  In this paper we study the sensitivities of electron dose calculations with
respect to the stopping power and the transport coefficients. We focus on the
application to radiotherapy simulations. We use a Fokker-Planck approximation
to the Boltzmann transport equation. Equations for the sensitivities are
derived by the adjoint method. The Fokker-Planck equation and its adjoint are
solved numerically in slab geometry using the spherical harmonics expansion
($P_N$) and an HLL finite volume method. Our method is verified by comparison
to finite difference approximations of the sensitivities. Finally, we present
numerical results of the sensitivities for the normalized average dose
deposition depth with respect to the stopping power and transport coefficients,
demonstrating the increasing relative sensitivities as beam energy decreases.
