Polymer-based substrates for potential generation of nitrogen-13 for positron emission tomography

Nitrogen-13 is a medically useful positron-emitting isotope with applications in Positron Emission Tomography (PET). Target materials currently available for the production of nitrogen-13 possess a number of deficiencies. New polymer-based materials are being evaluated in an effort to improve nitrogen-13 production on medical cyclotrons. A series of microscopic, spherical poly(styrene/divinylbenzene) derivatives have been synthesized via suspension polymerization and then pyrolyzed to form carbonized beads. Deuteron irradiation studies have been conducted at UCLA using a 22 MeV multi-particle cyclotron on pyrolyzed particles that possess the desired properties (e.g., size, shape, overall yield). The stability of the beads upon irradiation, and the yields of nitrogen-13 at end of bombardment (EOB) as well as the purity of nitrogen-13 labelled ammonia were investigated.