Synthesis and 68Ga radiolabelling of calcium alginate beads for positron emission particle tracking (PEPT) applications

Abstract

Positron emission particle tracking (PEPT) relies on the back-to-back γ-rays generated through a positron annihilation to track a single radiolabelled particle in three dimensions and in dense, multiphase, and opaque systems. The spectrum of applications of PEPT such as batch mixing systems in chemical, food and pharmaceutical sectors or granulation, die-filling and fluidisation in industrial processes, is directly related to the development of efficient radiolabelled materials and often restricted due to the lack of suitable materials with adequate radiochemical properties. In this work, we report a straightforward synthesis and radiolabelling of calcium alginate beads of different size, specific surface, concentration, and density, with the positron emitter gallium-68 (68Ga) to cover a broad range of possibilities in PEPT. We demonstrate a high intrinsic affinity between alginate and 68Ga providing directly radiolabelled particles with excellent radiochemical properties and excellent performance for tracking complex trajectories. These results, in combination with the availability and relatively simple chemistry of 68Ga, provide a high versatile and straightforward platform for the future development and advance of PEPT in different applications.