Multicolor Long-Term Single-Particle Tracking Using 10 nm Upconverting Nanoparticles.

Single-particle tracking (SPT) is a powerful technique to unveil molecular behaviors crucial to the understanding of many biological processes, but it is limited by factors such as probe photostability and spectral orthogonality. To overcome these limitations, we develop upconverting nanoparticles (UCNPs), which are photostable over several hours at the single-particle level, enabling long-term multicolor SPT. We investigate the brightness of core-shell UCNPs as a function of inert shell thickness to minimize particle size while maintaining sufficient signal for SPT.

Simulation of a Compton-based detector for low-dose high-resolution time-of-flight positron emission tomography.

Two major challenges in time-of-flight positron emission tomography (TOF-PET) are low spatial resolution and high radioactive dose to the patient, both of which result from limitations in detection technology rather than fundamental physics. A new type of TOF-PET detector employing low-atomic number (low-Z) scintillation media and large-area, high-resolution photodetectors to record Compton scattering locations in the detector has been proposed as a promising alternative, but the minimum technical requirements for such a system have not yet been established. Here we present a simulation study evaluating the potential of a proposed low-Z detection medium, linear alkylbenzene (LAB) doped with a switchable molecular recorder, for next-generation TOF-PET detection.