68Ga

68Ga-DOTATOC (Gallium (68Ga) edotreotide injection) and related tracers

Gallium-68 is a positron-emitting isotope (t1/2 68 minutes) which is generated from Germanium-68 in Gallium-68 generators, for use in PET.

The development of novel PET tracers which specifically bind to somatostatin receptors (SSTR2-5) permits the visualization of neuroendocrine tumors with higher sensitivity than other imaging procedures. Among these tracers, 68Gallium-DOTA-peptides are increasingly being used for diagnosis and therapy monitoring.  Another growing application of Gallium-68 is the targeting of the Prostate-specific membrane antigen (PSMA) overexpression in order to image prostate cancer (PCa) metastases 

The principal tests for 68Ga-DOTATOC and related 68Ga tracers are:

Test

Technic/instrument

Appearance

Visual

Radionuclidic Identity

Gamma-ray spectroscopy with Multichannel analyser

Radionuclidic Identity

Half-life determination with a dose calibrator

pH

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

Chemical purity

Gradient HPLC with UV detector

2-[4-(2-hydroxyethyl)piperazin-1-yl)ethanesulfonic      

   acid (HEPES) test     

Spot test

Ethanol

Gas chromatography

Bacterial endotoxins (LAL)

Endosafe Portable Test System (PTS)

Other radiochemical impurities

Radio-HPLC

Radiochemical purity (68Ga ion)

Radio-TLC

Radiochemical identity

Radio-HPLC

Osmolality

Osmometer

Radionuclidic purity and Germanium-68 impurity

Gamma-ray spectroscopy with Multichannel analyser

Sterility

Compendial method

Radioactivity

Dose calibrator