Improved dead-time correction for PET scanners: application to small-animal PET

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Instrumentation

Background:

• Positron Emission Tomography (PET) scanners exhibit nonlinear responses due to pile-up and dead-time effects.
• These effects are influenced by object characteristics and activity distribution, complicating accurate corrections.
• Existing methods struggle with broad applicability across different acquisition scenarios.

Purpose of the Study:

• To develop a robust and accurate method for correcting PET scanner nonlinearity.
• To address the limitations of current correction techniques for pile-up and dead-time.
• To establish a correction method valid across diverse scanner geometries and activity levels.

Main Methods:

• Demonstrated a linear relationship between singles-to-coincidences ratio (SCR) and effective dead-time.
• Proposed a novel correction method utilizing two calibration acquisitions with varying SCR.
• Validated the method through simulations and experimental data on two distinct PET scanner configurations.

Main Results:

• The proposed SCR-based correction method accurately estimates dead-time and pile-up effects.
• Achieved accuracy within 7% even at high activity concentrations within the field of view.
• The method demonstrated superiority over standard single-parameter correction techniques, avoiding bias.

Conclusions:

• A simple and accurate method for PET scanner nonlinearity correction has been developed.
• The SCR-based approach offers improved performance and broader applicability compared to existing methods.
• This technique enhances the reliability of quantitative PET imaging, particularly in high-activity scenarios.