A feasibility study of the cyclotron production of²¹Na

Abstract

The cyclotron production of²¹Na, via the²⁰Ne(d, n)²¹Na and the²⁰Ne(³He, pn)²¹Na and²⁰Ne(³He, 2n)²¹Mg →²¹Na nuclear reactions, has been investigated. Transfer of²¹Na from the production target to the medical application site some 10 m distant was achieved by gas phase and liquid phase systems, both of which are described. Under optimal conditions 111 MBq·ml⁻¹ (3 mCi·ml⁻¹) of²¹Na were available at the dispensing reservoir 10 m distant from the production target, when irradiating with a 5 μA deuteron beam current. Incident deuteron energy was degraded to below 3.0 MeV by a 350 μm Al entrance foil, to avoid production of¹⁸F. The charge distribution of²¹Na inside the production target and inside the gas phase transfer tube at distances of 1 m and 15 m were determined, and are reported along with data from similar studies during¹⁸F production via the²⁰Ne(d, α)¹⁸F reaction.²¹Na accumulated primarily at the cathode, indicating the production of positively charged species, whereas¹⁸F was equally distributed between the electrodes in a production target constructed especially for measuring the charge distribution of the radioactive species.