A synchrotron-based experiment was carried out to demonstrate the potential of x-ray photon correlation spectroscopy (XPCS) to characterize collective dynamics driven by superparamagnetic iron oxide nanoparticles (SPIONs) during magnetomotive ultrasound (MMUS) imaging. MMUS is a developing diagnostic imaging technique that has the potential to enable more precise cancer staging than other clinically established diagnostic tools. It relies on SPIONs acting as a contrast agent while being stimulated by time-varying magnetic fields. The resulting dynamics are crucial to maximizing image contrast. We describe the design and execution of an XPCS experiment on phantoms mimicking human tissue during MMUS imaging. Quantitative analysis of the results reveals variations in the temporal correlation functions of the scattered intensity as a function of scattering vector and angle. Preliminary observations indicate that these variations might depend on experimental parameters such as the frequency and strength of the magnetic field and SPION type and concentration