The ability to perform cell tracking using x-ray computed tomography combined with gold nanoparticles has been demonstrated recently on ex vivo samples using different malignant and nonmalignant cell lines. Here we proved the concept of the method for in vivo assessment in a small-animal model of malignant brain tumors. The limitations of the method due to radiation dose constraints were investigated using Monte Carlo simulations. Taking into consideration different x-ray entrance doses and the spatial resolution, the visibility of the cell clusters was evaluated. The results of the experiments conducted on mice implanted with F98 tumor cells confirmed the prediction of the Monte Carlo calculations. Small clusters of cells exogenously loaded with gold nanoparticles could be visualized using our in vivo method.
