A wide variety of radioactive materials (compounds and forms) are used at UMSL. Of course, each has the same physical and chemical properties of the corresponding non-radioactive material. Most radiolabeled materials in biomedical research are compounds in which a stable atom of Hydrogen, Carbon, Phosphorous, or Sulfur has been replaced by a radioactive atom of the same element. Radiolabeled compounds can be natural or synthetic, organic or inorganic. Nucleotide tri-phosphates, amino acids, salts in aqueous solution, fatty acids, proteins, sugars, ligands, even water are just a few radiolabeled compound groups that are commonly used in biomedical research. Radioactive materials consist of sealed and unsealed sources.
Most radioactive materials in biomedical research are purchased as liquid solutions of radiolabeled materials. When we use radioactive materials in unsealed form, we are interested in detecting emitted radiation to find out what is happening chemically and/OR physically to the radiolabeled material (nucleic acid, enzymes, proteins, cells etc.).
"Sealed" sources contain the radioactive material bound either by encapsulation, incorporated into metal matrix, or even electroplated on a check source, etc. These sealed sources are used in situ to produce a specific type of radiation (typically gamma). Sealed sources are by definition fixed non-removable material since the radioactive material is encapsulated or part of a metal matrix.
The gamma emitting sealed sources will produce an external exposure rate field that is easily measurable. The material itself remains fixed within the capsule and is returned behind shielding after use. Blood bank irradiators are common examples of sealed sources.
