Bright Lu₂ O₃ :Eu Thin-Film Scintillators for High-Resolution Radioluminescence Microscopy

The performance of a new thin-film Lu₂ O₃ :Eu scintillator for single-cell radionuclide imaging is investigated. Imaging the metabolic properties of heterogeneous cell populations in real time is an important challenge with clinical implications. An innovative technique called radioluminescence microscopy has been developed to quantitatively and sensitively measure radionuclide uptake in single cells. The most important component of this technique is the scintillator, which converts the energy released during radioactive decay into luminescent signals. The sensitivity and spatial resolution of the imaging system depend critically on the characteristics of the scintillator, that is, the material used and its geometrical configuration. Scintillators fabricated using conventional methods are relatively thick and therefore do not provide optimal spatial resolution. A thin-film Lu₂ O₃ :Eu scintillator is compared to a conventional 500 μm thick CdWO₄ scintillator for radioluminescence imaging. Despite its thinness, the unique scintillation properties of the Lu₂ O₃ :Eu scintillator allow us to capture single-positron decays with fourfold higher sensitivity, which is a significant achievement. The thin-film Lu₂ O₃ :Eu scintillators also yield radioluminescence images where individual cells appear smaller and better resolved on average than with the CdWO₄ scintillators. Coupled with the thin-film scintillator technology, radioluminescence microscopy can yield valuable and clinically relevant data on the metabolism of single cells.