2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/188904Vacuum polarization in QED in a background gravitational field induces interactions which {\it effectively} modify the classical picture of light rays as the null geodesics of spacetime. After a short introduction on the main aspects of the quantum gravitational optics, as a nontrivial example, we study this effect in the background of NUT space characterizing the spacetime of a spherical mass endowed with a gravitomagnetic monopole charge, the so called NUT factor.9 pages, title changed and the text abridged for publication in the Journal of Physics: Conference seriesGeneral Relativity and Quantum Cosmologytext