What makes radioactive isotopes

This method also presented formidable technical challenges, but was eventually implemented in the gigantic gas diffusion plant at Oak Ridge, Tennessee. In this process, the uranium was chemically combined with fluorine to form a hexafluoride gas prior to separation by diffusion. This is not a practical method for extracting radioisotopes for scientific and medical use.

It was extremely expensive and could only supply naturally occurring isotopes. A more efficient approach is to artificially manufacture radioisotopes.

This can be done by firing high-speed particles into the nucleus of an atom. When struck, the nucleus may absorb the particle or become unstable and emit a particle. In either case, the number of particles in the nucleus would be altered, creating an isotope.

One source of high-speed particles could be a cyclotron. A cyclotron accelerates particles around a circular race track with periodic pushes of an electric field. The particles gather speed with each push, just as a child swings higher with each push on a swing. When traveling fast enough, the particles are directed off the race track and into the target.

A cyclotron works only with charged particles, however. Another source of bullets are the neutrons already shooting about inside a nuclear reactor. The neutrons normally strike the nuclei of the fuel, making them unstable and causing the nuclei to split fission into two large fragments and two to three "free" neutrons. These free neutrons in turn make additional nuclei unstable, causing further fission. The result is a chain reaction.

Too many neutrons can lead to an uncontrolled chain reaction, releasing too much heat and perhaps causing a "meltdown. In this way the surplus neutrons are used to create radioactive isotopes of the materials placed in the targets.

In December Congress passed the American Medical Isotope Production Act of to establish a technology-neutral program to support the production of Mo for medical uses in the USA by non-federal entities.

In February , the Department of Energy's National Nuclear Security Administration NNSA selected four companies to begin negotiations for potential new cooperative agreement awards for the supply of molybdenum, mostly from accelerators. Niowave is developing superconducting electron linear accelerators, NorthStar Medical Radioisotopes is planning to irradiate Mo targets to produce Mo in a reactor, while in the longer term it is developing a method using a linear accelerator.

See below for fuller descriptions. Such Mo has relatively low specific activity, and there are complications then in separating the Tc The company received approval to begin routine production in August , and aims eventually to meet half of US demand with six-day TBq per week. MURR runs on low-enriched uranium.

Longer-term NorthStar is considering a non-reactor approach. In , NorthStar Medical Radioisotopes signed an agreement with Westinghouse to investigate production of Mo in nuclear power reactors using its Incore Instrumentation System.

It is aiming to set up a 44, m 2 radioisotope production facility in Columbia, Missouri. The NRC approved the plans in May However, Nordion withdrew from the project in April citing delays and cost overruns that had increased the project's commercial risk. An earlier proposal for Mo production involving an innovative reactor and separation technology has lapsed.

They planned to use Aqueous Homogeneous Reactor AHR technology with LEU in small kW units where the fuel is mixed with the moderator and the U forms both the fuel and the irradiation target. As fission proceeds the solution is circulated through an extraction facility to remove the fission products with Mo and then back into the reactor vessel, which is at low temperature and pressure.

In mid Los Alamos National Laboratory announced that it had recovered Mo from low-enriched sulphate reactor fuel in solution, raising the prospect of this process becoming associated with commercial reprocessing plants as at La Hague in France.

JSC Isotope was founded in and incorporated in Brazil is a major export market. Its product portfolio includes more than 60 radioisotopes produced in cyclotrons, nuclear reactors by irradiation of targets, or recovered from spent nuclear fuel, as well as hundreds of types of ionizing radiation sources and compounds tagged with radioactive isotopes.

It has more than 10, scientific and industrial customers for industrial isotopes in Russia. The Karpov Institute gets some supply from Leningrad nuclear power plant. Australia's Opal reactor has the capacity to produce half the world supply of Mo, and with the ANSTO Nuclear Medicine Project will be able to supply at least one-quarter of world demand from Tcm or Mo can also be produced in small quantities from cyclotrons and accelerators, in a cyclotron by bombarding a Mo target with a proton beam to produce Tcm directly, or in a linear accelerator to generate Mo by bombarding an Mo target with high-energy X-rays.

It is generally considered that non-reactor methods of producing large quantities of useful Tc are some years away. At present the cost is at least three times and up to ten times that of the reactor route, and Mo is available only from Russia.

If Tc is produced directly in a cyclotron, it needs to be used quickly, and the co-product isotopes are a problem. An LEU target solution is irradiated with low-energy neutrons in a subcritical assembly — not a nuclear reactor. The neutrons are generated through a beam-target fusion reaction caused by accelerating deuterium ions into tritium gas, using a particle accelerator. SHINE is an acronym for 'subcritical hybrid intense neutron emitter'. Construction at Janesville, Wisconsin commenced in August on 'Building One' and in May on the main production facility, which would eventually be capable of producing over one-third of global Mo demand.

A hour test run of Phoenix's high-flux neutron generator was in June Its Cassiopeia plant at Janesville is to produce , doses of Lu per year from At Lansing in Michigan, Niowave is using a superconducting electron linear accelerator to produce isotopes from fission of low-enriched uranium. It reports production of Mo, I, Sr and Xe among many others. Cobalt has mostly come from Candu power reactors by irradiation of Co in special rods for up to three years or five in RBMK , and production is being expanded.

Most of this Co is used for sterilization, with high-specific-activity Co for cancer treatment. Much of the Co is supplied through Nordion. The process will use Areva NP's patent-pending method of producing radioisotopes using a heavy water nuclear power plant. Orano Med built a small plant at Bessines-sur-Gartempe in France to provide Pb from irradiated thorium, and this came online in It was extended with a fivefold increase in capacity in A second plant has been built at Plano in Texas, operating from , and a new industrial-scale plant is planned for Caen in France.

Ra is a natural decay product of Th, and indirectly, of Th Some iodine is produced at Leningrad nuclear power plant from tellurium oxide, using irradiation channels in the RBMK reactors. A contract with the Karpov Institute of Physical Chemistry provides for delivery of 2. In Rosatom announced the establishment of a radiopharmaceutical production plant at the Institute of Reactor Materials IRM , which had started with lutetium, producing 24 TBq of it in Ci.

The IRM will also produce iodine and iridium, and its products will be distributed through Isotop. Urenco Stable Isotopes at Almelo uses centrifuge technology to produce by centrifuge enrichment a variety of stable isotopes for medical applications. A new cascade commissioned in is designed to produce multiple isotopes, including those of cadmium, germanium, iridium, molybdenum, selenium, tellurium, titanium, tungsten, xenon and zinc.

Many radioisotopes are made in nuclear reactors, some in cyclotrons. Generally neutron-rich ones and those resulting from nuclear fission need to be made in reactors; neutron-depleted ones such as PET radionuclides are made in cyclotrons with energy ranging from 9 to 19 MeV. There are about 40 activation product radioisotopes and five fission product ones made in reactors. Bismuth half-life: 46 min : Used for targeted alpha therapy TAT , especially cancers, as it has a high energy 8.

Chromium 28 d : Used to label red blood cells for monitoring, and to quantify gastro-intestinal protein loss or bleeding. Cobalt 5. High-specific-activity HSA Co is used for brain cancer treatment. Dysprosium 2 h : Used as an aggregated hydroxide for synovectomy treatment of arthritis. Holmium 26 h : Being developed for diagnosis and treatment of liver tumours. Administered as microspheres.

Iodine 60 d : Used in cancer brachytherapy prostate and brain , also diagnostically to evaluate the filtration rate of kidneys and to diagnose deep vein thrombosis in the leg. It is also widely used in radioimmuno-assays to show the presence of hormones in tiny quantities. A strong gamma emitter, but used for beta therapy. Iridium 74 d : Supplied in wire form for use as an internal radiotherapy source for cancer treatment used then removed , e.

Strong beta emitter for high dose-rate brachytherapy. Lead Used especially for melanoma, breast cancer and ovarian cancer. Demand is increasing.

Used in peptide receptor radionuclide therapy PRRT. Lutetium 6. Its half-life is long enough to allow sophisticated preparation for use. It is usually produced by neutron activation of natural or enriched lutetium targets or indirectly by neutron irradiation of Yb Palladium 17 d : Used to make brachytherapy permanent implant seeds for early stage prostate cancer. Emits soft x-rays. Phosphorus 14 d : Used in the treatment of polycythemia vera excess red blood cells.

Beta emitter. Potassium 12 h : Used for the determination of exchangeable potassium in coronary blood flow. Rhenium 3. Beta emitter with weak gamma for imaging.

Samarium 47 h : Sm is very effective in relieving the pain of secondary cancers lodged in the bone, sold as Quadramet. Also very effective for prostate and breast cancer. Scandium 4. It is produced by irradiating calcium to produce Ca which decays to Sc Selenium d : Used in the form of seleno-methionine to study the production of digestive enzymes. Technetiumm 6 h : Used in to image the skeleton and heart muscle in particular, but also for brain, thyroid, lungs perfusion and ventilation , liver, spleen, kidney structure and filtration rate , gall bladder, bone marrow, salivary and lacrimal glands, heart blood pool, infection, and numerous specialized medical studies.

Produced from Mo in a generator. Pure beta emitter and of growing significance in therapy, especially liver cancer. Carbon, Nitrogen, Oxygen, Fluorine These are positron emitters used in PET for studying brain physiology and pathology, in particular for localizing epileptic focus, and in dementia, psychiatry, and neuropharmacology studies. They also have a significant role in cardiology. F in FDG fluorodeoxyglucose has become very important in detection of cancers and the monitoring of progress in their treatment, using PET.

Cobalt d : Used as a marker to estimate organ size and for in-vitro diagnostic kits. Copper 13 h : Used to study genetic diseases affecting copper metabolism, such as Wilson's and Menke's diseases, for PET imaging of tumours, and also cancer therapy. Fluorine min as FLT fluorothymidine , F-miso fluoromisonidazole , 18F-choline: It decays with positron emission, so used as tracer with PET, for imaging malignant tumours. Gallium 78 h : Used for tumour imaging and locating inflammatory lesions infections.

Derived from germanium in a generator. Indium 2. Also for locating blood clots, inflammation and rare cancers. Iodine 13 h : Increasingly used for diagnosis of thyroid function, it is a gamma emitter without the beta radiation of I Iodine 4. Also used to image the thyroid using PET. Kryptonm 13 sec from rubidium 4. Thallium 73 h : Used for diagnosis of coronary artery disease other heart conditions such as heart muscle death and for location of low-grade lymphomas.

It is the most commonly used substitute for technetium in cardiac-stress tests. Radioisotopes in Medicine Updated October Nuclear medicine uses radiation to provide diagnostic information about the functioning of a person's specific organs, or to treat them.

Diagnostic procedures using radioisotopes are now routine. Radiotherapy can be used to treat some medical conditions, especially cancer, using radiation to weaken or destroy particular targeted cells. Sterilization of medical equipment is also an important use of radioisotopes.

Thus, regardless of the number of neutrons they have, all atoms whose nuclei have one proton are hydrogen atoms. All of those with eight protons are oxygen atoms, etcetera. The mass number is the whole number that is closest to the mass expressed in atomic mass units of the atom in question. That is, they have the same atomic number Z but different mass numbers A. For instance, carbon is presented in nature as a mix of three isotopes with mass numbers 12, 13 and 12 C, 13 C and 14 C.

The global amounts of carbon in each are respectively Most chemical elements possess more than one isotope, as is the case of tin, the element with the highest number of stable isotopes. Only 21 elements, like beryllium and sodium, have one single natural isotope.