  We discuss in detail the calculation of the leading order QCD corrections to
the Effective Hamiltonian which governs $b \rightarrow s\, \gamma$ and $b
\rightarrow s \, g$ transitions in three different regularization schemes (HV,
NDR and DRED). We show that intermediate stages of the calculation do depend on
the regularization, but the same scheme independent coefficients can be
obtained in all the considered schemes. A detailed discussion of the results
already present in the literature is also given.
