Electron Spin Resonance Spectroscopy (ESR) was developed in 1945. The instrument is recently take notice of some applications. In particular, it has been interested in the relation between active oxygens and free radicals, and disease. In this report, the theory of ESR and tipical applications in biological fields were described.

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A grid used in radiography is effective to reduce x-rays scattered in a patient. To evaluate the reducing characteristics of grid quantiatively, we have developed a Monte Carlo method to simulated the radiographic conditions including grid and calculated the Bucky factor, selectivity, and, contrast improvement factor, for vaious parameters such as grid ratio, field size et al. The results show that our calculation data agree with mesurement one, and may give good information to select a suitable grid, with the aim of reducing medication dosage and optimizing image quality.

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We have calculated scatter to primary X-ray ratios at detector position in the cone-beam 3D X-ray CT scanner using the Monte Carlo simulation and evaluated the effects of scatter on reconstructed images. Without bow-tie filter, the intensity of scatter at detector center is twice as much as that of primary for water phantom of 11.5cm rasius, and the CT number of reconstructed image fall by about 30 % at center. With bow-tie filter, the scatter ratio to primary at center decrease largely and the CT number fall by about 10 % in the whole image. Furthermore, the usage of the filter decreases in absorbed dose of 60% compare with no usage of filter.

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A Hi-8 moving-image processing system with low noise and high spatial resolution is constructed by using a Hi-8 video cassette recorder with frame memory and a IBM-PC computer installed with a frame grabber board. Subsequently, a program to detect artery pulsation from a series of ultrasoundecho moving images of a newborn baby's head is developed, based on the discrete Fourier transform of the time-sequence variation of pixel value. It is then demonstrated that a weak artery pulsation is successfully detected, besides anterior, posterior, middle cerebral artery, anterior choroidal artery, circle of Willis, and basilar artery pulsations.

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