Acoustic detection of physiological change within the thorax

This paper presents the initial results of the development of a non-invasive, in vivo method for the detection of physiological changes within the thorax. An acoustic method is used; where, by generating a variable frequency acoustic in the mouth, the natural structure of the airways may be utilised to detect lung abnormalities at the surface of the thorax. The development of this method considers both theoretical and physical models of the system alongside measurements taken from a number of subjects. Using this method has produced results from five subjects suggesting that transmission is effected by physiological differences between subjects and that the useful frequency range is limited, due to the absorption of the acoustic signal by the body, to frequencies of up to a few hundred hertz