829)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Jun Tokyo Institute of Technology, Research Laboratory for Nuclear Reactors, Assistant Professor (90302984)
OGAWA Masao Komazawa University, Faculty of Health Sciences, Professor (60016863)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥15,760,000 (Direct Cost: ¥14,500,000、Indirect Cost: ¥1,260,000)
Fiscal Year 2007: ¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000)
Fiscal Year 2006: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2005: ¥6,300,000 (Direct Cost: ¥6,300,000)
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| Keywords | Angiography / Iodinated contrast medium / Exposure dose / K-absorption edge / Proton-induced X-ray emission / Characteristic X-ray / Micro ion beam / Glass micro capillary / 医療・福祉 / X線診断 / 静電加速器 / 画像分解能 / マイクロビーム / ガラスキャピラリー / 画像コントラスト / Energy subtraction法 / 医療用X線撮影 / 単色X線 / 吸収係数 / 陽子線 / コントラスト |
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| Research Abstract |
Characteristic-line radiation from heavy metal targets bombarded by MeV proton beams has been tested as an X-ray source for angiography based on iodinated contrast media. To utilize the strong absorption by iodine (Z=53) at its K-absorption edge (33.2 keV), we used K-alpha line of La (lanthanum, Z=57) at 33.4 keV. As a reference, also K-alpha emission of Sn (tin, Z =50) at 25.2 keV was employed. Metallic plates of La and Sn were irradiated by 7-MeV protons to produce these X-rays. Dual-energy K-edge subtraction method was tested using Lucite phantoms which contain aqueous solutions of potassium iodide. Also Calcium compound was stuffed in these phantoms to simulate bones. The transmission images of the phantoms were recorded on imaging plates. We found that the contrast of images of iodide solutions taken with La X-rays was higher than that with Sn X-rays. Also the energy subtraction procedure was successfully applied to reduce the graphical noise due to the bones and inhomogeneity of the soft tissue. However, for actual clinical use, the X-ray intensity must be increased by several orders of magnitude.
To increase spatial resolution of images, we constructed a compact proton micro-beam system using a tapered glass capillary tube with a tip diameter on the order of 10 microns. The transport efficiency of 2-3-MeV protons through the capillary was examined as a function of the capillary tilt angle and the tip diameter. We obtained transport efficiencies of approximately three times larger than would be expected from the geometrical shape of the capillary. A metallic thin foil was irradiated with the micro beam and quasi-monochromatic X-rays were produced. We demonstrated magnification radiography of a small object to show that a spatial resolution on the order of 10 microns was achievable in our system.
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