Question: How do you make medicines out of radioactive substances?

Thomas Biggans answered on 15 Jun 2016:

Sometimes we can just use the radioactive substance to treat disease for example radioactive iodine is naturally absorbed by the thyroid so we use it to treat thyroid cancer or radioactive radium is naturally absorbed by bone so we can use it to treat cancer that has spread to the bones. The radiation given off by the sources kills the cancer cells.

For other areas of interest we have to attach the radioactive isotope to a pharmaceutical that is processed in the area of interest. For example we can attach radioactive technetium to a drug called tetrofosmin. Tetrofosmin travels with the blood and is then absorbed by healthy myocardial tissue (heart muscle) and because our technetium is attached to the tetrofosmin it too is absorbed into the heart muscle. Now we can get a picture of where the technetium is in the heart by detecting the radiation it is emitting. This shows us if all of the heart muscle is still healthy and if not what areas of the heart muscle are not working.

By using other pharmaceuticals we can examine the function of other organs using the same radioactive substance. So the body processes the drug and we detect the radiation coming from isotope we’ve attached to the drug.