[Show abstract][Hide abstract] ABSTRACT: AN00054674 When linear accelerator exceeds 10MV, it produces photonuclear reaction, and generates continuous energy. Measuring devices are very few in number and determination of energy spectrum is very difficult. This paper is designed to show the result of survey made by bubble detectors.
[Show abstract][Hide abstract] ABSTRACT: AN00054674 A technique is suggested for estimation of contrast medium using white and charactristic x-rays absorptiometry. The measurment of K-absorption edge using spectrometry of transmitted white x-ray is more practical than charactristic x-rays absorptiometry. Quantitative estimation of bone mineral in phantom is investigated by La-Kα, Kβ, radiation absorptiometry using highper pure Ge detector. Laの特性X線を利用するとバリウムとヨウ素の識別は容易であるが、臨床応用のためには充分な強度の特性X線を得ることに問題がある。透過X線のエネルギースペクトルを測定してK吸収端のエネルギーから物質の識別をする方法が現実的である。高エネルギー分解能の検出器を使用するとLaの特性X線の減弱率から骨塩量の精度良い測定が可能である。
[Show abstract][Hide abstract] ABSTRACT: 九州大学医療技術短期大学部(坂本, 上原) 九州大学アイソトープ総合センター(吉村) 九州大学医学部附属病院(入江, 泉, 齋藤) AN00054674 Two methods measuring neutrons generated in a medical accelerator were investigated. One is the activation method using concentrated Argon gas with a fixed pressure sealed in a glass vessel. Gamma-rays from 41Ar was measured with Ge detector and its counting efficiency was obtained by a Monte Carlo calculation. This new method showed the sensitivity of 56 times higher than that of the irradiation with natural air. Another method is to use the neutron sensitive bubble damage polymer detector. The measurement of neutrons generated in 10 MV Linear Accelerator was tried by these methods.
[Show abstract][Hide abstract] ABSTRACT: AN00054674 The measured accuracy of the X-ray attenuation curves depends on the variations of the tube voltage, the tube current and the exposure time, so that the accurate measurement of this curve is very difficult. The measuring method was improved to minimize the error coming from these variations by employing a transmission ionization chamber which was used to estimate the incident dose. The authors took the ratio of the attenuated dose to the incident dose measured at the same time, in consequence, the measured accuracy increased effectively. The present method also made it possible to obtain the attenuation curve of a short exposure time.
[Show abstract][Hide abstract] ABSTRACT: AN00054674 The characteristics of X-ray generators can be simply and safely measured by a non-invasive X-ray analyzer in comparison with an electric meter. Non-invasive X-ray analyzer 'KYOKKO model 100' has been used for measuring of X-ray generators in our laboratory. The present results further support the view that this method is very useful for the quality control of X-ray generators.