DEVELOPING A PHANTOM FOR THE POSITRONIUM IMAGING EVALUATION

Abstract

In this contribution, a concept for a new phantom for positronium imaging with PET scanners is described. The proposed phantom is based on the NEMA IEC phantom in which six high-activity spheres are filled with solutions characterized by a different mean ortho-positronium lifetime. A method for controlling ortho-positronium lifetime is discussed along with preliminary results. The XAD4 suspended in various fractions of water was tested as a potential model of a sample with a controlled mean lifetime of ortho-positronium. The mean lifetime of ortho-positronium for six samples was estimated by means of the Positronium Annihilation Lifetime Spectroscopy (PALS). Obtained spectra were fitted with the PALS Avalanche analysis program and components corresponding to the ortho-positronium annihilation in the XAD4 pores were established. As a result, the correlations between the lifetime and production intensity of ortho-positronium and the concentration of XAD4 in water were determined.