Validation of the Analysis Methodology Behind the Use of Quantitative 18F-FDG PET/CT to Assess Lung Inflammation

The purpose of this study is to validate the method of analysing Positron Emission Tomography (PET) images to assess lung inflammation. Development of novel therapeutic drugs requires a biomarker which is sensitive to the underlying disease and can respond to therapeutic interventions. PET is a potential imaging biomarker which can target molecular and cellular processes. There is currently no standardised method of analysing PET lung data and a lack of validation for the existing techniques. This study is divided in to two parts. Part A aims to determine the best method to perform 18F-FDG PET/CT lung analysis and how it correlates with cell counts from bronchoalveolar lavage (BAL) samples taken from participants with active pulmonary sarcoidosis. Part B will compare imaging data from healthy volunteers who have either undergone a Lipopolysaccharide (LPS) challenge (whereby the lung is temporarily inflamed) or saline equivalent to determine whether lung inflammation can be detected by 18F-FDG PET/CT. No medications will be given and patients will not be asked to stop or change existing medication.