  We prove a logarithmic stability estimate for the time dependent X-ray
transform on $\mathbb{R}_t^+\times\mathbb{R}^n$. To do so, we extend a known
result by Begmatov for the stability of the time dependent X-ray transform in
$\mathbb{R}^+_t\times\mathbb{R}^2$. We give some examples of stability and
injectivity results in relationship to the Dirichlet-to-Neumann problem. In
particular, under the Geometric Control Condtion, we derive inverse logarithmic
stability estimates for time dependent conformal factors.
