The medical sub domain that makes use of nuclear materials in order to treat or diagnose a number of diseases is called nuclear medicine. The diseases treated and diagnosed with the use of such materials include different types of cancer, heart disease as well as other bodily abnormalities. Around one third of the patients admitted to hospitals are either diagnosed or treated using nuclear materials.
The diagnostic procedure in nuclear medicine involves the use of radioisotopes or radiotracers which are either injected into a vein, swallowed or inhaled as gas by the patient. If more neutrons are added to a chemical element and if this combination does not exist in nature, the atom becomes unstable and is called a radioactive isotope.
These nuclear materials (radiotracers) are designed to be attracted by certain types of tissue (such as bone or tumour). The radiotracer is therefore collected in a certain area of the body which the doctors wish to treat or analyze. The radiotracer consists of radioisotopes. As already mentioned, radioisotopes are obtained by changing the number of neutrons within certain chemical elements. If these isotopes do not exist in nature, the atoms become unstable. For this reason, radioisotopes emit positrons (due to their instability) in the form of electromagnetic radiation or gamma rays. The photons emitted are then collected by a gamma camera. This way, images are produced which reflect a certain state of an area of the body (such as a bone, the heart or the brain) where the radiotracers are located. This in turn gives information about certain features of the area to be analyzed and is used for example for detecting tumours. The nuclear materials used in this domain of medicine reflect the main difference between a regular X-ray and diagnostic nuclear medicine imaging. The other main difference is that they can also be used for soft tissue.
Nuclear materials are also used in medicine for therapeutic purposes. Like in the diagnostic procedure, radioactive materials are used to irradiate certain organs or cells and they are attracted by certain types of cells or tissue. The radioactive elements are attached to a biological compound leading only to the area to be treated. When they reach their location in the body, the radioisotopes emit radiation into their target cells and organs and destroy or weaken the diseased cells. The radiation can be used for cancer therapy, pain relief, or to reduce the function of certain organs.
The use of radioactive materials in medicine presents a small risk of the patients developing cancer. Any therapeutic or diagnosis procedure involving the use of such materials is regulated by governmental agencies which issue and regulate medical licenses for this practice. In practice, the amount of radiation is kept as low as possible, but varies according to the progression of the disease to be treated. The waste resulting from the use of radioisotopes in medicine (such as towels, clothing or tools) undergo decay storage for up to a few years. After this, they are considered to be radioactive waste.
Article by Matt Smith on behalf of LTi Metaltech - specialist metal fabricators and welders of pressure vessels and nuclear waste containers.
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