radioactive substances(radionuclides )
are material that emit high-speed particles and energy -containing rays from the interior of their matter.
nuclear medicine
is the medical specialty that uses radioactive substances in the diagnosis and treatment of disease
Radioactivity
is the emitted particles and rays, and can be three types.Alpha particles, Beta particles , and Gamma rays.
Gamma rays
are used effectively as a diagnostic label to trace the path and uptake of chemical substances in the body