OBJECTIVE: Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. MATERIALS AND METHODS: Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. RESULTS: Intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h^–1.p ^–1.s, respectively, on the healthy tissue, on the balloon periphery and on the I₁ and I₂ tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h^–1.p ^–1.s, respectively on the healthy tissue, on the target tumor and on the I₁ and I₂ infiltration zones. CONCLUSION: Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones.

Keywords: Brachytherapy; Glioblastoma multiforme; Dosimetry; BNCT; MCNP.