We review a digital X-ray imaging technique which permits in situ 2D imaging of the crucible interior during physical vapor transport growth of SiC. In addition, we use 13 C-labeling experiments to determine the mass transport paths in the growth cell interior. The combination of both experimental techniques enabled the analysis of the global SiC growth process like determination of growth rate, quantitative analysis of the evolution of the source material morphology, interaction of Si- and C-containing gas species with the graphite crucible wall, etc. The data will be used for comparison with numerical modeling of the SiC growth process including calculation of temperature field, mass transport and changes of the source material morphology, i.e. porosity and graphitization. In addition to the application of X-ray imaging for fundamental growth studies, monitoring of routine growth runs will also be pointed out.