Experimental Evaluation of DE-SPECT: A Hyperspectral SPECT System for Region-Selective 3-D Gamma-Ray Spectroscopy

This study presents an experimental evaluation of the Dynamic Extremity SPECT (DE-SPECT) system, specifically engineered for precise, region-selective gamma-ray spectroscopy in the diagnosis of Peripheral Vascular Disease (PVD) in lower extremities. The system incorporates Cadmium Zinc Telluride (CZT) imaging spectrometers and dynamic dual-field-of-view (FOV) collimators to facilitate comprehensive, multifunctional molecular imaging. The CZT detectors, with Depth of Interaction (DOI) capabilities, deliver an exceptional energy performance across a wide energy range up to 600 keV. The novel dual-FOV aperture system allows selective imaging with two configurations: a 28-cm diameter wide FOV suitable for dual-leg or scout imaging and a 16-cm diameter high-resolution, and high-sensitivity (HR-HS) FOV designed for single-leg or focused imaging. Utilizing uniform phantoms, resolution phantoms, and multi-tracer phantoms, we experimentally assessed the system's sensitivity, spatial resolution, and multi-tracer imaging capabilities. Spatial resolutions were approximately 6 mm in HR-HS-FOV mode and between 8 mm to 10 mm in wide-FOV mode. Peak-to-Valley ratios, indicative of image clarity, improved with enhanced DOI resolutions, rising from 1.03 to 1.22. The system's ability to perform multi-tracer imaging, essential for deriving multifunctional molecular information, further highlights its potential to significantly enhance diagnostic accuracy for PVD.