巻号一覧
29 巻 (2012)
- 4 号 p. 68-
- 3 号 p. 43-
- 2 号 p. 28-
- 1 号 p. 1-
29 巻, 3 号
選択された号の論文の4件中1～4を表示しています
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教育講演資料
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岡本 博之2012 年 29 巻 3 号 p. 43-50
発行日: 2012年
公開日: 2012/10/03
ジャーナル フリーRecently, a new X-ray imaging technique called phase contrast imaging has been developed. This approach offers improved contrast sensitivity, especially when imaging weakly absorbing specimens. The phase contrast X-ray imaging technique has been successfully used, and is seeing excellent and rapid progress as a diagnostic tool in medicine, biology and materials science. In this paper, we report several methods for the phase contrast X-ray imaging technique.抄録全体を表示PDF形式でダウンロード (1574K)
論文
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Yuichi SATO, Eiichi SATO, Shigeru EHARA, Yasuyuki ODA, Osahiko HAGIWAR ...2012 年 29 巻 3 号 p. 51-55
発行日: 2012年
公開日: 2012/10/03
ジャーナル フリーA photon-counting X-ray computed tomography (CT) system was developed to perform fundamental study on high-speed photon-energy dispersion utilizing scintillation counting. X-ray photons are detected using a YAP (Ce) [cerium-doped yttrium aluminum perovskite] single crystal scintillator with a decay time of 30 ns and an MPPC (multipixel photon counter) module. The photocurrent from the MPPC was amplified by a current-voltage amplifier and an integrator, and the event pulse is sent to a high-speed inverse comparator. Logical pulses are then produced by the comparator and are counted by a counter card. Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan. The image contrast of iodine media decreased with increase in lower-level voltage (Vl) of the comparator. The count rate decreased with increase in Vl, and the maximum count rate was 250 kcps at a Vl of 0.15 V, a tube current of 1.0 mA, and a tube voltage of 70 kV. The exposure time for obtaining a tomogram was 10 min at a scan step of 0.5 mm and a rotation step of 1.0°.抄録全体を表示PDF形式でダウンロード (1428K) -
Yuichi SATO, Eiichi SATO, Shigeru EHARA, Yasuyuki ODA, Osahiko HAGIWAR ...2012 年 29 巻 3 号 p. 56-61
発行日: 2012年
公開日: 2012/10/03
ジャーナル フリーAn energy-dispersive X-ray computed tomography (ED-CT) system is useful for carrying out monochromatic imaging. To perform ED-CT, we developed an oscillation linear cadmium telluride (CdTe) detector with a scan velocity of 25mm/s and an energy resolution of 5keV. CT is performed by repeated linear scans and rotations of an object. Penetrating X-ray photons from the object are detected by the CdTe detector, and event signals of X-ray photons are produced using charge-sensitive and shaping amplifiers. The lower photon energy is determined by a comparator device, and the maximum photon energy of 60keV corresponds to the tube voltage. Logical pulses from the comparator are counted by a counter card. For the ED-CT, the tube voltage and the current were 60kV and 0.40mA, respectively, and X-ray intensity was 16.7µGy/s at 1.0m from the source. The minimum X-ray exposure time was 5min, and demonstration of enhanced iodine K-edge X-ray CT was carried out by selecting photons with energies ranging from 35 to 60keV.抄録全体を表示PDF形式でダウンロード (1964K) -
林 裕晃, 福本 晃, 花光 宏樹, 西原 貞光, 神谷 尚武2012 年 29 巻 3 号 p. 62-67
発行日: 2012年
公開日: 2012/10/03
ジャーナル フリーUsing a Monte-Carlo simulation code, a practical method to calculate the X-ray spectrum in the radiography was proposed. The geometry used in the simulation was composed of the target and total filtration. This geometry could calculate both the generation of the X-rays at the target and its attenuation in the total filtration. The features of this method are to simulate the heal effect and to obtain the X-ray spectrum corresponding to the all irradiated field. Because it was difficult to reproduce the electric field in the simulation, almost all incident electrons were scattered at the target and some of them were converted to the bremsstrahlung X-rays in the total filtration. This phenomenon did not occur in the real X-ray equipment. Therefore, we considered that our method was appropriate to use a case in which the bremsstrahlung X-rays generated in the total filtration was negligibly-small compared with the X-ray spectrum generated at the target. We investigated the possibility to apply the method for the tube voltage of 40-120 kV. As a result, we found that a fraction of inessential bremsstrahlung X-rays was at most 0.4%. Namely, using the proposed method, the X-ray spectrum can be reproduced with accuracy of 0.4%.抄録全体を表示PDF形式でダウンロード (1037K)
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