RT Journal Article SR Electronic T1 Disease activity in COPD: time to make imaging biomarkers a PET project? JF ERJ Open Research JO erjor FD European Respiratory Society SP 00445-2021 DO 10.1183/23120541.00445-2021 VO 7 IS 3 A1 Stephen Milne A1 Rachel L. Eddy A1 Don D. Sin YR 2021 UL http://openres.ersjournals.com/content/7/3/00445-2021.abstract AB