Metascintillators for Ultrafast Gamma Detectors: A Review of Current State and Future Perspectives

Scintillation detector development is an active field of research, especially for its application to the medical imaging field and in particular to the positron emission tomography (PET). Effective sensitivity and signal-to-noise ratio in PET are greatly enhanced when improving detector timing capabilities: the availability to provide time-of-flight (TOF) information. However, physical barriers related to the characteristics of available organic and inorganic scintillators create a tradeoff between photon kinetics and gamma detection efficiency. We introduce the novel concept of metascintillators, composite topologies comprising of multiple scintillating and light-guiding materials functioning in synergy, that break this compromise. We provide an overview of published, ongoing and upcoming developments within this framework. Unconventional topologies, such as the multiple slabs approach comprising of a high-Z host and a fast emitter; materials such as CdSe/CdS nanoplatelets; and treatments related to nanostructured metamaterials and photonic interactions, are reviewed and complemented with new, unpublished advances in simulations and analysis. Future perspectives are further presented, encompassing developments in signal analysis and system integration. Within this concept, an improved generation of detectors and PET scanners with unprecedented time resolution is researched, paving the way toward the 10-ps TOF PET challenge for the advancement of PET and improvement of public health.