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Volume 5 (1988)
- Issue 3 Pages 93-
- Issue 2 Pages 37-
- Issue 1 Pages 1-
Volume 5, Issue 2
Displaying 1-5 of 5 articles from this issue
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S. HASEGAWA, A. SUWA, H. FUKAGAWA, M. AKISADA, M. ANDO, K. HYODO, K. K ...1988 Volume 5 Issue 2 Pages 37-44
Published: 1988
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSDownload PDF (2334K) -
Katsuhiko UEDA, Junji MORISHITA, Tsuyoshi FUJIKAWA, Akiyoshi OHTSUKA, ...1988 Volume 5 Issue 2 Pages 52-59
Published: 1988
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSWe measured the system response of a computed radiographic (CR) system with photostimulable phosphors (imaging plate: IP), as three different types of curves, which are the “digital” characteristic curve relating the output pixel value to the input relative x-ray intensity, the calibration curve relating the output photographic density to the input pixel value, and the “overall” characteristic curve relating the output density to the input relative x-ray intensity. The digital characteristic curves showed a considerably wider dynamic range (102.83) than that of the conventional screen-film system. However, this measured dynamic range was narrower than the nominal dynamic range (103.3) of the CR system. The measured sensitivity of the CR system, on the other hand, agreed with the nominal sensitivity. Calibration curve and overall characteristic curve were linear on the plot within the density range of approximately 0.4 to 2.64. These curves measured in our study are useful for quantitative analysis in a CR system.View full abstractDownload PDF (2349K) -
Hideaki KUBOTA, Masao MATSUMOTO, Hitoshi KANAMORI1988 Volume 5 Issue 2 Pages 60-68
Published: 1988
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSIn order to measure X-ray spectra of scattered radiation together with primary beam by using a planar Ge detector, we have measured the angular dependence of the response of the detector for obliquely incident pbotons of241 Am γ-rays. As a result, the active area of a 10mmφ×7mm detector: is 7mm in diameter and the available incident an is within 20°.
Taking into account these properties of the detector, we prepared conic Pb collimators whose maximum incident angle is 13°. Because high-energy photons penetrate the edge of the collimayor, it is unable to convert measured photon spectrum in photon counts into that per unit area only by dividing by the geometrical area of the smallest hole of the collimator. To solve this problem, we have corrected measured photon spectrum by avoiding the photons which penetrated the edge of the conic Pb collimator. In this correction, the shape of the collimator and linear attenuation coefficient of Pb were used.We carried out the measurement of photon spectra with scattered radiation using objects of 30mm Al and 25cm acrylic resin for various object-collimator distances. Experimental spectra had a good agreement with spectra calculated by using Monte Carlo method.View full abstractDownload PDF (1435K) -
Eiichi SATO, Satoshi KAWASAKI, Hiroshi ISOBE, Jutaro TAKAHASHI, Makiko ...1988 Volume 5 Issue 2 Pages 69-75
Published: 1988
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSA method for generating soft x-rays for biomedical radiography using a universal x-ray generator having a cold cathode radiation tube is described. This universal generator consisted of the following essential components: various kinds of pulsed high-voltage generators corresponding to the radiographic objectives, a vacuum pump, and an oil-cooled x-ray tube using field emission. For generating the soft x-rays, a Cockcroft circuit having a DC-AC inverter with a frequency of about 2kHz was employed. The x-ray intensity of this generator varied according to the electric power of the DC-AC inverter, the tube voltage, the tube current, the anode material, and others. The effective focal spot size was determined by the diameter of the anode tip.. Various kinds of soft radiographs were obtained.View full abstractDownload PDF (1540K) -
Hiroshi ISOBE, Eiichi SATO, Satoshi KAWASAKI, Takeshi AKITSU, Soukou O ...1988 Volume 5 Issue 2 Pages 76-81
Published: 1988
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSThe construction and the radiographic characteristics for a single pulsed x-ray and electron beam generator are described. This generator consisted of the following components: a high voltage power supply for negative voltage, a high-voltage coaxial condenser, a low-impedance coaxial transmission line, a pulsed x-ray and electron beam tube using field emission. The electric charge stored by the condenser was discharged to the radiation tube when the gap switch was closed. This tube produced pulsed (flash) x-rays through various kinds of foil anodes. The electron beam primarily consisted of ionized electrons outside of the anode window due to the production of a high dose rate of pulsed xrays, and these electrons were slightly accelerated by the electric field between the anode and the ground. Both kinds of radiation were produced simultaneously.View full abstractDownload PDF (1784K)
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