Many years ago, it was discovered that radiation could be
used to kill cancer cells and, in some cases, even cure the disease.
Early work concentrated on the use of external beams of radiation,
but it became apparent that radiation delivered internally, and
aimed precisely, would be more effective. The challenge then
became how to direct the  right
amount of radioactivity to the target cancer cells while avoiding
damage to healthy cells.
In the case of thyroid cancer, it was surprisingly easy. We have
known for more than a century that a certain amount of iodine in
the diet is necessary for a healthy thyroid. [Adding iodine to table
salt at the processing plant became a simple and inexpensive way
to prevent deficiency—not everyone can afford a trip to the oceanside
to breathe in the sea air.] Iodine in its natural state is an element
with an atomic mass of nearly 127. By splitting a heavy atom, we
can make iodine that has four more neutrons than usual in a controlled
process in a nuclear reactor. This is a new
isotope,
the radionuclide called Iodine-131. Because of the extra
neutrons, Iodine-131 is "unstable," and it seeks to get
rid of them. Shedding those extra neutrons releases energy—radiation
—that kills the cancer. Iodine-131 is so good at hunting down
thyroid cancer that the death rate for patients having this disease
is very low. Indeed, Iodine-131 often finds and cures thyroid cancer
cells that have spread to other parts of the body. Cancer that spreads
from one site to other areas is called "metastatic" cancer.
Unfortunately, there are no other radionuclides that act independently
to hunt down other forms of cancer. They need some kind of guidance
system to get them to the cancer, wherever it may be in the body.
Radiopharmaceuticals are radioactive
drugs that contain a radioisotope bound to a molecule capable
of homing to specific tissues in a patient. This results in selective
delivery of the radioisotope (or radionuclide) to predetermined
tissues and organs in the body. Researchers at the University
of Missouri-Columbia (MU) departments of Chemistry and Biochemistry
are developing special, natural biomolecules to be the carriers
to the tumors. However, even a good guiding molecule is useless
without pure, highly concentrated radionuclides to attach to
them.
Enter the University of Missouri Research Reactor Center (MURR)
and its research staff...
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University of Missouri-Columbia
