High-activity ⁹⁹Mo microresin fabrication for submillimeter SPECT system matrix acquisition

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Preclinical Research

Background:

• Single-photon emission computed tomography (SPECT) is crucial for preclinical molecular imaging.
• Accurate system matrices are essential for high-quality SPECT image reconstruction.
• Current methods using ⁹⁹mTc have limitations due to its short half-life, complicating long acquisitions.

Purpose of the Study:

• To develop a generator-producible hybrid ⁹⁹Mo/⁹⁹ᵐTc point source for improved SPECT system-matrix calibration.
• To overcome the limitations of short-lived ⁹⁹mTc for extended acquisition times.
• To facilitate accurate and reproducible calibration for high-resolution SPECT systems.

Main Methods:

• Created a hybrid ⁹⁹Mo/⁹⁹ᵐTc point source using ⁹⁹Mo adsorbed onto AG1-X8 resin microspheres.
• Achieved high activity per bead (>10 mCi).
• Conducted Monte Carlo simulations on two SPECT platforms to assess ⁹⁹Mo contamination impact.

Main Results:

• The hybrid source provides high activity with an effectively longer usable half-life.
• Monte Carlo simulations showed negligible impact of ⁹⁹Mo high-energy photons on ⁹⁹mTc system-matrix measurements.
• The source strength was sufficient for a 100×100×100 system-matrix acquisition.

Conclusions:

• Introduced a practical method for accurate, reproducible system-matrix calibration in state-of-art SPECT.
• The hybrid ⁹⁹Mo/⁹⁹ᵐTc source supports the development of high-resolution SPECT systems.
• Ensures consistent imaging performance through reliable calibration.