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The following HTML text is provided to enhance online readability. Many aspects of typography translate only awkwardly to HTML. Please use the page image as the authoritative form to ensure accuracy. Appendix G
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Medical Isotope Production without Highly Enriched Uranium
Appendix G
Glossary
6-day curies: The number of curies present in a shipment of Mo-99 6 days after it leaves a producer’s facilities.
6-day curies per week: The number of 6-day curies supplied in a week.
Barns: A unit of measure of the fission cross section; 1 barn = 1 × 10−24 cm2.
Becquerel (Bq): The SI derived unit of radioactivity, one Becquerel is equal to one radioactive disintegration per second.
Breakthrough: The contamination of Mo-99 in the Tc-99m eluted from the column of a technetium generator that occurs after prolonged use.
Brownfield conversion: Conversion within an existing processing facility or an unused facility with hot cells.
Calandria: A sealed drum-shaped vessel that contains the heavy-water moderator for the reactor. This vessel is penetrated by a series of horizontal fuel channels and vertical channels for control rods.
Casting: The process of melting a metal and pouring into a mold.
Cold rolling: Process in which metal sheets are rolled at room temperature to maintain the metal’s original crystalline structure.
Cold testing: Testing conducted without the use of radioactive material.
Curie (Ci): A unit of radioactivity, defined as 1 Ci = 3.7 × 1010 decays per second.
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Direct-use material: Material that is directly usable in nuclear weapons. Such materials include highly enriched uranium (HEU) and separated plutonium.
Dissolution: The process of putting a material into solution.
Downblend: Dilution of HEU with depleted uranium or natural uranium to convert it into low enriched uranium (LEU).
Drug master file (DMF): A document submitted to the Food and Drug Administration (FDA) by a Mo-99 producer describing the facility in which the Mo-99 is made; the production process itself, including any raw materials used in production; and product test methods, specifications, stability, and release criteria that may be used as a source of information when FDA approval is sought.
Eluting: Recovering an isotope (Tc-99m) by passing a saline solution through the alumina column of the generator.
Enriched uranium: Uranium with a higher concentration of the U-235 isotope than found naturally.
Enrichment: Process used to increase the concentration of the uranium-235 (U-235) isotope in a material relative to U-238.
Fission: Process whereby a large atomic nucleus (such as uranium) is split into two (and sometimes three) smaller nuclei.
Fission cross-section: Probability that a nucleus will capture a neutron and fission, usually expressed in barns.
Fission fragments: Smaller atomic fragments resulting from fission of a large nucleus.
Formula quantities: Special nuclear material in strategic quantities. For HEU this quantity is greater than 5 kg.
Greater-Than-Class-C waste: Radioactive waste that contains concentrations of certain radionuclides above the Class C limits in 10 CFR §61.55.
Greenfield construction: Construction of new facilities for producing and/or processing Mo-99.
Half-life: The time required for a quantity of radioactive material to decay to half of its initial value.
High-level waste: Highly radioactive materials containing fission products and transuranic elements produced as a byproduct of the reactions that occur inside nuclear reactors.
Highly enriched uranium: Uranium enriched to concentrations greater than or equal to 20 percent by weight of U-235.
Hot cell: Shielded workspace for working with highly radioactive materials.
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Hot rolling: Heating metal above its recrystalization temperature before rolling it to form sheets.
Isomeric transition: Radioactive decay process in which the nucleus of a metastable isotope has an elevated energy state and releases this energy by emitting a gamma ray.
Large-scale producer: Producers of Mo-99 who supply more than 1000 6-day curies of Mo-99 per week to the market on a routine basis.
Low enriched uranium: Uranium enriched to concentrations less than 20 percent by weight of U-235.
Medical isotopes: Class of radioactive isotopes (radioisotopes) that have unstable nuclei and emit radiation. This radiation is used for medical imaging and treatment.
Neutron capture: Process involving the capture of neutrons by an atomic nucleus to form a heavier nucleus.
Neutron flux: Measure of the intensity of neutron radiation, defined as the number of neutrons crossing a unit area of a square centimeter in one second (neutrons/cm2-s).
New drug application (NDA): A written application to the Food and Drug Administration seeking approval to sell a pharmaceutical in the United States.
Perfusion: Delivery of arterial blood to biological tissue.
Perfusion reserve: Capacity of flow through a blood vessel system in an organ under a stress or stimulus.
Regional producers: Producers who supply Mo-99 for indigenous or regional use in less than large-scale quantities.
Significant quantity: Approximate quantity of material from which the possibility of manufacturing a nuclear explosive device (i.e., a device that can achieve a prompt critical mass) cannot be excluded.
Special nuclear materials: Fissile material or material that is capable of sustaining a chain reaction of nuclear fission. It includes plutonium and uranium enriched in the isotopes U-233 or U-235.
Stenosis: Abnormal narrowing of a blood vessel.
Supplemental new drug application (sNDA): Additional written documentation submitted for approval by the FDA when a producer makes major changes to the process or raw materials it uses to make a pharmaceutical.
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Target: Material containing U-235 that is designed to be irradiated in a nuclear reactor.
Target cladding: Target encapsulation of aluminum or stainless steel that serves to protect the chemically reactive uranium metal or alloy and to contain the fission products produced during irradiation.
Target meat: Uranium-bearing material in the target.
Tc-99m kits: Chemicals (e.g., pharmaceutical agent, chelating compound, and saline solution) used to formulate a radiopharmaceutical to which Tc-99m is added.
Technetium generator: Device used to store Mo-99 and extract its decay product Tc-99m.
Technetium generator curies: Calibrated quantity of Mo-99 based on the number of curies that are contained in the generator on the day of or day after its delivery to the radiopharmacy, hospital, or clinic.
Thermal neutron: Low-energy neutron of about 0.025 electron volts at room temperature.
Tracer testing: Evaluation of the separations methods and processing of targets using very small amounts of radioactive material.