Isotopes for Medicine and the Life Sciences (1995) / Chapter Skim
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2 ENRICHED STABLE ISOTOPES
2 ENRICHED STABLE ISOTOPES
Pages 19-34
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From page 19... ...
Similar labeling of nearly any compound is theoretically possible by synthesizing it with large quantities of an isotope that is relatively rare in nature. In the last two decades the use of enriched stable isotopes has offered substantial advantages to scientists and clinicians involved in the rapid growth of research on human body composition, energy balance, protein turnover, and fuel utilization (Whitehead and Prentice, 19911.
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From page 20... ...
science and technology of an isotope monopoly controlled by a single financially distressed foreign source. CURRENT APPLICATIONS IN MEDICINE AND PHYSICAL AND LIFE SCIENCES In many areas of research, the need for enriched stable isotopes is as vital as the need for pure chemicals (Friedlander and Wagner, 19821.
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From page 21... ...
Some of the most important contemporary uses of enriched stable isotopes involve investigations of the human metabolism of calcium, zinc, magnesium, and other cations needed by humans. The minimum dietary requirements of metals needed in trace amounts (e.g., selenium, molybdenum, copper, and rubidium)
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From page 22... ...
. composltlon · Environmental pollutant toxicity studies · Noninvasive studies of chromium metabolism and human requirements · Adult onset diabetes mechanisms · Noninvasive studies of copper metabolism and requirements · Studies of congenital disorders and body kinetics in gastrointestinal diseases · Investigation of role in maintaining integrity of tissue such as myocardium · In viva magnetic resonance studies · Vitamin research · Chemical reaction mechanisms Iron-54, -57, -58 · Metabolism, energy expenditure studies · Conditions for effective iron absorption and excretion · Research to develop successful interventions for anemia · Metabolic tracer studies to identify genetic iron control mechanisms
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From page 23... ...
ENRICHED STABLE ISOTOPES TABLE 2-1 Continued 23 Stable Isotope Uses Krypton-78, -80, -82, -84, -86 Lead-204, -206, -207 Lithium-6 Magnesium-25, -26 Molybdenum-94, -96, -97, - 100 Nickel-58, -60, -61, -64 Nitrogen- 15 Oxygen- 17 Oxygen- 18 Rubidium-85, -87 Selenium-74, -76, -77, -78, -80, -82 Sulfur-33, -34 Vanadium-51 Xenon- 129 Zinc-64, -67, -68, -70 · Diagnosis of pulmonary disease . - Isotope dilution to measure lead levels in blood · Sodium and renal physiology · Membrane transport · Psychiatric diseases · Noninvasive studies of human nutrition requirements, metabolism, and absorption · Kinetic studies of heart disease and vascular problems Extrinsic labeling of food for determination of human nutrition requirements · Noninvasive measurement of human consumption and absorption · Large-scale uptake studies in plants · Whole body protein turnover, synthesis, and catabolism · Amino acid pool size and turnover · Metabolism of tissue and individual proteins · Studies in structural biology · Cataract research · Noninvasive, accurate, and prolonged measurement of energy expenditures during everyday human activity · Lean body mass measurements · Obesity research · Comparative zoology studies of energy metabolism · Potassium metabolism tracer · Mental illness research · Bioavailability as an essential nutrient ~ Human genome research and molecular studies · Nucleotide sequencing studies · Diabetes, bioavailability, and metabolism · Brain metabolism studies · Magnetic resonance imaging · Noninvasive determination of human zincrequirements · Metabolic diseases, liver disease, and alcoholism · Nutritional requirements and utilization studies
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From page 24... ...
Overall, nearly 40 percent of the world's enriched stable isotope sales are small purchases for research purposes. Medicine, primarily radiopharmaceutical companies, accounts for about half of all purchases, and industrial users account for the remaining 10 percent.
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The calutrons represent a unique but aged resource for the production of enriched stable isotopes, and no other facility that could duplicate this capability exists in the United States. Operation of the calutrons requires a staff of 35, however (Collins, 1993)
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Plasma separation could be used for the direct production of enriched stable isotopes or to enrich material as feedstock for the calutrons. The plasma separation process is only about half as efficient as the process performed by the calutrons in terms of product purity, but it is 300 times faster.
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From page 27... ...
From its beginnings in the Manhattan Project, the U.S. government's enriched stable isotope program operated with modest federal subsidy (approximately $2 million annually in the late 1980s)
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, and at high levels of enrichment. Although many of these technologies are still in the research and development stage-even, in some cases, in a conceptual stage they should be studied and developed as potential contributors to the future supply of enriched stable isotopes that will be needed by the research community in the United States and elsewhere.
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From page 29... ...
The process may be capable of providing enriched stable isotopes for more than half of the elements of the periodic table, although annual operating costs for the LLNL plant might be as high as $20 million to $30 million (Stern, 19931. AVLIS achieves isotope separation by the use of intense laser beams tuned to selectively ionize specific isotopes.
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From page 30... ...
3. An adequate supply of enriched stable isotopes currently exists for the production of most biomedically significant radionuclides, but DOE inventory of enriched stable isotopes is being depleted through sales without replacement.
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From page 31... ...
RECOMMENDATIONS A dependable supply of enriched stable isotopes controlled by the United States is crucial for research, therapy, diagnosis, and other applications. In the near term this means that the electromagnetic separation capabilities of the Oak Ridge National Laboratory calutrons should be maintained in standby mode until a more cost-effective source of enriched stable isotopes can be developed, or external sources fail to meet demand.
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From page 32... ...
1993. Atomic Vapor Laser Isotope Separation.
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