Abstract / Summary
This study aims to quantitatively evaluate the imaging performance of 111 Ag in a preclinical planar SPECT system, with emphasis on scatter correction optimization and multi-photopeak acquisition for accurate activity estimation. A phantom-based study was conducted using the γ-eye preclinical planar imaging system. Imaging was conducted at the three principal γ emissions of 111 Ag (96.7, 245.4, and 342.1 keV). Calibration measurements using activity-filled vials were used to assess system linearity and sensitivity. A mouse phantom was employed to evaluate quantitative accuracy under realistic activity distributions. Scatter correction was performed using the Triple-Energy Window (TEW) method, and a multi-photopeak acquisition approach was applied to improve sensitivity. All three photopeaks were clearly detected, enabling multi-energy imaging. Optimized TEW parameters (± 15% main window, ± 10 keV side windows) showed the best balance between sensitivity, signal-to-noise ratio, and quantification accuracy. A strong linear relationship between count rate and activity was observed (R 2 > 0.99). Quantitative analysis of the mouse phantom demonstrated good agreement between measured and reference activity values, with improved sensitivity achieved through multi-photopeak summation while maintaining accuracy. Quantitative planar imaging of 111 Ag is feasible and reliable when combining optimized TEW scatter correction with multi-photopeak acquisition. The proposed methodology enables accurate activity estimation and provides a robust framework for preclinical dosimetry, supporting the further development of 111 Ag as a theranostic radionuclide.