Performance Evaluation of SPECT Imaging System for Sediment Column Imaging

The performance of a SPECT imaging system for imaging vertically oriented glass columns (10 cm diameter x 30 cm long) has been evaluated in terms of spatial resolution, image uniformity, and linearity. This imaging system was developed to support research in environmental geosciences by determining flow patterns in heterogeneous porous media (e.g., sediment) through simultaneous monitoring of sediment chemistry and flow parameters. Using a Derenzo-like hot-rod phantom, rods down to 7.9 mm diameter were resolved. Flood images had an integral uniformity of 8.5% and differential uniformity of 6.2% in the center of the field of view. The ratio of total detected counts to the mean image reconstructed value was within 2% of linear over a range of greater than two orders of magnitude of counts.