16 research outputs found
Accelerator and nuclear reactor production, radiochemical processing and quality control of high specific activity radionuclides for applications in the life sciences
No full textAfter 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
Proposal of Mo-100(gamma,n)Mo-99 reaction study using Compton backscattering gamma-ray beams at INFN-LNF
No full textThe shortage on the world market of 99Mo -> 99mTc “generators” for medical radiodiagnostics, due to the recent and incoming shut-down of several isotope production nuclear reactors, does request the development of new production methods based on other kind of radiation sources, like charged particle accelerators (either fast light ions or electrons).
The Thomson backscattering of a Joule-class laser pulse colliding with a ~ 900 MeV electron beam, can be a source of ultra-focused ps pulses of X-rays, in the 5-20 MeV energy range, with much narrower bandwidth and higher spectral density. A possible upgrade to these energies of a 500 keV Thomson Source being commissioned in 2011 at the Laboratori Nazionali di Frascati (LNF) of INFN, is being considered, with an anticipated operation by the year 2013
On the photon self-absorption correction for thin-target-yields vs. thick-target-yields in radionuclide production
No full textIn the experimental determination of activity of low gamma energy emitters by HPGe spectrometry, after cyclotron irradiation of thick targets of high Z elements, it is mandatory to introduce a correction for gamma-ray self-absorption in the target. The amount of this correction is substantial in order to provide a statistically acceptable agreement with the thick-target-yield data obtained by integration of the experimental thin-target-yield data that are very slightly affected by self-absorption instead
Misura indoor del radon-222 in locali del Comune di Coriza, Albania - Radon-222 indoor measurements in Korca municipality's areas, Albania
No full textIl progetto RADIOLAB, riguardante la divulgazione della cultura scientifica in materia di radioattività per sfatare dei taboo e avvicinare i giovani a queste tematiche, viene svolto in Italia dal 2004. Negli ultimi anni ha travalicato i confini nazionali coinvolgendo giovani albanesi in particolare gli studenti del Liceo di Themistokli Germenji di Corizia. In questo articolo viene presentato il loro lavoro sperimentale relativo alla misura della concentrazione di radon-222 in alcune strutture peculiari quali la propria scuola e il Municipio del Comune di Corizia. Questo progetto ha dimostrato quanto potente sia la sua valenza non solo per le discipline scientifiche che coinvolge ma anche come strumento di utilizzo dell’italiano come lingua veicolare.The RADIOLAB project, concerning the dissemination of scientific culture in the field of radioactivity to dispel taboo and bring young people closer to these issues, has been carried out in Italy since 2004. In recent years it has crossed national borders by involving Albanian young people, in particular students of Themistokli Germenji high school in Korce. This article presents their experimental work relating to the measurement of radon-222 concentration in some peculiar structures such as their own school and the Municipality of Korce. This project has shown how powerful its value is not only for the scientific disciplines
it involves but also as a tool for using Italian as a transmissive language
Produzione e impiego ottimizzati di radionuclidi per diagnostica e terapia in medicina nucleare
No full textRapid determination of Sr-90 impurities in freshly generator eluted Y-90 for radiopharmaceutical preparation
No full textY-90 is one of the most useful radionuclides for radioimmunotherapeutic applications and has a half-life (t(1/2) = 64.14 h) suitable for most therapeutic applications, beta particles of high energy and decays to a stable daughter. it is significant that Y-90 is available conveniently and inexpensively from a radionuclide "generator" by decay of its parent, Sr-90. Nevertheless, current and planned clinical applications with [Y-90] labelled compounds employ activity levels that cannot be readily obtained from an in-house generator, but from commercial sources. We have evaluated Eichrom's Sr-resin, either as an "in-house" generator or as a fast QC method for analysis of Y-90 solutions.
In particular, for the development as a generator, we investigated the percentage of the radio-Sr in the first 8 M HNO3 eluate: in this fraction the concentration of Sr-90 must be smaller than 10(-5)% (recommendations of the International Commission on Radiological Protection). For evaluation as a rapid QC method, we analyzed the concentration of Y-90 in all the fractions containing "only" radio-Sr: Y-90 should not be present in these eluates. After the collection of beta(-) and gamma spectra and analysis of them, we concluded that commercial Sr-resin minicolumn cannot give us the results expected; we developed an in-house system loaded with 4 mL of Sr-resin which gave better results as a generator and a rapid QC method
