A physiological monitoring system may perform an optical measurement of a subject to assist a photoacoustic analysis of the subject. For example, an oblique-incidence diffuse reflectance measurement, photon density wave measurement, or other optical measurement may be used to determine one or more optical properties of a subject. Accordingly, the one or more optical properties may be used to determine an optical fluence at a region of the subject. In some arrangements, a physiological monitoring system may include an oximeter, and may use a calculated blood oxygen saturation value to assist a photoacoustic analysis. Photoacoustic analysis may include determining one or more physiological parameters based on a detected acoustic pressure response of a subject to a photonic signal via the photoacoustic effect.
