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Neutron activation for planar and SPECT imaging

A new approach to SPECT and planar imaging has been proposed which uses neutron-activated tracers in place of traditional radioisotopes. A preliminary experiment was conducted to assess the feasibility of the proposed method. A Rose model-style phantom was imaged using 131I as a proxy for a particular neutron activated isotope with a similar primary photon energy. Poisson noise caused by hydrogen neutron activation was modeled mathematically and added to the phantom images during post-processing. A range of hotspots in the phantom were evaluated by visual inspection and calculation of their SNR. Hotspots larger than 2 cm in diameter were easily visible for a 5 minute image, while a 1 cm hotspot was detectable for spot-view imaging times over 25 minutes. Dose rate estimates, using experimental data and assuming a general imaging scenario, are 0.059–3.9 mSv/min for tissue exposed to the neutron beam. Neutron-activated imaging shows potential and warrants further study.