Single element mapping in radiography

This article reports on the application of element-specific mapping using the Bremsstrahlung of a commercial broad spectrum X-ray source to map lighter elements (zirconium to tin) and heavier elements (tantalum to bismuth) individually within an image field. Grey level or image brightness has been obtained as a function of acceleration potential over a range of 15–75 kV for lighter elements and 55–150 kV for heavier elements at 1 kV intervals. Tikhonov regularisation was applied to the experimental grey level functions, using a model of the spectrum, to enhance spectral features associated with elemental K-edges. These features were then used to test for a specific element at all points within an X-ray image in order to map its presence over the whole image field. Hence it has been shown that it is possible to map specific target elements within an image, provided the grey level function over an appropriate energy range is known at all points. Copyright © 2009 John Wiley & Sons, Ltd.