Attenuation Correction of L-shell X-ray Fluorescence Computed Tomography   Imaging
  X-ray Fluorescence Computed Tomography(XFCT) is a prevalent experimental technique which is utilized to investigate the spatial distribution of elements in sample. The sensitivity of L-shell XFCT of some elements is lower than that of K-shell XFCT. However, the image reconstruction for this technique has much more problems than that of transmission tomography, one of which is self-absorption. In the present work, a novel strategy was developed to deal with such problems. But few researches are concerned on attenuation correction of L-shell XFCT that are essential to get accurate reconstructed image. We make use of the known quantities and the unknown elemental concentration of interest to express the unknown attenuation maps. And then the attenuation maps are added in the contribution value of the pixel in MLEM reconstruction method. Results indicate that the relative error is less than 14.1%, which is proved this method can correct L-shell XFCT very well. 
Liu Long, Huang Yang, Ma Bo, Xu Qing, Yan Lingtong, Li Li, Feng   Songlin, Feng Xiangqian
physics.ins-det physics.med-ph