Abstract
AbstractA novel embedded photoacoustic system design is described and a calculation method is proposed to determine the blood hemoglobin oxygen saturation through the thermal properties of different skin color types. A heat equation model allows a calculation procedure to determine the reflection and transmitted thermal wave amplitude for obtaining a depth profile, depending on the modulation frequency at the air-skin-subcutaneous tissue interface. Our reflection-mode photoacoustic technique involves the use of a 445 nm pulsed-laser light spot on subcutaneous tissue to obtain amplitude and phase from signals for different skin color types. The transmission and reflection temperature coefficients are fitted through a heat propagation model to estimate the thermal wave properties of blood hemoglobin. Nonlinearly amplified photoacoustic signals are modeled from the microphone and their stability analyzed by a bode diagram, as to consider overheated hemoglobin background. An dedicated electronic embedded system is thus integrated, including memory, processor and preprocessor, to provide a simple measurement technique, as compared to conventional instruments.
Publisher
Springer Science and Business Media LLC