<qa>  What is the minimum age of subjects to be excluded from the bronchoscopy?No subjects will be excluded based on race or gender. Subjects must be between 18 and 50 in order to avoid greater risks of bronchoscopy and, in those under 18, exposure to radiation. To avoid risks, women will not be enrolled if pregnant, lactating or of childbearing potential and unwilling to undertake appropriate precautions. 