Fast quantitative reconstruction with focusing collimators for liver SPECT

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiotherapy

Background:

• Single-photon emission computed tomography (SPECT) scans can optimize liver radioembolization treatments through image-guided dosimetry.
• Achieving this requires faster acquisition times and rapid quantitative reconstruction methods.
• Focusing collimators enhance SPECT sensitivity, potentially speeding up imaging.

Purpose of the Study:

• Develop a fast Monte Carlo-based reconstruction technique for focusing collimators.
• Evaluate the impact of reconstruction methods and collimator types on quantitative accuracy in liver dosimetry using simulations.

Main Methods:

• Developed a fast Monte Carlo simulator for SPECT projection generation.
• Compared Monte Carlo-based scatter correction with other methods.
• Simulated quantitative accuracy and noise levels for focusing and parallel hole collimators.

Main Results:

• The fast Monte Carlo simulator generated accurate projections in seconds, drastically reducing computation time.
• Monte Carlo scatter correction outperformed other methods, achieving comparable noise levels to dual-energy window correction.
• Focusing collimators with varying focal distances achieved similar quantitative accuracy to parallel hole collimators in significantly less time.

Conclusions:

• Combining focusing collimators with Monte Carlo reconstruction enables faster quantitative SPECT imaging.
• The proposed forward projector approach allows reconstruction within minutes.
• These advancements are vital for enabling real-time dosimetry during interventions.