1,721,067 research outputs found
THE ITALIAN CONTRIBUTION TO EXCITATION FUNCTION MEASUREMENTS FOR TC-99m PRODUCTION BY PROTON BEAMS IRRADIATION
No full textThe radionuclide Tc-99m is the most commonly used radiotracer in nuclear medicine, for diagnostic purpose, due its suitable physics characteristics: T1/2 = 6.0 h, gamma emission at 140.5 keV suited for imaging via single photon emission computed tomography (SPECT) and causes minimal radiation dose to the patient. Since nowadays it is obtained by the Mo-99/Tc-99m generator, with the parent Mo-99 produced by nuclear reactor. The progressively closing process of the nuclear reactors around the world imposes to study alternative routes of Tc-99m production. Among them the direct production by the Mo-100(p,2n)Tc-99m reaction on highly enriched Mo-100 targets appears to be the most promising, even if this kind of production would solve only local or regional demand. In this prospective, due to some evident discrepancies among the excitation functions present in literature, some Laboratories start systematic experimental measurements of the cross sections and a careful analysis of the problems related to the direct production of Tc-99m by this route.
In this contest we have contributed with new measurements and data set to the database of the cross sections, data that now appear more consistent and accurate.
The thin-target yields have been plotted as a function of their average energy into the targets and fitted with the best mathematical function. Its integration gives the calculated thick-target yields, which allow finding the optimized couple of energy irradiation and energy loss inside the thick target to maximize the production. Some considerations about the long lived Tc-99g and the interfering radionuclides have been done
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Cyclotron production and quality control of "high specific activity" radionuclides in "no-carrier-added" form for radioanalytical applications in the life sciences
No full textRadionuclides of very high specific activity A(S)(t) have great relevance for applications in the life sciences. Updated definitions of A(S) are given. The real A(S)(t) must be measured by analytical and radioanalytical techniques. No-carrier-added (NCA) radionuclides have A(S)(NCA) sometimes close to the carrier-free (CF) value A(S)(CF). The accurate knowledge of excitation functions of nuclear reactions vs. ion beam energy is mandatory to maximize A(S)(NCA); the minimization of isotopic dilution factor IDF(t) has been achieved too. A range of accelerator production and radioanalytical QC methods for A(S)(NCA) optimization and determination is presented
Simultaneous production of N.C.A. copper-64 and gallium-67 by deuteron induced nuclear reactions on natural zinc target
No full textPhysical optimization of production by deuteron irradiation of high specific activity 177gLu suitable for radioimmunotherapy
No full textDeuteron-induced nuclear reactions for generation of no-carrier-added (NCA) Lu isotopes were investigated using the stacked-foil activation technique on natural Yb targets at energies up to Ed = 18.18 MeV.
The decay curve of 177Yb, the growth curve of the cumulative (direct and indirect) and the direct production
of 177gLu were determined. The analysis of these curves conducts to the evidence that the predominant route for the production of 177gLu is the indirect reaction 176Yb(d,p)177Yb, which decays to 177gLu. In the spectra
acquired one year from the EOB the γ lines of 177mLu are not evident.
A comparison between the calculated activity of 177gLu produced with a cyclotron and with a nuclear reactor
is given
Determination of 90Sr impurities in [90Y]-labelled avidin-biotine for systemic radionuclide therapy, by liquid scintillation counting
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