Quantitative differences in [(18)F] NaF PET/CT: TOF versus non-TOF measurements

Area of Science:

• Nuclear Medicine
• Radiopharmaceuticals
• Medical Imaging

Background:

• [(18)F] sodium fluoride (NaF) PET/CT is a key method for detecting bone metastases.
• Time-of-flight (TOF) PET enhances image quality by reducing noise and improving resolution.
• Quantitative accuracy in standardized uptake value (SUV) measurements is crucial for treatment response assessment.

Purpose of the Study:

• To quantify and compare SUV differences between TOF and non-TOF [18F] NaF PET/CT reconstructions.
• To evaluate the impact of TOF on SUV measurements in various tissues and pathologies.
• To assess the clinical relevance of these quantitative differences in prostate cancer imaging.

Main Methods:

• 47 prostate cancer patients underwent [18F] NaF PET/CT scans.
• SUVmean and SUVmax were measured in normal soft tissues, osseous structures, degenerative changes, and metastases.
• TOF and non-TOF reconstructions were compared using paired t-tests and linear correlations.

Main Results:

• TOF reconstructions yielded higher SUVmean in all osseous structures (normal, degenerative, metastatic) compared to non-TOF.
• TOF showed lower SUVmean in normal soft tissues like liver, brain, and adipose tissue.
• Average SUVmean increased by 2.5% in metastases and 3.5% in degenerative joint disease with TOF, especially in smaller lesions.

Conclusions:

• TOF [18F] NaF PET/CT provides higher SUV values in bone lesions and normal bone, and lower values in soft tissue background.
• While statistically significant, the magnitude of SUV differences between TOF and non-TOF is modest.
• Consideration of TOF vs. non-TOF reconstruction differences is essential for accurate therapy response evaluation and multi-center trial design.