Canada's leading nuclear medicine company is gearing up for the restart of Atomic Energy of Canada's aging reactor in Chalk River, Ont.

MDS Nordion, which now forms the core of Canadian life-science company MDS Inc. (TSX:MDS), says it has a new contract with its primary customer.

Nordion will supply Lantheus Medical Imaging with material used to create a key medical isotope — once the NRU reactor resumes operations.

The reactor is expected to be back in operation by the end of this month, after more than a year of unscheduled downtime for repairs.

Nordion is a leading global supplier of radioactive materials used for medical imaging procedures around the world.

The Ottawa-based company will supply Lantheus with Mo-99, which is processed to create an isotope used in about 80 per cent of nuclear medicine procedures.

Nordion will supply Lantheus on a weekly basis until July 31, 2011 — once AECL's reactor goes back into service.

"Lantheus and MDS Nordion have a long history of working together and this contract further demonstrates our commitment to provide medical isotopes to the global nuclear medicine community," said Lantheus president and CEO Don Kiepert in a statement issued Thursday by MDS.

Financial terms of the supply agreement weren't disclosed.