Multi-energy, single-isotope imaging using stacked detectors.

Area of Science:

• Nuclear Medicine
• Medical Imaging Physics

Background:

• Current SPECT systems face challenges in simultaneously detecting low- and high-energy photons, particularly from isotopes like Iodine-123.
• Optimizing detector configurations is crucial for improving sensitivity and spatial resolution in small-animal imaging.

Purpose of the Study:

• To develop and evaluate a novel detection scheme for concurrently acquiring low- and high-energy emission images from Iodine-123.
• To assess the efficacy of a stacked silicon double-sided strip detector (DSSD) and modular scintillation camera (Modcam) system with a unique sandwich aperture.

Main Methods:

• Sequential acquisition of low- and high-energy images using a prototype DSSD and Modcam.
• Utilizing a sandwich aperture with a molybdenum insert to selectively block low-energy photons while allowing high-energy photons to pass.
• Employing a multi-pinhole collimator for image decoding and employing MCNP5 simulations for analysis of stacked detectors and aperture performance.

Main Results:

• The molybdenum insert effectively attenuates low-energy (20-30 keV) photons while minimally affecting high-energy (159 keV) photons, reducing cross-talk.
• The sandwich aperture design enhances spatial resolution for low-magnification DSSD images and allows higher magnification on the Modcam.
• MCNP5 simulations indicated potential benefits of stacked detectors and the sandwich aperture for small-animal pinhole SPECT.

Conclusions:

• The developed system demonstrates potential for increased sensitivity in small-animal SPECT compared to single-detector setups.
• The novel sandwich aperture and stacked detector configuration show promise for improved dual-energy imaging of Iodine-123.
• Further construction and testing of the novel aperture with DSSDs are encouraged based on simulation results.