Radiation therapy products developer North American Scientific Inc. said Tuesday that the U.S Food and Drug Administration has approved a high-dose radiation version of its ClearPath breast cancer treatment.

The FDA approval for Chatsworth-based company’s breast brachytherapy product follows approval of a low-dose version of the treatment in April. Brachytherapy uses radioactive seeds placed through the breast using needles or catheters.

North American Scientific shares rose 8 percent to $1.19. The company estimates that accelerated partial breast irradiation treatments are a potential $500 million market in the United States.

Company founder Michael Cutrer announced earlier this month that he was resigning as chief executive but would stay on at the company with the title of chief technology officer. He will remain on the board of directors.