Fast emitting nanocomposites for high-resolution ToF-PET imaging based on multicomponent scintillators

TL;DR

This paper introduces a nanocomposite scintillator with enhanced density and light yield, improving the timing resolution in ToF-PET imaging by combining fast emission properties with high density.

Contribution

The study presents a novel multilayer nanocomposite scintillator that significantly improves coincidence time resolution in ToF-PET by integrating dense hafnium oxide nanoparticles with a fast-emitting polymeric scintillator.

Findings

Scintillation yield increased by +300% with hafnium oxide nanoparticles.

Achieved a 25% improvement in coincidence time resolution over monolithic BGO.

Demonstrated effective energy sharing in multilayer scintillator design.

Abstract

Time-of-Flight Positron Emission Tomography is a medical imaging technique, based on the detection of two back-to-back {\gamma}-photons generated from radiotracers injected in the body. Its limit is the ability of employed scintillation detectors to discriminate in time the arrival of {\gamma}-pairs, i.e. the coincidence time resolution (CTR). A CTR < 50 ps that would enable fast imaging with ultralow radiotracer dose. Monolithic materials do not have simultaneously the required high light output and fast emission characteristics, thus the concept of scintillating heterostructure is proposed, where the device is made of a dense scintillator coupled to a fast-emitting light material. Here we present a composite polymeric scintillator, whose density has been increased upon addition of hafnium oxide nanoparticles. This enhanced by +300% its scintillation yield, surpassing commercial plastic scintillators. The nanocomposite is coupled to bismuth germanate oxide (BGO) realizing a multilayer scintillator. We observed the energy sharing between its components, which activate the nanocomposite fast emission enabling a net CTR improvement of 25% with respect to monolithic BGO. These results demonstrate that a controlled loading with dense nanomaterials is an excellent strategy to enhance the performance of polymeric scintillators for their use in advanced radiation detection and imaging technologies.