regional lung density ( dl ) and regional fractional pulmonary blood volume ( vb ) were measured quantitatively during tidal breathing in 30 healthy supine subjects ( 15 smokers and 15 nonsmokers ) in a 1.7-cm-thick midthoracic cross section using positron emission tomography ( pet ) and 11co ( inhaled ) -labeled erythrocytes .
C0035203
breathing
C0004048
inhaled