Design optimization of multi-pinhole micro-SPECT configurations by signal detection tasks and system performance...

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Biomedical Engineering

Background:

• Pinhole Single-Photon Emission Computed Tomography (SPECT) is crucial for small animal imaging, but optimizing spatial resolution and sensitivity remains challenging.
• Existing multi-pinhole configurations often involve trade-offs between imaging resolution and sensitivity, limiting diagnostic accuracy in preclinical studies.
• Mouse cardiac imaging requires high resolution and sensitivity within a small field-of-view to accurately assess cardiovascular function and disease.

Purpose of the Study:

• To develop and evaluate an optimization strategy for multi-pinhole aperture configurations in micro pinhole-SPECT systems.
• To simultaneously improve both spatial resolution and sensitivity for enhanced mouse cardiac imaging.
• To identify an optimal multi-pinhole configuration balancing resolution and sensitivity trade-offs.

Main Methods:

• Analytic models were employed for rapid evaluation of projection areas, sensitivities, and spatial resolutions of various multi-pinhole designs.
• Candidate optimal configurations were identified using preliminary analytic model evaluations.
• System performance was assessed using GATE simulations, generating system matrices (H matrices) for signal-known-exactly/background-known-statistically detection tasks, Fourier crosstalk analysis for spatial resolution, and H matrix calculations for sensitivity.

Main Results:

• A trade-off function incorporating Area Under the ROC Curve (AUC) and spatial resolution was utilized to determine the optimal configuration.
• The optimized configuration features a 22.5° rotated detector, a 4-pinhole aperture with 22.5° rotation, 20% multiplexing, and 1.52X magnification.
• This configuration was validated for a 14 mm field-of-view micro pinhole-SPECT system using a 49 × 49 mm² active area camera.

Conclusions:

• The proposed optimization strategy effectively balances spatial resolution and sensitivity for micro pinhole-SPECT mouse cardiac imaging.
• The identified optimal multi-pinhole configuration significantly enhances imaging performance for preclinical cardiovascular studies.
• This approach provides a robust method for designing advanced SPECT systems tailored to specific small animal imaging applications.