Ultrasound transit time spectroscopy in complex media: Applications and relationship with phase interference

Osteoporosis is a common disease affecting 60% of women and 30% of men over 50 years. Quantitative ultrasound is a reliable technique for the bone assessment and predicting fracture risk. Lack of knowledge about ultrasound propagation affects the ability of accurate determination of bone mass and structure. A new proposed hypothesis is that phase interference is the leading attenuation mechanism in complex composite due to inhomogeneity transit time of the sonic rays. It also proposed that the propagation of ultrasound wave can be approximated as parallel sonic rays; each has a transit time determined by the proportion of bone (solid) and marrow (liquid) it travels through. Therefore, this thesis illustrated a development and validation of an ultrasound transit time model of complex structure and identify its relation with phase interference. This study will further explore possible applications of the TTS to enhance the effectiveness of ultrasound as a reliable bone assessment tool.