Gambaccini M, Tuffanelli A, Taibi A, Del Guerra A
Dipartimento di Fisica dell'Università di Ferrara and INFN Sezione di Ferrara, Italy.
Med Phys. 2001 Apr;28(4):412-8. doi: 10.1118/1.1352578.
A novel x-ray source for mammography application is being investigated. Quasimonochromatic x rays have been produced via Bragg diffraction with a W-anode x-ray tube and a graphite mosaic crystal array. The system provides 18 keV x rays with an energy resolution deltaE/E approximately equals 0.12. A thorough analysis of the spatial resolution of the system has been performed in order to understand and quantify the effect of the introduction of an active optical element such as a mosaic crystal in the x-ray path. The focal spot of the source and its emission properties have been studied by using the slit camera method. Experiments have shown that the introduction of a mosaic crystal in the optical path modifies the resolution properties of the Bragg diffraction-based radiography system. Along the direction perpendicular to the diffraction plane the resolution properties of the imaging system mainly depend on the x-ray tube focal spot size and position. Along the diffraction plane the focal spot size depends on mosaic characteristics and on the geometrical setup. Hence, it could be modified by setting the appropriate experimental conditions.
一种用于乳腺摄影应用的新型X射线源正在研究中。通过布拉格衍射利用钨阳极X射线管和石墨镶嵌晶体阵列产生了准单色X射线。该系统提供能量为18keV的X射线，能量分辨率ΔE/E约等于0.12。为了理解和量化在X射线路径中引入诸如镶嵌晶体之类的有源光学元件的影响，对该系统的空间分辨率进行了全面分析。通过使用狭缝相机方法研究了源的焦点及其发射特性。实验表明，在光路中引入镶嵌晶体改变了基于布拉格衍射的射线照相系统的分辨率特性。在垂直于衍射平面的方向上，成像系统的分辨率特性主要取决于X射线管焦点尺寸和位置。在衍射平面内，焦点尺寸取决于镶嵌晶体特性和几何设置。因此，可以通过设置适当的实验条件对其进行修改。
