Terminology, Quantities, and Units Concerning Production and Applications of Radionuclides in Radiopharmaceutical and Radioanalytical Chemistry

Terminology, Quantities, and Units Concerning Production and Applications of Radionuclides in Radiopharmaceutical and Radioanalytical Chemistry

The current editions of the IUPAC Orange and Gold Books do not adequately cover the definition of terms used in nuclear and radiochemistry, radioanalytical, and radiopharmaceutical chemistry, and related nuclear sciences and technologies. A detailed analysis of relevant textbooks, journals, and IUPAC recommendations, published in the last decades, has been carried out by a task group of the Analytical Chemistry Division. The task group has found that many terms and definitions should be clarified or modified and then disseminated through the scientific and industrial communities.

This new project will update and improve the terminology, quantities, and units concerning production and application of radionuclides in radiopharmaceutical and radioanalytical chemistry. The task group will pay particular attention to the critical discussion of several concepts (e.g., carrier, specific activity, activity concentration, isotopic exchange, and speciation of carrier forms) related to production of radionuclides and labeled chemical entities (i.e., radiopharmaceutical compounds).^1-3 The resulting document will also explain the relationships between these quantities and the applications of radioactivity in the life sciences, in bio- and nano-technologies, and radioanalytical techniques.^4,5

High specific activity radionuclides and labelled compounds are of increasing relevance and demand in the field of radiodiagnostics by γ-scintigraphy, single-photon emission tomography (SPECT, SPET), and positron emission tomography (PET, i.e., more properly the detection of annihilation radiation of positron emitters). While the molecular imaging techniques, based on emission of γ photons of nuclear origin, do provide information on in-vivo biochemistry, pharmacokinetic, and metabolism of drugs and labeled chemical entities, other complementary imaging techniques like computerized tomography (CT, CAT) and nuclear magnetic resonance (NMRi, MRi) provide mainly morphological data about the body compartment or organ under investigation. Fusion imaging techniques like PET/CT, SPET/CT and PET/MRi do increase further the performances of molecular imaging techniques and are of increasing use in medical departments, both for research and clinical purposes.

Another field of relevant interest to this task group is metabolic radiotherapy, immunoradiotherapy, targeted radiotherapy of tumors and degenerative pathologies, by compounds labelled with beta and Auger emitters, high-LET alpha emitters and short-lived in-vivo radionuclide generators.

The main aspects of terminology that will be discussed in the document are as follows:

• glossary of terms, quantities, units of radioactivity, and related quantities and their definitions in SI (and other obsolete systems of units)

• radionuclide production by ion accelerator, thermal/fast nuclear reactor, fast neutron generator

• radioanalytical and radiopharmaceutical chemistry laboratory techniques

• radioanalytical methods and nuclear analytical techniques and features

• labelling of chemical species, drugs, and radiopharmaceutical compounds

• quality control/assurance of radionuclides and labelled compounds

• interaction of radiation with matter; radiation protection and dosimetry, laboratory safety

• fields of application include radiodiagnostics by direct techniques; radiodiagnostics by fusion techniques; molecular imaging; metabolic radiotherapy with radiopharmaceutical compounds; immunoradiotherapy with beta, Auger, and alpha emitters; and targeted radiotherapy

• exhaustive and updated list of literature, nuclear databases, and international/national e-links

The project is of interest to other IUPAC Divisions: Physical and Biophysical, Inorganic, Organic and Biomolecular, Macromolecular, Analytical, Environmental, Human Health, Nomenclature, as well as CHEMRAWN, Chemistry and Industry, and Chemistry Education. Relations with IAEA, IUPAP, ISO, BIPM, ICRP, ICRU, EU-JRC, NIST, WHO and other relevant bodies are envisaged or already established.

The new document will be implemented using XML-based files, which can be easily analyzed without the use of customized software products and can be read by several text editors. The dissemination plan will consist of the following:

• review of the results of the project on the main journals devoted to nuclear, radioanalytical, and radiopharmaceutical chemistry

• presentation of the results at international conferences and workshops on nuclear chemistry, radioanalytical chemistry, radiopharmaceutical chemistry, and related technologies, as well as radiation and radionuclide metrology

• strong recommendation to the editors of scientific journals to adopt the updated nomenclature

• public information about the impact of nuclear related technologies on human health and quality of life (i.e., visibility of nuclear related sciences and technologies)

References

1. A.P. Wolf, T.J. Tewson, M.J. Welch, J. Nucl. Med., 22 (1981): 392-393.

2. J.J.M. de Goeij, M.L. Bonardi, How do we define the concepts specific activity, radioactive concentration, carrier, carrier-free, no-carrier-added?, MARC-VI, April 2003, Kailua-Kona, USA; J. Radioanal. Nucl. Chem., in press.

3. M.L. Bonardi, J.J.M. de Goeij, How do we ascertain specific activities in no-carrier-added radionuclide preparations?, ibidem, in press.

4. M.L.Bonardi, C. Birattari, F. Groppi, E. Sabbioni, Appl. Radiat. Isot., 57 (2002): 617-635.

5. M.L. Bonardi, F. Groppi, H.S. Mainardi, Microchem. J., 73 (2002): 153-166.

For more information, contact the Task Group Chairman Mauro L. Bonardi <mauro.bonardi@mi.infn.it>.

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