To implement a new method of performing chest CT imaging in young children at Packard Children's Hospital entitled controlled ventilation infant/young child chest CT scanning. This technique will be used to evaluate early lung disease comparing quantitative chest CT air trapping and airway measurements with lung function measurements in infants, toddlers, and young children with chronic lung disease.

Inclusion Criteria:1) Infants and young children (age <= 3 months to < 5 years) and either 2) or 3) below.

2) Respiratory condition (e.g. cystic fibrosis (CF), primary ciliary dyskinesia, bronchopulmonary dysplasia, asthma, or other pulmonary condition) and under the care of a pediatric pulmonologist at LPCH.

3) Oncology condition (e.g. young children with or without cancer, who are being screened for lung metastasis) and are being followed by pediatric oncologists at LPCH.

4) For minors, informed consent by parent or legal guardian.

5) Ability to comply with study visit procedures as judged by the investigator. Exclusion Criteria:1) Acute wheezing and/or respiratory distress at Study visit.

2) Acute intercurrent respiratory infection, defined as an increase in cough, wheezing, or respiratory rate with onset in 1 week preceding Study visit.

3) Oxygen saturation < 90% on room air at study visit.

4) Any medical condition that in the opinion of the investigator precludes subject participation.

infants/young children with cystic fibrosis, primary ciliary dyskinesia, or other chronic lung disease, followed at our CF Center or Pulmonary Clinics