In vitro 2-deoxy-2-[18F]fluoro-D-glucose uptake: practical considerations

Area of Science:

• Nuclear medicine
• Oncology
• Cell biology

Background:

• 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]-FDG) is a widely used positron emission tomography (PET) tracer in oncology.
• Limitations of [(18)F]-FDG PET include low tumor metabolic activity and high physiological uptake in surrounding tissues.
• In vitro studies offer a cost-effective alternative to animal experiments or clinical trials for investigating tracer behavior.

Purpose of the Study:

• To investigate the influence of various experimental parameters on [(18)F]-FDG uptake in vitro.
• To analyze the impact of incubation time, cell medium, administered activity, and cell density on tracer uptake.
• To correlate [(18)F]-FDG uptake with Glucose transporter 1 (GLUT1) and Hexokinase 2 (HK2) expression.

Main Methods:

• Six different cell cultures were used for in vitro experiments.
• [(18)F]-FDG uptake was measured under varying conditions: incubation time, glucose presence/absence in medium, administered activity, and cell density.
• Immunocytochemistry was employed to assess GLUT1 and HK2 expression at different cell densities.

Main Results:

• [(18)F]-FDG uptake increased with incubation time and in the absence of glucose in the medium.
• Higher administered activity led to increased uptake per protein.
• Tracer uptake per protein was lower at higher cell densities, correlating with reduced GLUT1 and HK2 expression.

Conclusions:

• Incubation time, glucose availability, administered activity, and cell density significantly influence [(18)F]-FDG uptake in vitro.
• Maintaining constant experimental conditions (activity, medium, time) is crucial for reproducible results.
• Cell density-dependent variations in tracer uptake necessitate appropriate corrections, especially in therapeutic contexts.