  Photo-acoustic tomography (PAT) aims to leverage the photo-acoustic coupling
between optical absorption of light sources and ultrasound (US) emission to
obtain high contrast reconstructions of optical parameters with the high
resolution of sonic waves. Quantitative PAT often involves a two-step
procedure: first the map of sonic emission is reconstructed from US boundary
measurements; and second optical properties of biological tissues are
evaluated. We consider here a practical measurement setting in which such a
separation does not apply. We assume that the optical source and an array of
ultrasonic transducers are mounted on a rotating frame (in two or three
dimensions) so that the light source rotates at the same time as the US
measurements are acquired. As a consequence, we no longer have the option to
reconstruct a map of sonic emission corresponding to a given optical
illumination. We propose here a framework where the two steps are combined into
one and an absorption map is directly reconstructed from the available
ultrasound measurements.
