Novel probe based optical techniques such as Confocal laser endomicroscopy (pCLE) and Optical coherence tomography (pOCT) are non-invasive optical techniques, compatible with conventional diagnostic bronchoscopes and provide non-invasive, real-time information on the airway wall and the alveolar compartment. Therefore, immediate validation of optical measurements during a biopsy is possible. Optical techniques might either obviate the need for an tissue biopsy or improve the diagnostic yield of conventional biopsy methods and make surgical lung biopsies that are associated with high morbidity and costs redundant.