Part A of this study aims to validate and compare the different analysis methods. Pulmonary sarcoidosis is a disease characterised by widespread lung inflammation. In Part A of the study the investigators will recruit patients with this condition, as well as age and gender matched (wherever possible) healthy volunteers. All Part A participants will receive one dynamic 18F-FDG PET/CT scan. The investigators will assess the uptake of 18FDG from PET images from patients with sarcoidosis versus those taken from healthy volunteers to validate and assess the reliability of the analysis method.