Energetic analysis of composite of filter for the low contrast improvement of IVR

为了对人体组织进行无创成像，使用了x射线、超声波和核磁共振成像。利用不同组织性质的线性衰减系数之间的差异进行放射诊断是最普遍的。由于其在骨骼软组织和空气包络器官溶液肌肉组织上的线性衰减系数差异很大，因此在成像时易于识别其侧面的变化和变形。在人体组织中，由于主观对比小，在肌肉组织和软组织的细微变化上，线性衰减系数的差异减小。为了提高主观对比度，降低有效能量会增大线性衰减系数的差值。那么就有可能在大的变化中提高诊断。然后，将管电压调高，通过增加滤光片，对多次曝光的低能量进行处理，同时吸收对对比度不利的高能量分量。在此基础上，报道了铌、钼、铑等K吸收滤光片与铝、铜等滤光片相比降低（20KeV左右），且高能区磁导率高，低能区磁导率下降大。因此，在高能区的分析中，最优厚度分析和铝、铜的多重过滤似乎是必要的。分析结果如下。1)当考虑到诊断x射线设备的x射线光谱时，应使用与人体组织成分评价最相似的Mix-Dp。2)对于K吸收边能量高的加钨滤光片，0.001cm的厚度是足够的。3)当选用K吸收边能量较低的材料时，选用原子序数比铌原子序数低的材料即可。4)当使用K吸收边能量较低的材料时，薄膜的散射辐射含量率和γ不同，厚度也不同。少

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 … More 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