TORONTO - MDS Inc said on Friday that it planned to buy back more than 40 percent of its outstanding shares as the Canadian company advances its plans to narrow its focus to nuclear imaging.

The Toronto-based company, which announced its intention to conduct the substantial share buyback earlier this month, said it would cancel between 40 percent and 46 percent of its shares worth up to $450 million.

MDS plans to buy back the shares at $8.10 to $9.30 each in a modified Dutch auction.

The company's shares closed at $8.10 on the New York Stock Exchange on Thursday. ($1=$1.05 Canadian) (Reporting by Scott Anderson; Editing by Lisa Von Ahn)