| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1999: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
To image the human tissue in noninvasion, X-rays, ultrasonic waves and MRI are used. The radiological diagnosis using the difference between linear attenuation coefficients which differs by the property of the organization is the most general. The recogntition of the change and deformation of the aspect are easy, when it was imaged, because the linear attenuation coefficient is greatly different on it in bones and soft tissue and air inclusion organ solution muscular tissue. In the human tissue, the exposure condition is examined, because the difference of linear attenuation coefficient lowers on the delicate change of muscular tissue and soft tissue as subjective contrast small. The difference of the linear attenuation coefficient increases if the effective energy is lowered in order to improve the subjective contrast. Then it is possible that the diagnosis is improved in large change. Then, the tube voltage is set high, and the low energy with many exposures using added filter is rem
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oved, and in addition, high energy component which does the contrast bad is absorbed. On this, it was reported that the filters of K absorption edues (around 20KeV) such as niobium, molybdenum, rhodium compared with the filters of aluminum, copper, and that the permeability of the high energy region is high, and that the decrease of the low energy region is large. Therefore, the optimum thickness analysis and the multiple filter of aluminum and copper seem to be necessity in the analysis in the high energy region. The results of these analysis are followed.
1) Mix-Dp which is the most similar for the human tissue composition to the evaluation of the test object contrast when an X-ray spectrum from diagnostic X-ray apparatus is considered, should be used.
2) The thickness of 0.001cm is adequate for the tungsten added filter in which the energy of the K absorption edge is high.
3) The material of the atomic number which is lower than atomic number of the niobium is adequate, when the material in which the energy of the K absorption edge is low is used.
4) The thickness is different by the scattered radiation content rate and γ of the film, when the material of the energy in which the K absorption edge is low is used. Less
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