After the deployment of the “radiotracer technique” in the 1920s by the Hungarian born radiochemist György von Hevèsy, it was clearly understood that both natural and artificial radiotracers would be a powerful tool for investigating inorganic, organic and biological systems. The powerfulness of the modern applications of this technique is based on the high specific activity of tracer itself (short half-life and low content of either isotopic or molecular carrier). According to IUPAC terminology, the specific activity AS is defined as the activity of a specified radionuclide to the mass of isotopic carrier (Bq•kg-1) in a well specified chemical form, or as the activity to the amount of substance of a specified labeled compound (Bq•mol-1). This SI quantity must not be confused with the concentration of activity CA, which is the activity of the radionuclide to the mass or volume of radioactive specimen (Bq•kg-1, Bq•m-3). A very high AS radiotracer (MBq•ug-1 to TBq•ug-1) has the advantage that the system under investigation is not “perturbed” by the addition of radiotracer itself, in particular for living organisms: cell cultures, animals, humans, leading to detailed information on biokinetics of uptake and release of different chemical species (radiopharmaceticals) in diverse body compartments or districts, without interfering with the natural metabolism of these systems. In order to assure the reliability of the investigation, it is mandatory carrying out an accurate quality control on both the radionuclide and labelled species, that means the determination of the followings: radionuclidic purity, radiochemical purity, chemical purity, specific activity, activity concentration and - in case of living organisms - biological purity as well. Moreover, all previous parameters tend to spoil with time, and the experimental evaluation of these phenomena must be investigated as well. The accelerator produced radionuclides belong to the neutron poor region of the table of nuclides (the red side of beta stability valley), conversely the nuclear reactor produced ones belong to the neutron rich side (the blue area). Of course, for higher atomic numbers, a series of useful alpha emitters (yellow area) can be produced by accelerator irradiation too. A few radionuclides of very high atomic number, characterized by spontaneous fission decay find increasing applications in the life sciences. The red nuclides (positron and EC decay) are used extensively for radiodiagnostics purposes onto humans, while the blue ones (negatron emitters) are used more and more for the metabolic radiotherapy of tumours and in minor extent for other pathologies. In recent years the yellow radionuclides are being used for therapeutic purposes and there are increasing investigations about the possibility to use low energy Auger emitters for hitting efficiently the DNA, with irreversible double and multiple strand breaks, after internalization into cell nuclei.

Accelerator and nuclear reactor production, radiochemical processing and quality control of high specific activity radionuclides for applications in the life sciences / M. Bonardi, F.M. Groppi Garlandini. ((Intervento presentato al convegno Laboratori Nazionali di Legnaro : seminario tenutosi a Villi meeting room, Padova nel 2008.

Accelerator and nuclear reactor production, radiochemical processing and quality control of high specific activity radionuclides for applications in the life sciences

M. Bonardi
Primo
;
F.M. Groppi Garlandini
Ultimo
2008-12

Abstract

After the deployment of the “radiotracer technique” in the 1920s by the Hungarian born radiochemist György von Hevèsy, it was clearly understood that both natural and artificial radiotracers would be a powerful tool for investigating inorganic, organic and biological systems. The powerfulness of the modern applications of this technique is based on the high specific activity of tracer itself (short half-life and low content of either isotopic or molecular carrier). According to IUPAC terminology, the specific activity AS is defined as the activity of a specified radionuclide to the mass of isotopic carrier (Bq•kg-1) in a well specified chemical form, or as the activity to the amount of substance of a specified labeled compound (Bq•mol-1). This SI quantity must not be confused with the concentration of activity CA, which is the activity of the radionuclide to the mass or volume of radioactive specimen (Bq•kg-1, Bq•m-3). A very high AS radiotracer (MBq•ug-1 to TBq•ug-1) has the advantage that the system under investigation is not “perturbed” by the addition of radiotracer itself, in particular for living organisms: cell cultures, animals, humans, leading to detailed information on biokinetics of uptake and release of different chemical species (radiopharmaceticals) in diverse body compartments or districts, without interfering with the natural metabolism of these systems. In order to assure the reliability of the investigation, it is mandatory carrying out an accurate quality control on both the radionuclide and labelled species, that means the determination of the followings: radionuclidic purity, radiochemical purity, chemical purity, specific activity, activity concentration and - in case of living organisms - biological purity as well. Moreover, all previous parameters tend to spoil with time, and the experimental evaluation of these phenomena must be investigated as well. The accelerator produced radionuclides belong to the neutron poor region of the table of nuclides (the red side of beta stability valley), conversely the nuclear reactor produced ones belong to the neutron rich side (the blue area). Of course, for higher atomic numbers, a series of useful alpha emitters (yellow area) can be produced by accelerator irradiation too. A few radionuclides of very high atomic number, characterized by spontaneous fission decay find increasing applications in the life sciences. The red nuclides (positron and EC decay) are used extensively for radiodiagnostics purposes onto humans, while the blue ones (negatron emitters) are used more and more for the metabolic radiotherapy of tumours and in minor extent for other pathologies. In recent years the yellow radionuclides are being used for therapeutic purposes and there are increasing investigations about the possibility to use low energy Auger emitters for hitting efficiently the DNA, with irreversible double and multiple strand breaks, after internalization into cell nuclei.
radiotracers ; high specific activity ; radiopharmaceuicals ; quality control test ; radionuclidic purity ; radiochemical purity ; chemical purity ; specific activity ; activity concentration ; biological purity
Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)
Settore CHIM/03 - Chimica Generale e Inorganica
INFN-LNL
Accelerator and nuclear reactor production, radiochemical processing and quality control of high specific activity radionuclides for applications in the life sciences / M. Bonardi, F.M. Groppi Garlandini. ((Intervento presentato al convegno Laboratori Nazionali di Legnaro : seminario tenutosi a Villi meeting room, Padova nel 2008.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/62416
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