Experimental comparison of high-density scintillators for EMCCD-based gamma ray imaging

Area of Science:

• Materials science
• Medical imaging physics
• Nuclear instrumentation

Background:

• Electron-multiplying charge-coupled devices (EMCCDs) enable high-resolution X-ray and gamma-ray detection.
• Current EMCCD gamma cameras are limited by scintillator material choices, particularly those with fast decay times.
• Longer decay time scintillators were previously unsuitable for photon-counting gamma cameras.

Purpose of the Study:

• To evaluate novel dense scintillators as alternatives to CsI:Tl for EMCCD-based gamma cameras.
• To assess the impact of scintillator material properties on spatial and energy resolution.
• To explore the potential of 'slow' scintillators for improved gamma camera performance.

Main Methods:

• Tested CdWO₄, Lu₂O₃:Eu, and (Gd,Lu)₂O₃:Eu scintillators against CsI:Tl.
• Ensured equal 140 keV interaction probability (66%) for all tested materials.
• Evaluated performance based on spatial and energy resolution using gamma camera metrics.

Main Results:

• CdWO₄, Lu₂O₃:Eu, and (Gd,Lu)₂O₃:Eu demonstrated significantly improved spatial resolution compared to CsI:Tl.
• Lu₂O₃:Eu transparent ceramic achieved the best spatial resolution at 65 µm FWHM.
• The improved spatial resolution came at the cost of reduced energy resolution.

Conclusions:

• 'Slow' dense scintillators, including CdWO₄ and Lu₂O₃:Eu, are viable for EMCCD-based gamma cameras.
• These materials significantly enhance spatial resolution, opening new avenues for imaging applications.
• Further research into optimizing these scintillators could lead to next-generation gamma camera technology.