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No description available.

<p>A novel system has been simulated with accompanying experimental data that is designed to provide spatial information of elemental concentrations at biologically relevant levels. Using a deuterium-deuterium (DD) neutron generator, two large high-purity germanium (HPGe) detectors operating in tandem, and the associated particle imaging (API) technique, elemental iron concentrations as low as 100 ppm have been resolved <i>in vivo</i> in the liver of a simulated reference man with an equivalent dose to the region of interest of < 5 mSv and an estimated whole body dose of 0.82 mSv. Using the Monte Carlo Neutral Particle (MCNP) transport code, achievable spatial resolutions in the projective and depth dimensions of < 1 cm and < 3 cm are achievable, respectively, for iron-containing voxels on the order of 1,000 ppm Fe – with an overall 225 ps system timing resolution, 6.25 mm² imaging plate pixels, and a Gaussian-distributed DD neutron source spot with a diameter of 2 mm. Additionally, as a departure from Monte Carlo simulations, the underlying concepts of fast neutron inelastic scatter analysis as an initial surrogate to true associated particle neutron elemental imaging (APNEI) were demonstrated using a DD neutron generator, iron-made interrogation targets, a sodium iodide detector, and physical neutron/gamma shielding, which yielded an approximate detection limit for iron of 3.45 kg which was simulated to improve to 0.44 kg upon incorporation of the associated particle collimation methodology.</p> The API technique allows concentrations of elements such as iron to be quantified due to time-tagged electronic collimation and corresponding background signal reduction. Inherent to the API process is the collection of spatial and temporal information, which allows the perceived origin of a photon signal to be identified in 3D space. This process was modeled algorithmically in MCNP and employed using relevant equipment and shielding geometries. By leveraging the capabilities of modern-day neutron generator and coincident timing technologies with high throughput signal processing discrimination, the applicability of APNEI to disease diagnostics and etiological research is promising.