Norton Healthcare officials say they hope to begin construction in September on a nearly $10 million cancer radiation center at its downtown campus.The center is one of three radiation centers in Louisville approved this week by the state Certificate of Need Office.The others will be built on La Grange Road by Baptist Hospital East, and on Old Henry Road by a local physician's group.The Norton facility will be constructed at Floyd Street and Broadway. Company Executive Vice-President Russ Cox says it will contain a $3 million linear accelarator used to destroy cancer cells."This piece of equipment is only in 17 communities right now. It's a very specific way of delivering radiation therapy that is very sparing to other tissue around the cancer. It also can get very specific with tumors that are deeply embedded," Cox said.Norton plans to tear down two buildings at Floyd and Broadway to make room for the new facility.