  In this paper we study reconstruction of a function $f$ from its discrete
Radon transform data in $\mathbb R^3$ when $f$ has jump discontinuities.
Consider a conventional parametrization of the Radon data in terms of the
affine and angular variables. The step-size along the affine variable is
$\epsilon$, and the density of measured directions on the unit sphere is
$O(\epsilon^2)$. Let $f_\epsilon$ denote the result of reconstruction from the
discrete data. Pick any generic point $x_0$ (i.e., satisfying some mild
conditions), where $f$ has a jump. Our first result is an explicit leading term
behavior of $f_{\epsilon}$ in an $O(\epsilon)$-neighborhood of $x_0$ as
$\epsilon\to0$.
  A closely related question is why can we accurately reconstruct functions
with discontinuities at all? This is a fundamental question, which has not been
studied in the literature in dimensions three and higher. We prove that the
discrete inversion formula `works', i.e. if $x_0\not\in S:=\text{singsupp}(f)$
is generic, then $f_{\epsilon}(x_0)\to f(x_0)$ as $\epsilon\to0$. The proof of
this result reveals a surprising connection with the theory of uniform
distribution (u.d.). This is a new phenomenon that has not been known
previously. We also present some numerical experiments, which confirm the
validity of the developed theory.
