Use of ion exchange resin for dynamic PET phantom

A physical phantom that can be used to evaluate the ability of a Positron Emission Tomography (PET) system to perform quantitative dynamic measurements by simulating realistic tissue kinetics was investigated. In this work, the use of ion exchange resin to imitate tracer kinetics in tissue was investigated as a means to construct a realistic dynamic phantom for PET studies. A unit cell perfusion system that demonstrates the feasibility of such an approach was fabricated. The system utilizes competitive binding of ¹³NH₄ ⁺ and Na⁺ for cation exchange resins. Due to the high binding affinity of ¹³NH₄⁺ to cation exchange resin, efficient tracer uptake can be completed, followed by gradual washout of tracer from binding sites by an aqueous solution of NaCl. The clearance rates of tracer can be modified to achieve the desired temporal characteristics by changing either the concentration of NaCl eluent or its flow rate. This unit cell perfusion system was also incorporated into a simple cylinder phantom for dynamic PET imaging. Results from the PET phantom images demonstrated the feasibility of using ion-exchange resin to create dynamic phantoms for PET with easily controlled kinetic characteristics