Nuclear chemistry radioactive tracers

The only respect in which the hot atom chemistry of organometallic compounds has so far been applied to other fields of study is in the area of isotope enrichment. Much of this has been done for isolation of radioactive nuclides from other radioactive species for the purpose of nuclear chemical study, or for the preparation of high specific activity radioactive tracers. Some examples of these applications have been given in Table II. The most serious difficulty with preparation of carrier-free tracers by this method is that of radiolysis of the target compound, which can be severe under conditions suited to commercial isotope production, so that the radiolysis products dilute the enriched isotopes. A balance can be struck in some cases, however, between high yield and high specific activity (19, 7J),... 

Note For additional information on use of radioactive tracers in energetic materials, see also Nuclear Tracers in Explosives Chemistry in Vol 8, N210-L to N219-L... 

Nuclear chemistry (radiochemistry) has now become a large and very important branch of science. Over four hundred radioactive isotopes have been made in the laboratory, whereas only about three hundred stable isotopes have been detected in nature. Three elements —technetium (43), astatine (85), and promethium (61), as well as some trans-uranium elements, seem not to occur in nature, and are available only as products of artificial transmutation. The use of radioactive isotopes as tracers has become a valuable technique in scientific and medical research. The controlled release of nuclear energy promises to lead us into a new world, in which the achievement of man is no longer limited by the supply of energy available to him. 

In 1966, in an article in NUCLEONICS, with TerPogossian, I wrote, The most important radioactive tracer in biological research is reactor-produced Carbon- 14,but it has never been widely used in nuclear medicine. The introduction of Carbon-11, Nitrogen-13, Qxygen-15 and Fluorine-18 revolutionized the study of regional chemistry in the Uving human body. 

The separation procedure most suitable for californium isotopes generated in accelerators may not be the same as that used for californium produced in reactor targets. In some accelerator experiments the desired californium isotopes may be physically separated via recoil mechanisms, which simplifies the rapid separations required for short-lived isotopes. The need for nuclear or radioactive purity, as opposed to chemical purity, will also affect the particular separative processes to be used. A considerable amount of information on californium chemistry was determined using tracer levels of californium. The major purification schemes for californium at the tracer level involved ion-exchange techniques to separate californium from other transcurium elements. 

Excellent, comprehensive treatments of the principles and fundamentals of nuclear activation analysis - including applications fundamentals - are found in the following five consecutive chapters in the first edition of Treatise on Analytical Chemistry Finston (1971a) (Radioactive and isotopic methods of analysis nature, scope, limitations, and interrelations) Finston (1971b) (Nuclear radiations characteristics and detection) Crouthamel and Heinrich (1971) (Radiochemical separations) Seaman (1971) (Tracer techniques) and Guinn (1971) (Activation analysis). A series of seven similarly comprehensive chapters appeared in the updated second edition Lieser (1986), (Fundamentals of nuclear activation and radioisotopic methods of analysis) Herpers... 

The section Radioactive Methods in volume 9 of the Treatise on Analytical Chemistry (Kolthoff and Elving 1971) discusses radioactive decay, radiation detection, tracer techniques, and activation analysis. It has a brief but informative chapter on radiochemical separations. A more recent text. Nuclear and Radiochemistry Fundamentals and Applications (Lieser 2001), discusses radioelements, decay, counting instruments, nuclear reactions, radioisotope production, and activation analysis in detail. It includes a brief chapter on the chemistry of radionuclides and a few pages on the properties of the actinides and transactinides. 

Compounds labeled with isotopes have played an important role in chemistry, biology, and medicine since they were first used as tracers by Hevesey. - Both stable - and radioactive isotopes were utilized in early investigations, but the situation changed dramatically with the invention of the cyclotron by Lawrence in 1930 and the construction of the nuclear reactor by Fermi in 1942 that enabled access to radioisotopes on a regular basis. Radioisotope use in medicine was also accelerated by advances in radiation-detection techniques. The development of single-photon emission computerized tomography (SPECT) " and positron emission tomography revolutionized... 

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