Take a nice, deep breath. Now imagine your lungs: myriad airways like branches, each with tiny alveoli like leaves. This alveolar structure is key to the absorption of oxygen and excretion of carbon dioxide that we call "breath." As we breathe, the volume of gases in the lungs is continually changing with varying degrees of inhalation and exhalation. These volumes are medically important for clinical assessment and diagnosis of respiratory pathologies.
A light-based technology known as gas-in-scattering-media absorption spectroscopy (GASMAS) may allow noninvasive optical sensing of respiratory volumes. Using tuneable diode laser spectroscopy, GASMAS turns optical signals into information for measuring gas concentration. Reference models, known as "phantoms," afford relevant features that help biomedical optics researchers to identify technical challenges and potential applications of GASMAS technology.
As reported in the Journal of Biomedical Optics, scientists at Tyndall National Institute (TNI) in Ireland recently developed a lung phantom that mimics the optical properties and structure of the lung, including the tiny alveoli. The complexity of alveolar anatomy has meant that previous state-of-the-art lung phantoms have neglected it. The work done with this novel lung phantom demonstrates the feasibility of GASMAS to sense changes in gas volume in a controlled environment mimicking lung tissue.
