North American Scientific Inc. sold off its radiation oncology business to privately-held Best Medical International Inc., the company announced. The deal was worth approximately $3.6 million. The sale is a milestone in North American’s strategy to build shareholder value by focusing on its core brachytherapy business, said President and CEO John Rush. “Our goal is to increase our participation in the growing breast and prostate cancer markets, which we believe represent a total U.S. addressable market opportunity of more than $800 million,” Rush said. Springfield, Va.-based Best Medical is expected to continue operation of the radiation oncology business and to invest in the development of next-generation products.