1991 Fiscal Year Final Research Report Summary
K-edge Energy Subtraction Angiography System using Synchrotron Radiation
| Project/Area Number |
02670504
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Radiation science
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| Research Institution | Saitama Medical School |
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Principal Investigator |
NISHIMURA Katsuyuki Saitama Medical School, Dept. of Radiology, Associate Professor, 医学部, 助教授 (10129158)
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| Co-Investigator(Kenkyū-buntansha) |
HYODO Kazuyuki KEK, Photon Factory, Assistant, 放射光, 助手 (60201729)
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| Project Period (FY) |
1990 – 1991
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| Keywords | K-edge subtraction / SR angiography / Synchrotron Radiation / Coronary angiograhy / Energy subtraction |
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| Research Abstract |
[Purpose] To develop the technique for K-edge subtraction angiography with Synchrotron Radiation and to make clear the problem for practical use.
[Method] l. Relationships between factors which affect the image quality and the amount of energy shift was made clear. 2. The method to remove the effect of third harmonics on subtracted image was proposed and verified with use of phantom. 3. II and a couple of CCD camera installed compactly. 4. Images processed in KEK was made possible to be transferred to the computer in Saitama Medical School. 5. Several methods to shift the X-ray energy rapidly between the energies above and below K-edge. 6. Theory for designing the -double stationary crystal method was established.
[Results] a) Contrast resolution depends on photon flux, size of pixl, noise arriving from measurment system, and spatial resolution depends on the surface state of the monochrometer crystal. The relationship between these factors and and image quality was discussed and the crystal parameters should be chosen after the X-ray intensity, spatial resolution, and contrast resolution should be taken into consideration. b) The increase of magnetic field of bending magnets or wigglers leads to the increase of photon flux. However, it also leads to the increase of the fraction of third harmonics. This is one of the factors to prevent the increase of photon flux. We proposed the new acquisition method in which the image of the component of third harmonics was utilized in addition to the images for the energies above and below K-edge. With this method cancellation of bone image was demonstrated. c) As one of the methods of energy shift, we studied the double-crystal method. In this study we demonstrated that the distance between a specrtometric crystal and a subject becomes several hundred meters largely depending on the amounts of energy shift and expansion.
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