Imaging pulmonary inducible nitric oxide synthase expression with PET

Area of Science:

• Nuclear medicine
• Molecular imaging
• Pulmonary medicine

Background:

• Inducible nitric oxide synthase (iNOS) activity elevates in inflammatory lung conditions.
• Imaging iNOS expression offers potential as an inflammation biomarker for disease monitoring.

Purpose of the Study:

• To evaluate the novel positron emission tomography (PET) tracer (18)F-NOS for quantifying iNOS expression in endotoxin-induced acute lung inflammation in healthy volunteers.

Main Methods:

• Healthy volunteers underwent baseline and post-endotoxin (18)F-NOS PET/CT scans.
• Lung inflammation was induced bronchoscopically with endotoxin.
• iNOS expression was assessed by (18)F-NOS uptake (distribution volume ratio) and immunohistochemical staining of bronchoalveolar lavage cells.

Main Results:

• A ~30% increase in (18)F-NOS uptake (DVR) was observed in the inflamed lung region.
• Increased uptake correlated with positive iNOS staining in bronchoalveolar lavage cells.
• No significant change in uptake was noted in the contralateral lung.

Conclusions:

• The (18)F-NOS PET tracer effectively images iNOS activity in human acute lung inflammation.
• (18)F-NOS shows promise as a PET imaging biomarker for inflammatory lung diseases.