A method of adjusting SUV for injection-acquisition time differences in (18)F-FDG PET imaging

Area of Science:

• Nuclear Medicine
• Oncology
• Medical Imaging

Background:

• Standardized uptake values (SUVs) in (18)F-FDG PET imaging are crucial for lung cancer assessment.
• Variability in SUV measurements due to time differences after injection can affect diagnostic accuracy.
• Accurate SUV quantification is essential for monitoring treatment response and disease progression.

Purpose of the Study:

• To propose and validate a time normalization method for tumor SUVs in (18)F-FDG PET imaging.
• To assess the impact of time differences on SUV measurements in lung cancer patients.
• To establish a reliable method for standardizing SUV values across different scan times.

Main Methods:

• Utilized a two-compartment model analysis to evaluate SUV variations.
• Compared SUV measurements (corrected and uncorrected for (18)F physical decay) from two PET acquisitions within a 55-110 minute post-injection window.
• Assessed maximal SUV of malignant lesions in 10 lung cancer patients.

Main Results:

• Uncorrected SUVs showed no significant difference between the two acquisitions.
• Corrected SUVs exhibited significant differences, indicating the need for normalization.
• A simple normalization formula, SUV(N) = 1.66 SUV(uncorr), was derived based on decay correction at 79 minutes.

Conclusions:

• A straightforward SUV normalization for time differences is effective in (18)F-FDG PET imaging of lung cancer patients.
• This method is validated for scans performed between 55 and 110 minutes post-injection.
• The proposed normalization achieves a relative measurement uncertainty of ±2.5%.