18F-FDG

18F-FDG (Fluodeoxyglucose-18F injection)

[18F]FDG has become a common imaging modality in oncology. [18F]FDG is an analogue of glucose that contains the radionuclide Fluorine-18.  This radiotracer provides valuable functional information based on the increased glucose uptake and glycolysis of cancer cells. 

Fluorine-18 decays by positron (β+) emission and has a physical half-life of 109.7 minutes. 

The quality requirements of [18F]FDG are set out in various pharmacopoeia including the USP, BP, EP… 

Although there are some differences among these references, the philosophy and key analysis are similar and require the same analytical equipment. 

The principal tests for 18F-FDG are:

Test

Technique / instrument

Appearance

Visual

Radionuclidic Identity

Gamma-ray spectroscopy with a multichannel analyser (MUCHA)

Radionuclidic Identity

Half-life determination with a dose calibrator or alternative detector

pH

pH-meter or pH strips with reading through a reflexion photometer

Chemical purity (Chloro-DG, FDG)

Isocratic HPLC with a carbohydrate detector (PAD or RID) and a He purge

Impurity kryptofix 222 (aminopolyether)     

Spot test (camera)

Residual solvents (EtOH, CH3CN)

Gas chromatography

Bacterial endotoxins (LAL)

Endosafe Portable Test System (nexgen PTS)

Radiochemical purity

Radio-HPLC

Radiochemical purity

Radio-TLC

Radiochemical identity

Radio-HPLC

Osmolality ("not compulsory")

Osmometer

Radionuclidic purity

Gamma-ray spectroscopy with a multichannel analyser (MUCHA)

Sterility

Compendial method

Radioactivity, volumic activity

Dose calibrator