Study on localized thermal expansion gradient formation for acoustic wave generation in a novel thermoacoustic imaging modality
Bardhan Roy, Rupak (2017) Study on localized thermal expansion gradient formation for acoustic wave generation in a novel thermoacoustic imaging modality. [Thesis]
Thermoacoustics is the process of generation of sound by heat or vice versa. Volume generated thermoacoustic signals can be produced by thermal expansion induced volume contraction and rarefaction inside a target body. Thermoacoustic imaging uses this modality to obtain vivid insight into the internal structure of target body, both for non-destructive testing and biomedical imaging. Any penetrating pulsed radiation can be used for such purpose, including microwave where the modality is called thermoacoustics in general or by incident light waves where the same is termed as photoacoustics. The current thesis establishes the theoretical basis for a novel thermoacoustic imaging modality where pulsed ultrasound is used as the incident penetraing source. A formal forward transient theoretical eqution set is derived based on established transient acoustic propagation models and the problem is solved using a commercially available FEM software. The results are then compared with experimental results and considerable agreement has been observed.
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