
134 Statistical Computing in Nuclear Imaging
ticles that do not have any electric change. They likely have a mass but
t
he upper bound on the value of this mass is so tiny that it has not bee n
experimentally validated yet. The antineutrino and neutrino interact with
other matter only through weak
1
and gravitational forces and are extremely
difficult to detect a nd study experimentally. Because of this reason we will
not be concerned with neutrinos in imaging.
When one of neutr ons in the nucleus is converted to a proton, the atomic
number of the nucleus is increased by one (as is the positive charge) and
the mass number remains the same. It is represe nted ...