RT Journal Article SR Electronic T1 PDT in early central lung cancer JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 374 OP 375 DO 10.1136/thx.2006.067892 VO 62 IS 5 A1 Lutz Freitag YR 2007 UL http://thorax.bmj.com/content/62/5/374.abstract AB