Fig. 1. Comparison with the results of the literature

Fig. 2. Simulation diagram of X-ray irradiation on human head model

Fig. 3. Comparison of four methods for calculating brain absorbed dose

Fig. 4. Mean free path of photon at energy E

Fig. 5. 30 keV, 60 keV and 120 keV photon tracks in the head phantom

Fig. 6. Curve of relative error of absorbed dose for track length energy deposition method and pulse height method in water sphere

Fig. 7. Absorbed dose at different gadolinium content in tumor