This study aims to establish phantom-solution systems suitable for estimating doses in boron neutron capture therapy (BNCT). The phantom containing three typical solutions, H 3 BO 3 , LiOH, and Gd(NO₃)₃·6H₂O with different concentrations and nuclide abundances have been studied since the nuclides 10 B, 6 Li, and 157 Gd are capable of absorbing thermal neutrons. The results indicate that all three phantom-solution systems, with suitable concentrations and nuclide abundances, effectively distinguish between the nitrogen dose and the hydrogen dose for dose measurement in BNCT.