The discussion centers around the Bragg-Gray theory and its application in calculating dose in water for 45 MV using both the Bragg-Gray cavity method and the equation for electronic equilibrium. The initial query raised concerns about obtaining similar results from both methods, despite expectations of significant differences. Clarifications were made regarding the Bragg-Gray theory, which relies on the assumption of charged particle equilibrium in a small cavity within a medium, where ionization is proportional to absorbed dose and does not alter the radiation's spectral characteristics. The conclusion reached indicates that charged particle equilibrium is less restrictive at lower energies compared to higher energies, which explains the similar results obtained in the calculations.
