title: Optimization of nano-phosphor synthesis by including sensitizer doping for medical X-ray imaging.
abstract: Medical radiation imaging systems employ phosphors such as CaWO4 as X-ray receptor materials. Unfortunately, the conversion efficiencies of these materials are rather low (approx. 5%). Alternatives that comprise a bulk structure have been fabricated from rare earth metals, but they are not efficient enough to produce high quality images. Nano-phosphors do not suffer from the limitations inherent to the bulk structures of conventional phosphors. We examined the effects of sensitizer doping conditions on the optical characteristics and morphology of the rare earth phosphor Gd2O3:Eu to fabricate a novel type of nano-phosphor. We optimized a temperature solution-combustion procedure for producing phosphors doped with 5 wt% Eu. Scanning electron microscopy images showed that the phosphors were 20-30 nm in diameter and X-ray diffraction analysis revealed that they underwent polycrystalline growth upon the addition of a sensitizer, similar to the polycrystalline growth of bulk phosphors. In addition, the phosphors exhibited a strong peak at 613 nm and luminescence similar to conventional phosphors. Phosphors that were produced using citric acid as a sensitizer showed more than double the level of luminescence and could be used to produce higher quality images compared to non-sensitized phosphors. The phosphors also exhibited a high degree of luminescence stability.
authors.affiliation: Department of Medical Image Science, Inje University, 621-749 Gimhae, Republic of Korea.
authors.forename: Ji-Na
authors.initials: JN
authors.lastname: Kim
authors.forename: Jung-Wook
authors.initials: JW
authors.lastname: Shin
authors.forename: Kyung-Min
authors.initials: KM
authors.lastname: Oh
authors.forename: Young-Kyu
authors.initials: YK
authors.lastname: Lee
authors.forename: Sung-Kwang
authors.initials: SK
authors.lastname: Park
authors.forename: Ji-Kun
authors.initials: JK
authors.lastname: Park
authors.forename: Sang-Hee
authors.initials: SH
authors.lastname: Nam
mesh_terms: D005682:Gadolinium / Q000737:chemistry* / Q000528:radiation effects*; D008163:Luminescent Measurements / Q000379:methods*; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects* / Q000648:ultrastructure; D010316:Particle Size; D011859:Radiography / Q000379:methods*; D014965:X-Rays
chemical_list: C030581:gadolinium oxide; D005682:Gadolinium