6.2 Producing the radioactive substance (elution)
In the radiopharmacy Tc-99m is produced in a generator.
Mo-99, a product of the fission of uranium, is isolated from a nuclear reactor and absorbed on to an alumina column in the generator. When a saline solution is passed over the column, ion exchange results in the production of sodium pertechnetate. This can then be chemically manipulated to form a variety of compounds. The removal of the technetium by the passage of saline is known as elution.
Conveniently, the optimum interval between elutions is 24 hours. As the half-life of Mo-99 is 66 hours the generator itself can be used for approximately one week. It is then returned to the supplier and replaced with a new one.
Click on the video clip to watch the elution process. Why do you think protective clothing needs to be worn?
Click to view part 1 of the clip about radionuclide imaging [2 minutes 26 seconds]
Transcript: Radionuclide Introduction
The pharmaceutical will be injected directly into the patient, so it must be produced in completely sterile conditions. The suit and mask are worn to prevent germs from the person reaching the eluate.