An approach based on acoustics and its theoretical analogies to electromagnetism is used in the present research to study the detection of the acoustic wave energy radiated by the thermal random motion of material particles of the brain during activation or caused by pathology. Pressure and particle velocity are calculated in analytical mathematical forms for the case of human brain monitoring, which can be implemented by a prototype passive acoustic brain monitoring system (PABMOS). Representing theoretically the configuration of this approach, a sphere is used to model the human head and an internal point source in order to simulate potential pressure alterations due to intracranial abnormalities or local functional activations. Finally, numerical results concerning the particle velocity (pressure field distribution) at the surface of the head model, which can implicitly be measured by the suitable piezoelectric sensors of the system, for arbitrary positions of the internal source, are presented.
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