Labeling radionuclides

Decay products of the principal radionuclides used in tracer technology (see Table 1) are not themselves radioactive. Therefore, the primary decomposition events of isotopes in molecules labeled with only one radionuclide / molecule result in unlabeled impurities at a rate proportional to the half-life of the isotope. Eor and H, impurities arising from the decay process are in relatively small amounts. Eor the shorter half-life isotopes the relative amounts of these impurities caused by primary decomposition are larger, but usually not problematic because they are not radioactive and do not interfere with the application of the tracer compounds. Eor multilabeled tritiated compounds the rate of accumulation of labeled impurities owing to tritium decay can be significant. This increases with the number of radioactive atoms per molecule. 

Pfutzner, W. et al.. Intraoperative labeling of sentinel lymph nodes with a combination of vital dye and radionuclide tracer results in sentinel lymph node-positive patients, J. Deutsch. Dermatol. Ges., 4, 229, 2006. 

However, problems are encountered in production of rhenium radionuclides and work is being done to increase the yields of the radionuclides to meet urgent demands for their use in therapy. Moreover, rhenium is not as reactive as technetium. This situation makes rhenium chemistry somewhat specific - optimum conditions in the preparation of rhenium complexes or in antibody labeling using bifunctional ligands must be identified. 

SC-18 Standards and Measurements of Radioactivity for Radiological Use SC-24 Radionuclides and Labeled Organic Compounds Incorporated in Genetic Material... 

Singh et al. (2006) also used cycloaddition to prepare carbon nanotubes containing indium labeled diethylenetriamine pentaacetic acid (DTPA) derivatives (Figure 15.17). In the initial modification, a SWNT was derivatized to contain a primary amine at the end of a short PEG spacer. The resultant water-soluble nanotube then was reacted with DTPA to create a metal chelating group at the end of the chain. Subsequent loading of the chelate with mIn created a radionuclide-SWNT complex for in vivo biodistribution studies. 

Wilbur, D.S. (1992) Radiohalogenation of proteins An overview of radionuclides, labeling methods, and reagents for conjugate labeling. Bioconjugate Chem. 3, 433-470. 

A specialized application of microwave-assisted organic synthesis involves the preparation of radiopharmaceuticals labeled with short-lived radionuclides, particularly for use in positron emission tomography [70-72]. This represented an excellent application of microwave technology, where the products must be prepared quickly and in high radiochemical yield, on a small scale. 

The development of PET radiopharmaceuticals labeled with generator-produced radionuclides has facilitated greater use of PET in clinical nuclear medicine. The 68Ge/68Ga parent/daughter pair is ideal as a source of PET radiopharmaceuticals as a result of the favorable half-lives of both the parent and daughter radionuclides (43-45). The 271 days half-life of the 68Ge parent... 

PET and SPECT are both functional imaging methods that use externally administered radionuclide-labeled substances to image in vivo physiological processes in 3-D space 944... 

The first lecture given by Tomas Hokfelt, who pioneered anatomical studies based on amine fluorescence, was entitled, Neuroanatomy for the Neurochemist while the second lecture given by Louis Sokoloff, who invented the methodology of functional brain imaging originally based on metabolism of radionuclide labeled-2-deoxyglucose, was entitled Neurochemistry for the Neuroanatomist . The history and further information... 

A protocol for the light microscope radioautography of Lilium longiflorum pollen tubes labeled with [14C]-proline follows. This protocol, which does not require tissue embedding in paraffin or Paraplast, can be modified for paraffin-embedded tissues see Chapter 2). Thus, by employment of the protocol, together with the preceding introductory information in this chapter, one should be able to derive a protocol applicable to the cells or tissue in question. The performance of the protocol requires approval of an institution s Radiation Safety Officer. An inventory of incoming radionuclides, their presence in secondary containers, and their waste must be carefully recorded. The waste must be further broken down into solid waste, liquid waste, and animal carcasses to aid in its proper disposal. 

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