Is my chemo working? Scans may give faster answer

Denis Poroy/AP

Lung cancer patient Mike Stevens poses in his La Jolla, Calif. home Monday, March 2, 2009. When Stevens, 48, learned his lungs were riddled with cancer, it took only a week to start chemotherapy-but six weeks to find out if it was doing any good. New types of PET scans may answer that agonizing question in days, instead of weeks.