Production and Processing of the Radionuclide 76Br

Four-dimensional visualization, i.e., three-dimensional space plus time, of fluid flow and its interactions in geological materials using positron emission tomography (PET) requires suitable radiotracers that exhibit the desired physicochemical interactions. 76Br is a likely candidate as a conservative tracer in these studies. [76Se]CoSe was produced and used as the target material for the production of 76Br via the (p,n) reaction at a Cyclone 18/9 cyclotron. 76Br was separated from the target by thermochromatographic distillation using a semi-automated system, combining a quartz glass apparatus with a synthesis module. 76Br was successfully produced at the cyclotron with a physical yield of 72 MBq/µAh (EOB). The total radiochemical yield of 76Br from the irradiated [76Se]CoSe target (EOS) was 68.6%. A total of 40 MBq–100 MBq n.c.a. 76Br were routinely prepared for PET experiments in 3 mL 20 mM Cl− solution. The spatial resolution of a PET scan with 76Br in geological materials was determined to be about 5 mm. The established procedure enables the routine investigation of hydrodynamics by PET techniques in geological materials that strongly sorb commonly used PET tracers such as 18F.