Radiosensitization effects of BaTiO₃ and gold nanoparticles in proton therapy of pancreatic tumors: A Monte Carlo study.

OBJECTIVES: This study investigates the potential of barium titanate (BaTiO3) nanoparticles to enhance the therapeutic efficacy of proton therapy for pancreatic tumors in comparison to gold nanoparticles through both macroscopic and microscopic simulations. MATERIALS AND METHODS: Using the MCNP6.1 Monte Carlo code, we modeled a 3cm pancreatic tumor in the head of the pancreas loaded with clusters of BaTiO3 and gold nanoparticles using a lattice model. Proton beam (SOBP, 135 MeV) interactions were simulated to evaluate the dose enhancement factor (DEF) within the tumor, the non-tumor pancreas, and Organs At Risks (OARs). Additionally, microscopic dosimetry was conducted to study the dose deposition in the vicinity of the clusters containing nanoparticles. RESULTS: The gold nanoparticles present DEF of 1.21 and BaTiO3 nanoparticles present DEF of 1.14 in the tumor site. The OARs remained mainly unaffected. Also, on a microscopic scale, DEF values of 1.7-1.83 in the presence of gold nanoparticles and 1.42-1.51 in the presence of BaTiO3 nanoparticles were calculated. The microscopic DEFs were more than the macroscopic DEF. CONCLUSION: Both gold and BaTiO₃ nanoparticles enhanced proton dose deposition, with gold nanoparticles producing greater macroscopic and microscopic DEFs. The results also show that microscopic dose enhancement exceeds macroscopic dose enhancement, confirming that most proton-induced dose enhancement occurs in the close vicinity of nanoparticles. Because this study is based on Monte Carlo simulations with a uniform nanoparticle distribution and without biological modeling, further experimental studies are needed to validate these findings.