The requirements set for particle accelerators for production
of radioactive isotopes for PET can easily be derived from first
principles. The simple general need is for proton beams with
energy in the region 10–20 MeV and current 20–100 microAmps.
This is most reliably and cost-effectively achieved by the well
proven technology of the compact medical cyclotron, presently
available from several companies. The main features of these
cyclotrons are essential similar: resistive, sector focused iron
magnets, internal negative ion sources and stripping extraction.
The remaining differences between different manufacturers will
be discussed the light of what is actually needed for a given
PET site operation.
Alternatives to the conventional cyclotron have been proposed
and tested but have at present very limited use. These alternatives
will be discussed, as well as the future possibilities of
supplying point of demand tracer production with very small
cyclotrons of energy well below 10 MeV.
The authors best advice at present for new PET sites is to negotiate
for conventional cyclotron solutions from experienced
manufacturers. It is the combined performance of cyclotron
and target in terms of available activity output and the specific
activity that is the real figures of merit and it is recommended
that cyclotron solutions are weighted according to this and that
acceptance tests are set up to realistically evaluate the routine
availability of this output.