## 3 Results
### Percentual Depth Dose and Dose Profiles  
The subsequent figures present the examination of PDD and Dose Profiles for four distinct materials: Water, Co-Cr-Mo Alloy, Ti Alloy, and Stainless Steel. Our objective is to evaluate the impact of metallic materials on dose distribution, particularly in the regions adjacent to and behind the box, where attenuation and dispersion occur. In the PDD, we concentrated on depth values of 1, 2, 3, 5, 10, and 15 cm, while for the dose profiles, we recorded the dose values at the origin of the \(x\)-axis. Our reference was the dose distribution values for water absent from the metal box. In Figure 4a, the metal box is situated at a depth of 5 cm, with an energy of 6 MV for photons. The dose distributions with the metal box exhibit significant dose attenuation attributable to the metal box itself. The Co-Cr-Mo alloy exhibits the most significant dose reduction, with a decrease of 15.16% at \(d_{15}\). A notable reduction in dose is evident in the center plane of plot b for all metallic materials: Co-Cr-Mo alloy at 67.87%, stainless steel at 77.47%, and titanium at 88.43%. Dose values are normalized to the maximum dose in water (100%). Values exceeding 100% represent localized build-up effects and should be interpreted as relative, not absolute, increases. Figure 3: Two-dimensional dose distribution of different energies. Simulations of the dose distributions for 15 MeV (Figure 5) for electrons show significant differences in the dose distributions, depending on the presence of the metal box and the materials used. In water, the dose rate reaches 88.63% at a depth of 1 cm, with a gradual decrease in dose consistent with the expectation for the electron beam. The metallic materials cause a significant attenuation, with the Co-Cr-Mo alloy showing the largest decrease in dose, with values of 82.88% at 1 cm depth and 38.75% at 5 cm depth. Titanium and stainless steel show similar behavior, with a more moderate attenuation compared to Co-Cr-Mo, with dose rates of 82.7% and 80.92% at 1 cm depth and values of around 39.00% at 5 cm depth. The crossline profile in water reaches 99.30%, while it drops to 4.00% for Co-Cr-Mo, demonstrating a significant lateral attenuation. Titanium has a crossline dose of 18.59%, and steel reaches 74.40%. The inline profile in water shows a maximum dose of 100% but drops to 4.04% for the Co-Cr-Mo alloy, with titanium and steel reaching 18.67% and 74.86%, respectively. The tabular data supports these observations, where Co-Cr-Mo causes the most significant attenuation at depths of 1 cm to 5 cm, while titanium and steel show moderate attenuation. Figure 4: (**a**) PDDs for 6 MV (photons) with metal box; (**b**) dose profiles for 6 MV (photons) with metal box. Figure 5: (**a**) PDDs for 15 MeV (electrons) with metal box; (**b**) dose profiles for 15 MeV (electrons) with metal box. Simulations of the dose distributions for 100 MeV VHEE (Figure 6) reveal distinct differences in dose behavior contingent upon the material and the presence of the metal box. At a depth of 1 cm in water, the dose attains 88.00%, which is analogous to the measurements for titanium alloy (88.16%), stainless steel (88.10%), and Co-Cr-Mo alloy (88.00%). The disparities in batch behavior are increasingly evident at increased depths. At a depth of 5 cm, the dose in water attains 95.45%, whereas the Co-Cr-Mo alloy exhibits 85.76%, indicating the most significant attenuation. Titanium and steel exhibit moderate attenuation, with doses of 86.00%. At a depth of 15 cm, the dose in water is 97.79%, whereas for the Co-Cr-Mo alloy, it decreases to 63.22%, demonstrating its substantial impact on dose attenuation. The crossline profiles indicate a substantial reduction in dose for metallic materials, with water achieving 100% and Co-Cr-Mo diminishing to 43.32%. Titanium attains 77.01%, whereas stainless steel achieves 52.18%. The inline profiles exhibit analogous behavior, with Co-Cr-Mo decreasing to 43.71% compared to 98.61% in water.