synthetic radioisotope

Information about synthetic radioisotope

A synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. Examples include technetium-95 and promethium-146. Many of these are found in, and harvested from, spent nuclear fuel assemblies. Some must be manufactured in particle accelerators.

Production

Some synthetic radioisotope are extracted from spent nuclear reactor fuel rods, which contain various fission products. For example, it is estimated that up to 1994, about 49,000 TBq (78 metric ton) of technetium was produced in nuclear reactors, which is by far the dominant source of terrestrial technetium. However, only a fraction of the production is used commercially. Other synthetic isotopes are produced in significant quantities by fission but are not yet being reclaimed. Other isotopes are manufactured by neutron irradiation of parent isotopes in a nuclear reactor (for example, Tc-97 can be made by neutron irradiation of Ru-96) or by bombarding parent isotopes with high energy particles from a particle accelerator.^[1]

Uses

Most synthetic radioisotopes are extremely radioactive and have a short half life. Though a health hazard, radioactive materials have many medical and industrial uses.

Nuclear medicine

The general field of nuclear medicine covers any use of radioisotopes for diagnosis or treatment.

Diagnosis

Radioactive tracer compounds are used to observe the function of various organs and body systems. These compounds use a chemical tracer which is attracted to or concentrated by the activity which is being studied. That chemical tracer incorporates a short lived radioactive isotope, usually one which emits a gamma ray which is energetic enough to travel through the body and be captured outside by a gamma camera to map the concentrations. Gamma cameras and other similar detectors are highly efficient, and the tracer compounds are generally very effective at concentrating at the areas of interest, so the total amounts of radioactive material needed are very small.

The metastable nuclear isomer Tc-99m is a Gamma-emitter widely used for medical diagnostics because it has a short half-life of 6 hours, but can be easily made in the hospital using a "technetium-cow".

Treatment

Radiopharmaceuticals are any of a number of compounds using a radioisotope for medical treatment, usually by bringing the radioactive isotope to a high concentration in the body near a particular organ. For example, iodine-131 is used for treating some disorders and tumors of the thyroid gland.

Industrial radiation sources

Alpha particle, beta particle, and gamma ray radioactive emissions are industrially useful. Most sources of these are synthetic radioisotopes.

Footnotes

1. ^ Brookhaven National Laboratory, Medical Department, "Radioisotope Production."

External links

Map of the Nuclides at LANL T-2 Website

A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created radiation particle within the nucleus, or else to an atomic electron (see internal conversion) .
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Technetium (IPA: /tɛkˈniʃɪəm/ or /tɛkˈniːʃɪəm/) is the lightest chemical element with no stable isotope. It has atomic number 43 and is given the symbol Tc.
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Promethium (IPA: /prə(ʊ)ˈmiːθiəm/) is a chemical element in the periodic table that has the symbol Pm and atomic number 61.
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particle accelerator is a device that uses electric fields to propel electrically charged particles to high speeds and to contain them. An ordinary CRT television set is a simple form of accelerator. There are two basic types: linear (i.e.
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UO₂ pellets in zircaloy cladding.]]

The key components common to most types of nuclear power plants

Neutron moderator
Coolant
Control rods
Pressure vessel
Emergency Core Cooling Systems (ECCS)
Reactor Protective System (RPS)

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The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second. It is therefore equivalent to s^-1.
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tonne (t) or metric ton (M/T), also referred to as a metric tonne, is a measurement of mass equal to 1,000 kilograms. It is not an SI unit but is accepted for use with the SI.
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Neutron

The quark structure of the neutron.
Composition: one up, two down
Family: Fermion
Group: Quark
Interaction: Gravity, Electromagnetic, Weak, Strong
Antiparticle: Antineutron
Discovered: James Chadwick^[1]
Symbol: n
Mass: 1.
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For , see .

The half-life of a quantity, subject to exponential decay, is the time required for the quantity to decay to half of its initial value.
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Nuclear medicine is a branch of medicine and medical imaging that uses the nuclear properties of matter in diagnosis and therapy. Many procedures in nuclear medicine use pharmaceuticals that have been labeled with radionuclides (radiopharmaceuticals).
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For the music band, see .

Gamma rays or gamma-ray (denoted as γ) are forms of electromagnetic radiation (EMR) or light emissions of a specific frequency produced from sub-atomic particle interaction, such as electron-positron annihilation and
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A gamma camera is a device used in nuclear medical imaging also known as nuclear medicine, to view and analyse images of the human body of the distribution of medically injected, inhaled, or ingested gamma ray emitting radionuclides.
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A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its nucleons. A nuclear isomer occupies a higher energy state than the corresponding non-excited nucleus, called the ground state.
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A technetium-99m generator, or colloquially a technetium cow is a device used to extract the metastable isotope ^99mTc of technetium from a source of decaying molybdenum-99.
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Radiopharmacology is the study and preparation of radiopharmaceuticals, which are radioactive pharmaceuticals. Radiopharmaceuticals are used in the field of nuclear medicine as tracers in the diagnosis and treatment of many diseases.
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Iodine (IPA: /ˈaɪədaɪn, ˈaɪədɪn/, or /ˈaɪədiːn/; from Greek: iodes
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Alpha particles (named after and denoted by the first letter in the Greek alphabet, α) consist of two protons and two neutrons bound together into a particle identical to a helium nucleus; hence, it can be written as He²⁺ or ⁴₂He.
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Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei such as potassium-40. The beta particles emitted are a form of ionizing radiation also known as beta rays. The production of beta particles is termed beta decay.
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