A medical isotope is a safe radioactive substance used primarily to diagnose illness. The energy emitted by the isotope when inside a patient is detected by special cameras while the patient is being scanned. The branch of medicine and medical imaging that uses these isotopes is known as nuclear medicine.
Where are radioisotopes used?
In medicine, for example, cobalt-60 is extensively employed as a radiation source to arrest the development of cancer. Other radioactive isotopes are used as tracers for diagnostic purposes as well as in research on metabolic processes.
Difference between Alpha, Beta and Gamma radioactive decay can be summarized as follows: Alpha decay forms new element with two fewer protons and two fewer neutrons; Gamma decay forms NO new element, but now the element has less energy because energy is released as gamma rays.
Nuclear medicine is a branch of medical imaging that uses small amounts of radioactive material to diagnose and determine the severity of or treat a variety of diseases, including many types of cancers, heart disease, gastrointestinal, endocrine, neurological disorders and other abnormalities within the body.
Nuclear medicine procedures are used in diagnosing and treating certain illnesses. These procedures use radioactive materials called radiopharmaceuticals. Examples of diseases treated with nuclear medicine procedures are hyperthyroidism, thyroid cancer, lymphomas, and bone pain from some types of cancer.
Radiation Therapy to Treat Cancer. Radiation therapy (also called radiotherapy) is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. At low doses, radiation is used in x-rays to see inside your body, as with x-rays of your teeth or broken bones.
The median annual wage for nuclear medicine technologists is $74,350. The median wage is the wage at which half the workers in an occupation earned more than that amount and half earned less. The lowest 10 percent earned less than $53,440, and the highest 10 percent earned more than $101,850.
Nuclear medicine technicians or nuclear medicine technologists (NMTs) use radioactive materials to diagnose and treat diseases under the supervision of a physician. They prepare radiopharmaceuticals, administer them to patients, and use imaging devices to record the distribution within a patient's body.
Gamma radiation is the product of radioactive atoms. Man-made sources are produced by introducing an extra neutron to atoms of the source material. For example, Cobalt-60 is produced by bombarding a sample of Cobalt-59 with an excess of neutrons in a nuclear reactor.
These are considered nuclear medicine because the patient receives an injection that is radioactive, called a radio-pharmaceutical as part of the imaging. (An MRI or CT Scan can sometimes require an injection, but it is not a radiopharmaceutical, so they are not nuclear medicine.)
Radioactive isotopes have many useful applications. In medicine, for example, cobalt-60 is extensively employed as a radiation source to arrest the development of cancer. Other radioactive isotopes are used as tracers for diagnostic purposes as well as in research on metabolic processes.
Many radiopharmaceuticals use technetium-99m (Tc-99m) which has many useful properties as a gamma-emitting tracer nuclide. The term radioisotope, which in its general sense refers to any radioactive isotope (radionuclide), has historically been used to refer to all radiopharmaceuticals, and this usage remains common.
A radioisotope used for diagnosis must emit gamma rays of sufficient energy to escape from the body and it must have a half-life short enough for it to decay away soon after imaging is completed. The radioisotope most widely used in medicine is Tc-99, employed in some 80% of all nuclear medicine procedures.
Technetium-99m is produced by bombarding Molybdenum (98Mo) with neutrons. Technetium generators, which contain the radioisotope, are supplied to hospitals from the nuclear reactor where the isotopes are made. They contain Molybdenum-99, with a half-life of 66 hours, which progressively decays to technetium-99.
Alpha (α) decay. When an alpha particle is emitted from a nucleus the nucleus loses two protons and two neutrons. This means the atomic mass number decreases by 4 and the atomic number decreases by 2. A new element is formed that is two places lower in the Periodic Table than the original element.
Cobalt-60 is a beta-emitting radioactive isotope of cobalt-59. In cobalt-60 therapy, cobalt-60-generated gamma radiation is used to destroy tumors. Cobalt-60 therapy is also known as Gamma Knife® therapy. Gamma Knife® is a registered trademark of Elekta Instruments, Inc.
Diagnostic techniques in nuclear medicine use radioactive tracers which emit gamma rays from within the body. These tracers are generally short- lived isotopes linked to chemical compounds which permit specific physiological processes to be scrutinised. They can be given by injection, inhalation or orally.
Because of this specificity, a radioactive isotope of iodine can be used to image the thyroid. There are many radioactive isotopes of iodine, for imaging Iodine-123 (I-123) is most often used. I-123 is a positron ( β+ ) emitter, therefore positron imaging techniques are used such as PET and SPECT.
Iodine-131 is used to treat certain types of thyroid cancer and some rarer types of cancer. You may need to stay in hospital for this treatment. Strontium-89 and samarium-153 is used to treat some types of secondary bone cancer. They can help reduce pain.
Nuclear medicine can be used for image physiological functions. Common isotopes that are used in nuclear imaging include: fluorine-18, gallium-67, krypton-81m, rubidium-82, nitrogen-13, technetium-99m, indium-111, iodine-123, xenon-133, and thallium-201.
According to the World Nuclear Association, these were the top 10 nuclear-dependent nations in 2011:
- France – 77.7 percent of electricity from nuclear.
- Belgium – 54.0 percent.
- Slovakia – 54.0 percent.
- Ukraine – 47.2 percent.
- Hungary – 43.2 percent.
- Slovenia – 41.7 percent.
- Switzerland – 40.8 percent.
- Sweden – 39.6 percent.