The following is a non-comprehensive illustration of an encoding of Photoacoustic data captured with a coupled conventional ultrasound system in either handheld or stationary acquisition mode. At each of M Temporal Positions, N optical excitation wavelengths are applied in rapid succession and Photoacoustic Images are acquired for each wavelength (in this example, N=2). Ultrasound images are also acquired however the timing of the ultrasound acquisition is not synchronized with the Photoacoustic wavelength temporal position boundaries; it is left to the implementation to determine which ultrasound frames belong with each Temporal Position Time Offset. In this example, the Photoacoustic device knows the spatial relationship of its image data relative to the Ultrasound device and can use the Registration SOP Class to specify the relationship of the images from the two modalities.