|Title||Joint Reconstruction of X-Ray Fluorescence and Transmission Tomography |
|Publication Type||Journal Article |
|Year of Publication||2017 |
|Authors||Di, Z, Chen, S, Hong, Y, Jacobsen, C, Leyffer, S, Wild, SM |
|Journal||Optics Express |
|Abstract||X-ray fluorescence tomography is based on the detection of fluorescence x-ray photons produced following x-ray absorption while a specimen is rotated; it provides information on the 3D distribution of selected elementals within a sample. One limitation in the quality of sample recovery is the separation of elemental signals due to the finite energy resolution of the detector. Another limitation is the effect of self-absorption, which can lead to inaccurate results with dense samples. To recover the true elemental map, we combine x-ray fluorescence detection with a second data modality: conventional x-ray transmission tomography using either absorption or phase contrast. By using these combined signals in a nonlinear optimization-based approach, we obtain an improved quantitative reconstruction of the spatial distribution of most elements in the sample. Compared with single-modality inversion based on x-ray fluorescence alone, this joint inversion approach reduces ill-posedness and results in improved elemental quantification and better correction of self-absorption.