Diagnosis, therapy, research. The medical profession relies heavily on direct radiation fields and radioactive isotopes for identifying and treating disease. In addition, radioactive materials are used extensively to test new drugs and conduct research into cures for disease.
Our high standard of health and quality of life would not be possible without the use of radioactive materials. Today, radioactive materials are used throughout the world for medical purposes. In the United States alone, one in three of the 30 million Americans who are hospitalized are diagnosed or treated with nuclear medicine techniques. Radionuclides are used in more than 11 million nuclear medicine procedures every year in the United States. They also are used in 100 million laboratory tests on body fluid and tissue specimens.
Radioactive materials used in medicine: radionuclides and radioactive isotopes. A radionuclide is any type of radioactive material, including elements and the isotopes of elements. An isotope of an element is a particular atomic "version" of it. Isotopes are atoms of the same element with different atomic structures. They have the same number of protons--making them the same element--but different numbers of neutrons--making them isotopes. There are 81 stable isotopes and over 800 unstable, that is, radioactive, isotopes. Most radioactive materials used in nuclear medicine are isotopes, because a particular medical use will require a given isotope's specific radioactive properties. One radioactive isotope developed at Brookhaven National Laboratory in New York, molybdenum-99, is used about 40,000 times each day in the United States to diagnose cancer and other illnesses.
|Diagnostic Uses of Radioactive Materials|
Tracers: bone scans, kidney scans, and others. Radioactive isotopes and radioactively labeled molecules are used as tracers to identify abnormal bodily processes. This is possible because some natural elements tend to concentrate in certain parts of the body: iodine in the thyroid, phosphorus in the bones, potassium in the muscles. When a patient is injected with a radioactive element, a special camera can take pictures of the internal workings of the organ.
Examples of radioactive tracer medical procedures.
- Myocardial perfusion imaging maps the blood flow to the heart, allowing physicians to see whether a patient has heart disease and determine what kind of treatment will be most effective.
- Bone scans can detect the spread of cancer six to 18 months sooner than X-rays.
- Kidney scans are much more sensitive than X-rays or ultrasound in fully evaluating kidney function.
- Imaging with radioactive technetium-99m can help diagnose bone infections in young children at the earliest possible stage.
- Laboratory techniques using radioactivity can detect underactive thyroids in newborn babies, making prompt treatment possible and saving many children from mental retardation.
Uses of Radioactive Materials in Medical Research and Testing.
- Biomedical research. Radioactive materials also are essential to the biomedical research that seeks causes and cures for diseases like AIDS, cancer and Alzheimer's disease.
- Pharmaceutical drug testing. The U.S. Food and Drug Administration requires all new pharmaceutical drugs to be tested for safety and effectiveness. More than 80 percent of those drugs are tested with radioactive materials. One of the main tests is to determine if the pharmaceutical is going to other parts of the body than the intended target and what effect it has on the non-target areas. By adding a radioactive tag to the pharmaceutical, researchers can pinpoint all parts of the body and the concentration that accumulates in non-target areas. From this they can determine if there is likelihood of adverse reactions in other parts of the body.
- Metabolic research. Radionuclides are used extensively in metabolic studies and genetic engineering.
- Chemical reaction imaging. The latest single photon emission typography (SPET) or positron emission tomography (PET) enable scientists to watch color images of chemical reactions in living tissue and, in particular, to trace opioid molecules--naturally occurring morphine-type drugs--which eliminate pain within the brain.
|Manufacturing Radioactive Materials|
Natural versus manufactured radioactive materials. Some radioactive elements, such as radium, are found in nature, but most radioactive materials are produced commercially in nuclear reactors or cyclotrons--also called particle accelerators. With nuclear reactors and cyclotrons, it is possible to make useful amounts of radioactive material safely and at low cost.
How radioactive materials are manufactured. A cyclotron uses electric current to accelerate atomic particles, which strike the non-radioactive "target" material, turning it into a radioactive isotope--variant--of its original structure. For example, when the non-radioactive "target" element cobalt is struck by neutrons in a reactor, it is transformed into a radioisotope--cobalt-60--which is used to treat cancer and sterilize medical and consumer products.
The difference between cyclotron and reactor manufacturing. Usually only one type of radionuclide can be produced at a time in a cyclotron, while a reactor can produce many different radionuclides simultaneously.
Radioactive materials safely packaged and shipped to users. Once radionuclides are produced, they are packaged and safely shipped to users throughout the country, including hospitals, laboratories, universities and manufacturing plants.
Regulating the manufacturing of radioactive materials. Companies that produce and sell radioactive materials are licensed and inspected by the U.S. Nuclear Regulatory Commission or the state regulatory agency, and--if the product is a pharmaceutical--by other agencies, including the Food and Drug Administration.