PET can detect dynamic changes of key proteins in the pathophysiological process of pulmonary fibrosis, for example, type I collagen, of which the deposition is a hallmark of idiopathic pulmonary fibrosis [87], and αvβ6, a kind of arginine-glycine-aspartic acid (RGD)-integrin involved in the pathogenesis of pulmonary fibrosis by activating transforming growth factor β (TGFβ) [88]. The gene discussed is TGFB1; the disease is pulmonary fibrosis.