ON-CHIP PURIFICATION OF [ 18 F]FDG IN POSITRON EMISSION TOMOGRAPHY RADIOTRACER SYNTHESIS Mark D. Tarn 1 , Giancarlo Pascali 2 , Francesco De Leonardis 1 , Paul Watts 1 , Piero A. Salvadori 2 and Nicole Pamme 1 1 Department of Chemistry, The University of Hull, Cottingham Road, Hull HU6 7RX, UK 2 Department of Radiopharmaceutical Chemistry, CNR Institute of Clinical Physiology, 56124 Pisa, ITALY ABSTRACT We demonstrate the use of microfluidic modules for purification of the Positron Emission Tomography (PET) radiotracer, 2-deoxy-2-[ 18 F]fluoro-D-glucose ([ 18 F]FDG), as part of an integrated microfluidic Radiochemistry-On-Chip (ROC) platform for complete radiotracer synthesis. Two different modules were applied to the purification of [ 18 F]FDG as synthesized by a commercial system and by initial tests of the ROC platform itself. KEYWORDS [ 18 F]FDG, Positron Emission Tomography (PET), purification, radiochemistry, solid-phase extraction (SPE). INTRODUCTION Positron Emission Tomography (PET) is a molecular imaging technique involving the injection into a patient and sub- sequent monitoring of a radioisotope (e.g. [ 18 F]fluoride) labeled drug molecule (radiotracer), and is employed as a diag- nostic tool in oncology, cardiology, and the neurosciences. Although many different radiotracers are available, the most common is glucose labeled with [ 18 F]fluoride: 2-deoxy-2-[ 18 F]fluoro-D-glucose, better known as [ 18 F]FDG. [ 18 F]FDG, as well as other radiotracers, is manufactured via the use of automated synthesizers housed within heavily shielded and bulky “hot cells”. Due to the half-life of the radioisotope and the limited quantities produced by a cyclotron prior to radiotracer manufacture, each step of the synthesis must be carried out rapidly and with high efficiency. In recent years, micro- fluidic devices have shown great promise in the synthesis of PET radiotracers thanks to rapid synthesis times and minimal shielding requirements [1-3]. However, most reported devices focus only on the synthesis step of the procedure or, to a lesser extent, the radioisotope pre-concentration step prior to the synthesis, neglecting other key processes in the produc- tion that could equally benefit from miniaturization. In particular, on-chip purification of the final radiotracers has not been explored, instead being achieved off-line via conventional solid-phase extraction (SPE) cartridges with large dead volumes. As part of a European Union FP7 project and in collaboration with Siemens, we have been developing a “Radio chemistry-On-Chip” (ROC) platform that incorporates all aspects of the synthetic procedure into a modular microfluidic platform. Previously, we presented a module for the pre-concentration of [ 18 F]fluoride from irradiated water for subse- quent radiotracer synthesis [4,5]. Here, we extend this technique further and demonstrate microfluidic modules for the pu- rification of [ 18 F]FDG, synthesized by (i) a commercial Advion NanoTek system utilizing a capillary-based microreactor, and (ii) initial tests of the ROC platform itself. Figure 1: (a) Schematic of the chip design, consisting of a bottom plate etched to a depth of 250 m, and a top plate etched to 50 m. When bonded, they formed a 300 m deep chamber with a shallow triangular section acting as a dam to trap particles. (b) Single module containing all four SPE particle types required for [ 18 F]FDG purification. Each chamber was filled with two of the resins, and the outlet of the upper chamber was routed into the inlet of the lower chamber. (c) Train of purification modules, with each chamber containing only one type of particle, thereby doubling the trapping capacity compared to the single module. The outlet of each module was connected to the inlet of the next, al- lowing solutions to pass through each chamber consecutively. 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences October 28 - November 1, 2012, Okinawa, Japan 978-0-9798064-5-2/μTAS 2012/$20©12CBMS-0001 1795