RESUMEN
X-ray excited fluorescence tomography is an emerging field in the application of bio-imaging and computer tomography. Some rare-earth doped inorganic phosphors like gadolinium oxide (Gd2 O3 ), yttrium oxide (Y2 O3 ), zinc tungstate (ZnWO4 ), cesium fluoride (CsF), barium fluorochloride (BaFCl), lanthanum oxybromide (LaOBr) are shown outstanding applications for X-ray excited phosphors. Gadolinium (Gd)-based inorganic phosphors show extraordinary applications in the field of X-ray chromatography and computer chromatography. In this review article, we discussed the general information about X-ray excited luminescence (XEL) phosphor. Further, we discussed importance, synthesis, structural and photoluminescence (PL) properties of rare-earth (Europium (Eu)) doped Gd2 O3 . To elaborate the scope of the review, we have discussed synthesis, structural and optical properties of lithium (Li) doped Gd2 O3 :Eu. At the end of the review, synthesis, structural and optical properties of Eu doped lutetium oxide (Lu2 O3 ) have been discussed and the results compared with Eu doped Gd2 O3 . The comparison provided the understanding of structural and optical peak position of host and the dopant (Eu).