1 mG is a large field, compared to the MEG, MKG and magnetic radiation
of the internal organs( 10 -9 to 10 -6 Guass is typical). The earth's
field is about 0.5 Gauss, i.e.
the measured radiation is only 500 times weaker than the earth's
field, and therefore can be detected without a SQUID!!

Which "higher radiation levels" are you referring to? If the human
body emitted more than milligauss, it would affect compasses,
electrical equipment, and could be easily measured by coils! This is
not usually the case...