In some cases the EM radiation emitted from scanners could aggravate conditions or accelerate a disease, as shown when Doctor Bashir encountered a Dominion virus which was engineered to be excited by EM radiation emitted from Starfleet equipment, subsequently killing all his patients. (DS9: "The Quickening") In 2371, Tom Paris told Tuvok to run a lateral EM scan at coordinates 18 mark 40 to proove his assumption, Voyager was "not alone" in orbit of a class M planet. (VOY: "State of Flux")