Theoretical evaluation of a novel method for producing fluorine-18 for Positron-emission-tomography (PET) applications utilizing the 3He(d,p)4He reaction.

A novel method of producing fluorine-18 for Positron emission tomography (PET) scan applications is evaluated theoretically. The method is based upon the 3He(d,p)4He nuclear reaction from which the protons produced are used to produce fluorine-18 via the 18O(p,n)18F reaction. The potential advantage of such a system over cyclotron-based production is of lower input beam energy, which may lower the cost of the system and potentially allow for onsite production. Two theoretical designs were investigated. The first utilizes a helium-3 beam incident on a deuterated plastic target such as Mylar which is backed with an oxygen-18 heavy-water (H2O18) target. The second design utilizes a super-heavy-water (D2O18) target effectively combining both targets into one. Theoretical yield calculations were performed for both designs and the practicalities, primarily those of thermal and target degradation effects were assessed. To produce sufficient fluorine-18 yield a 1 MeV helium-3 beam at 100 mA was simulated. For this beam it was calculated that 310 MBq of fluorine-18 activity, as required to scan a 74 kg patient would be generated in a 69 min or an 18 min production run for the Mylar and super-heavy-water systems respectively. The simulated beam is at 100 kW power and without significant cooling would vaporize the target materials with the melting point of Mylar and boiling point of water calculated to be breached within 0.41 μs and 0.45 μs from beam-on. To achieve sufficient fluorine-18 yield the helium-3 beam power had to be increased to impractical levels making the systems technically infeasible.