Inclusion Criteria: Total enrollment for all groups will not exceed 100 subjects.
* Group 1: Healthy subjects
* Age greater than 18 years
* Be deemed healthy at screening visit as determined by the physician investigator or nurse practitioner, based on the following assessments at Screening: physical examination, medical history, and vital signs
* Have the ability to give written informed consent;
* No known history of pulmonary disease (excluding pulmonary nodules);
* No prior history of tobacco use.
Group 2: Lung cancer subjects
* Eligible patients will be those harboring locally advanced clinical stage IIIA NSCLC who are deemed candidates for multi-modality therapy, i.e. concurrent chemotherapy and radiation followed by pulmonary resection.
* Age greater than 18 years
* Have the ability to give written informed consent.
* No tobacco use within the prior 6 months.
Group 3: Subjects with pulmonary fibrosis
* IPF (with a UIP or probable UIP pattern); or other forms of interstitial lung disease (ILD), including CTD-ILD, with a fibrotic component as noted by the presence of reticular markings and / or traction bronchiectasis and / or honeycombing on CT;
* Age: 40-80 years old;
* Have the ability to give written informed consent;
* No tobacco use within the prior 6 months
Group 4: Subjects with chronic lung allograft dysfunction (CLAD)
* Status post lung transplantation
* Clinical diagnosis of chronic lung allograft dysfunction
* Age: 40-80 years old;
* Have the ability to give written informed consent;
* No tobacco use within the prior 6 months
Group 5: Subjects with immune-checkpoint-inhibitor (ICI) pneumonitis
* CT findings with ground glass opacities / consolidation or fibrotic changes with new onset during or within 3 months of receipt of ICI therapy
* Age greater than 18 years
* Have the ability to give written informed consent
* No tobacco use within the prior 6 months
Exclusion Criteria:
* Electrical implants such as cardiac pacemaker or perfusion pump;
* Ferromagnetic implants such as aneurysm clips, surgical clips, prostheses, artificial hearts, valves with steel parts, metal fragments, shrapnel, metallic tattoos anywhere on the body, tattoos near the eye, or steel implants ferromagnetic objects such as jewelry or metal clips in clothing;
* eGFR of less than 30 mL/min/1.73 m2 within the past 90 days for group 4 subjects; history of chronic kidney disease for subjects in groups 1-3 and 5;
* Pregnant or breastfeeding (a negative quantitative serum hCG pregnancy test is required for females having child-bearing potential before the subject can participate);
* Claustrophobic reactions;
* Research-related radiation exposure exceeds current Radiology Department guidelines (i.e. 50 mSv in the prior 12 months);
* Unable to lie comfortably on a bed inside the MR-PET;
* BMI \> 33 (limit of the MRI table);
* Determined by the investigator(s) to be clinically unsuitable for the study (e.g. based on screening visit and/or during study procedures);
* Known history of pulmonary disease (except for pulmonary fibrosis in the study group, ICI pneumonitis in the study group, or CLAD in the study group), recent pneumonia or respiratory tract infections within 6 weeks of enrollment, prior radiation therapy to the thorax (except for the lung cancer patients in aim 2);
* Pneumonia or other acute respiratory illness within 6 weeks of study entry (except for pulmonary fibrosis), pneumonia defined with elevated WBC, fever, infiltrate on CXR and need for antibiotics
