The U.S. Federal Trade Commission terminated the waiting period for the acquisition under the Hart-Scott-Rodino Antitrust Improvements Act, Nordion said in a statement.

The company said in June it had received a request for additional information from the U.S. regulator.

Nordion also said on Friday that it received a no-action letter from the Canadian Competition Bureau.

The deal is expected to close in the second half of this year.

Nordion is a leading producer of molybdenum-99, an isotope used in medical imaging, while Sterigenics is a sterilization services provider owned by private equity firm GTCR LLC.

Nordion's U.S.-listed shares were up 3 percent at $12.80 in premarket trading.

(Reporting by Ashutosh Pandey in Bangalore; Editing by Kirti Pandey)