ABSTRACT
Nuclear medicine consists of a range of diagnostic and therapeutic procedures that use radioisotopes. This chapter focuses on the diagnostic uses of radioisotopes. Radioactive iodine is chemically identical to normal iodine and so if some radioactive iodine is given orally a fraction of it will appear in the thyroid gland after a period of time. Isotopes are atoms of the same element which have different numbers of neutrons. They are referred to by their atomic mass number. The neutrons and protons are often referred to generically as nucleons. Within the bulk of the periodic table there is one element, technetium, which also has no stable isotopes. Coincidentally a radioisotope of this element is widely used in nuclear medicine. The energy of any nuclear radiation can be related to the mass which was lost when the atom decayed and emitted the radiation.
