Quantitative accuracy in total-body imaging using the uEXPLORER PET/CT scanner

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiochemistry

Background:

• Absolute quantification of radioactivity in Positron Emission Tomography (PET) is crucial for clinical and research applications.
• Accurate quantification is influenced by scanner calibration, data corrections, and image reconstruction.
• Long axial field-of-view (FOV) PET systems offer expanded dynamic range but present quantification challenges.

Purpose of the Study:

• To comprehensively evaluate the quantitative accuracy of the uEXPLORER total-body PET scanner.
• To assess performance across various imaging conditions, including dynamic and ultralow-dose protocols.
• To validate the scanner's suitability for diverse clinical and research applications.

Main Methods:

• Utilized total-body specific phantom and human measurements for evaluation.
• Employed the NEMA NU 2-2018 protocol for relative count rate accuracy assessment.
• Analyzed axial uniformity, activity bias in phantoms, and region/volume-of-interest quantification in human subjects.

Main Results:

• Achieved ±3%-4% relative count rate accuracy and ±3% axial uniformity across the central 90% FOV.
• Demonstrated a 3% activity bias spread in a long phantom and 1% quantification spread across multiple phantoms.
• Observed -2% to +1% activity bias in human subjects, with challenges during bolus injection phases.

Conclusions:

• The uEXPLORER scanner exhibits uniform quantitative performance across its entire axial FOV.
• The system provides the necessary accuracy for a wide spectrum of PET imaging applications.
• Further research may be needed to address data correction complexities in dynamic human imaging scenarios.