Using digital X-ray imaging we have investigated the on-going processes during physical vapor transport growth of SiC. A high-resolution and high-speed X-ray detector based on image plates and digital recording has been used to monitor SiC bulk crystal growth as well as SiC source material degradation on-line during growth. We have analyzed the shape of the growth interface and the evolution of the SIC source morphology. The crystal growth process will be discussed in terms of growth rate and limitations of the physical vapor transport of SIC gas species from the source to the growth interface,