Shortened PET data acquisition protocol for the quantification of 18F-FDG kinetics

Area of Science:

• Nuclear Medicine
• Radiochemistry
• Medical Imaging

Background:

• Positron Emission Tomography (PET) using 2-[18F]fluoro-2-deoxy-D-glucose ((18)F-FDG) is crucial for assessing cellular metabolism.
• Dynamic PET acquisitions provide detailed kinetic parameters but are time-consuming.
• Standardized uptake values (SUVs) are commonly used but offer limited kinetic information.

Purpose of the Study:

• To define and evaluate a modified short dynamic protocol for predicting kinetic parameters of (18)F-FDG metabolism.
• To assess the accuracy of estimating (18)F-FDG influx, vascular fraction (VB), and the rate constant k1 using SUVs derived from a shortened protocol.

Main Methods:

• A modified short dynamic protocol was developed, involving a 1-10 min dynamic acquisition and a 56-60 min static acquisition.
• 151 patient datasets from 60-minute dynamic (18)F-FDG PET scans were analyzed.
• Standardized uptake values (SUVs) were calculated, and a 2-compartment model was applied to determine reference kinetic parameters, including (18)F-FDG influx, VB, and k1.
• Correlation analysis was performed between SUVs and reference parameters; subset analysis identified optimal time intervals for prediction using polynomial functions.

Main Results:

• Significant correlations were found between SUVs and (18)F-FDG influx, VB, and k1.
• Late SUVs correlated with influx, while early SUVs showed higher correlations with VB and k1.
• The defined short dynamic protocol, using early (1-10 min) and late (56-60 min) SUVs, achieved correlation coefficients exceeding 0.9 for predicting influx, VB, and k1 when input (blood) and target area SUVs were utilized.

Conclusions:

• A short dynamic PET acquisition protocol can yield detailed information on (18)F-FDG kinetics.
• (18)F-FDG influx, VB, and k1 can be accurately estimated from SUVs obtained using this optimized short protocol, reducing scan time.