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Nowadays there is an increasing demand of engineering nanoparticles – ENPs – thanking the excellent characteristics and properties of the products in which nanoparticles (NPs) are used. On ...

Deuteron-induced nuclear reactions for the generation of 103Pd were investigated using the stacked-foil activation technique on rhodium targets at deuteron energies up to Ed=33MeV. The excitation functions of the reactions 103Rh(d,xn)101,103Pd, 103Rh(d,x)100g,cum,101m,g,102m,gRh and 103Rh(d,2p)103Ru have been measured, and the Thick-Target Yield for 103Pd has been calculated.

Theragnostic medicine is a new integrated therapeutic system which can diagnose, deliver targeted therapy, and monitor the response to therapy. Many of the “neutron-rich” radionuclides suitable for metabolic radiotherapy are produced by nuclear reactor with a very low specific activity (A S). In selected cases, they can be produced by bombardment of targets by charged particle beams in “No Carrier Added Form” with very high A S. If the irradiations are made with deuteron beams some more advantages are obtained, as described in this paper, through 186gRe production, reported as an example.

The use of platinum, palladium and rhodium (Platinum Group Elements - PGEs) and the possibility of exposure to their ultratrace levels is increasing. In fact, the exponential development of metallic PGE-based nanoparticles (100 nm in size) opens extraordinary perspectives in the areas of electrocatalysts and catalytic converters, magnetic nanopowders, polymer membranes, cancer therapy, coatings, plastics, nanofibres and textiles. Like other metal-based nanoparticles, exposure to PGEs nanoparticles may result in a release of ultratrace amounts of Pt, Pd, Rh ions in the body whose metabolic fate and toxicity still need to be evaluated. Furthermore, PGEs can act as allergic sensitizers by acting as haptens and inducing both type I and IV allergic reactions. In this work we studied the in vivo metabolic patterns of ultratrace levels of potent allergens and sensitizers PGE halogenated salts. (191)Pt, (103)Pd and (101m)Rh radioisotopes were prepared via cyclotron irradiation and used for radiolabelling Na2(191)PtCl4, Na2(103)PdCl4 and Na2(101m)RhCl6 salts. These anionic chlorocomplexes were intraperitoneally injected into rats (114 ng Pt kg(-1) bodyweight; 24 ng Pd kg(-1) b.w.; 16 ng Rh kg(-1) b.w.). At 16 h post-exposure, PGEs were poorly but significantly retained in all tissues analysed. Kidneys, spleen, adrenal gland, liver, pancreas and small intestine were the organs with the highest Pt, Pd, Rh concentrations. In the blood 30-35% of (103)Pd and (191)Pt and 10% of (101m)Rh were recovered in the plasma, mainly bound to albumin and to a less extent to transferrin. The hepatic and renal intracellular distribution showed the highest recovery of (191)Pt, (103)Pd and (101m)Rh in the nuclear fraction (liver) and in the cytosol (kidney). Chromatographic separation and ultrafiltration experiments on kidney and liver cytosols showed the strong ability of biochemical macromolecules to bind (191)Pt, (103)Pd and (101m)Rh, and being responsible for the retention of the three elements in the body. The link to macromolecules is the basis for the sensitizing capacity of PGEs.

Proton-induced nuclear reactions for generation of (99)Mo and (99m)Tc radionuclides were investigated using the stacked-foil activation technique on 99.05% enriched (100)Mo targets at energies up to Ep=21MeV. Excitation functions of the reactions (100)Mo(p,x)(99)Mo and (100)Mo(p,2n)(99m)Tc have been measured.

Excitation functions, thin- and thick-target yields for the 181−186gRe and 187W radionuclides were measured by the activation stacked-foil thecnique on natural tungsten foils for deuteron energies up to 18.0 MeV. These cross sections were validated by comparing the experimental results for thick-target yields with those calculated by integration of the thin-target yields. It was found that the maximum 186gRe content by irradiation of natural tungsten is about 55%, a higher value compared with the one found for proton beam, but not sufficient to use natural tungsten for medical purposes yet. Thus, in order to have a higher specific activity A S of 186gRe, the use of enriched 186W target is necessary. Therefore the irradiation of a thick target of enriched 186W by accelerated deuterons was studied and the results for the production of 186gRe were compared with those obtained from the irradiation of the same target by accelerated protons. It was found that the deuteron irradiation is preferable for three reasons: larger yield, less contamination by tantalum radioisotopes and smaller required amount of the target, which simplify the separation of the 186gRe from the target itself.

Deuteron-induced nuclear reactions for generation of no-carrier-added Lu radionuclides were investigated using the stacked-foil activation technique on natural Yb targets at energies up to E(d)=18.18 MeV. Excitation functions of the reactions (nat)Yb(d,xn)(169,170,171,172,173,174g,174m,176m,177g)Lu and (nat)Yb(d,pxn)(169,175,177)Yb have been measured, among them three ((169)Lu, (174m)Lu and (176m)Lu) are reported for the first time. The upper limit of the contamination from the long-lived metastable level (177m)Lu was evaluated too. Thick-target yields for all investigated radionuclides are calculated.

Deuteron-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 E d = 18.18 MeV. The decay curve of 177 Yb, the growth curve of the cumulative (direct and indirect) and the direct production of 177g Lu were determined. The analysis of these curves conducts to the evidence that the predominant route for the production of 177g Lu is the indirect reaction 176 Yb(d,p) 177 Yb, which decays to 177g Lu. In the spectra acquired one year from the EOB the γ lines of 177m Lu are not evident. A comparison between the calculated activity of 177g Lu produced with a cyclotron and with a nuclear reactor is given.

Evaluation of the radioisotopic purity of technetium-99m (99mTc) produced in GBq amounts by proton bombardment of enriched molibdenum-100 (100Mo) metallic targets at low proton energies (i.e. within 15-20 MeV) is conducted. This energy range was chosen since it is easily achievable by many conventional medical cyclotrons already available in the nuclear medicine departments of hospitals. The main motivation for such a study is in the framework of the research activities at the international level that have been conducted over the last few years to develop alternative production routes for the most widespread radioisotope used in medical imaging. The analysis of technetium isotopes and isomeric states (9xTc) present in the pertechnetate saline Na99mTcO4 solutions, obtained after the extraction/purification procedure, reveals radionuclidic purity levels basically in compliance with the limits recently issued by European Pharmacopoeia 9.3 (2018 Sodium pertechnetate (99mTc) injection 4801-3). Moreover, the impact of 9xTc contaminant nuclides on the final image quality is thoroughly evaluated, analyzing the emitted high-energy gamma rays and their influence on the image quality. The spatial resolution of images from cyclotron-produced 99mTc acquired with a mini-gamma camera was determined and compared with that obtained using technetium-99m solutions eluted from standard 99Mo/99mTc generators. The effect of the increased image background contribution due to Compton-scattered higher-energy gamma rays (E γ > 200 keV), which could cause image-contrast deterioration, was also studied. It is concluded that, due to the high radionuclidic purity of cyclotron-produced 99mTc using 100Mo(p,2n)99mTc reaction at a proton beam energy in the range 15.7-19.4 MeV, the resulting image properties are well comparable with those from the generator-eluted 99mTc.

Very high specific activity (AS) 186gRe could be produced by either proton or deuteron cyclotron irradiation on highly enriched 186W target in no-carrier-added (NCA) form, leading to a AS very close to the theoretical carrier free (CF) value of 6.88 GBq lg-1. Thick Target Yields (TTYs), obtained irradiating both thick metal W targets of natural isotopic composition and highly enriched powdered 186W targets, were measured at different particles energies taking into account high accuracy and precision. The evaluation of radionuclidic purities of 186gRe obtained activating highly enriched 186W by both p and d were also carried out and accurately compared. The thin-target excitation functions for all Re (A = 181, 182, 183, 184, 186 and their metastable levels), and W and Ta coproduced radionuclides will be presented elsewhere in deep details., JRC.I.4-Nanobiosciences

(90)Y is one of the most useful radionuclides for radioimmunotherapeutic applications and has a half-life (t(1/2)=64.14h) suitable for most therapeutic applications, beta particles of high energy and decays to a stable daughter. It is significant that (90)Y is available conveniently and inexpensively from a radionuclide "generator" by decay of its parent, (90)Sr. Nevertheless, current and planned clinical applications with [(90)Y] 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 (90)Y solutions. In particular, for the development as a generator, we investigated the percentage of the radio-Sr in the first 8M HNO(3) eluate: in this fraction the concentration of (90)Sr 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 (90)Y in all the fractions containing "only" radio-Sr: (90)Y 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 4mL of Sr-resin which gave better results as a generator and a rapid QC method.

Radioactive solutions of 177g,mLuIIICl3 are used for labeling organic compounds for metabolic radiotherapy and radioimmunotherapy. The labeling process involves Lu in III oxidation state, so the presence of other stable impurities in the same oxidation state could result in an isomorphous dilution of radioactive 177gLu. Samples of 177gLuCl3 were analyzed to quantify the chemical impurities with a special regard for trivalent elements with instrumental neutron activation analysis (INAA), carried out in the research nuclear reactor TRIGA MARK II (GA, USA) of the Universita degli Studi di Pavia, and electrothermal atomic absorption spectroscopy (ET-AAS) (Varian, USA) at LASA.

Thanks to its favorable decay characteristics, 177gLu is finding several applications in nuclear medicine, especially for palliative metabolic radiotherapy of cancer and radioimunotherapy. 177gLu is produced in thermal nuclear reactor either by direct neutron capture 176Lu(n,γ)177(m+g)Lu on either natural or enriched 176Lu target, or by reaction on enriched 176Yb target followed by negatron decay. The latter method does produce a high radionuclidic purity and high specific activity radionuclide in no-carrier-added form, since 177Yb decays solely to the ground state 177gLu. Conversely, the first method does produce a low specific activity 177gLu in carrier-added form,1 contaminated by the long-lived radioisotopic impurity 177mLu. The accurate determination of radionuclidic purity and half-life of 177gLu carried out by HPGe and LSCS is presented in some details.

[186gRe]Re-HEDP is a radiopharmaceutical used for pain palliation in bone metastases from various primary tumors. The negatron emitter with 〈Eβ〉 = 357 keV 186gRe is suitable to irradiate cancer and inflammatory cells, but it needs labeling bis-phosphonates as vectors to reach target tissue. Paper radiochromatography was used to evaluate the radiochemical purity of [186gRe]Re-HEDP in radiopharmaceutical solution as well as in biological samples (serum and urine) from treated patients, in order to follow bone-targeting and excretion. Following the activity concentration in each sample vs. time it is effective to elaborate a bio-kinetic model of the radiopharmaceutical and to optimize administration protocols.

The limited number of radionuclides emitting alpha-particles and their limited availability is discussed. A new alpha-emitter 230U (T1/2 = 20.8 d, 100% a) is suggested and its preparation from thorium target bombarded by accelerated protons (via initial formation of 230Pa (T1/2 = 17.4 d, 8.4% decay to 230U)), or 4He is discussed. The Empire II model was used to calculate the excitation functions for the different products from bombardment of Th by protons. The calculated thick target yield for 230Pa is 0.6 mCi/mA . h, leading to about 24 mCi/mA . h of 230U or about 150 mCi/mA . h in the case of alpha-bombardment.

The short-lived (12.7h half-life) (64)Cu radioisotope is both a beta(+) and a beta(-) emitter. This property makes (64)Cu a promising candidate for novel medical applications, since it can be used simultaneously for therapeutic application of radiolabelled biomolecules and for diagnosis with PET. Following previous work on (64)Cu production by deuteron irradiation of natural zinc, we report here the production of this radioisotope by deuteron irradiation of enriched (64)Zn. In addition, yields of other radioisotopes such as (61)Cu, (67)Cu, (65)Zn, (69m)Zn, (66)Ga and (67)Ga, which were co-produced in this process, were also measured. The evaporation code ALICE-91 and the transport code SRIM 2003 were used to determine the excitation functions and the stopping power, respectively. All the nuclear reactions yielding the above-mentioned radioisotopes were taken into account in the calculations both for the natural and enriched Zn targets. The experimental and calculated yields were shown to be in reasonable agreement. The work was carried out at the Scanditronix MC-40 Cyclotron of the Institute for Health and Consumer Protection of the Joint Research Centre of the European Commission (Ispra site, Italy). The irradiations were carried out with 19.5 MeV deuterons, the maximum deuteron energy obtainable with the MC-40 cyclotron.

High specific activity 64Cu is a radionuclide of increasing interest for PET imaging, as well as systemic and targeted radioimmunotherapy of tumours. The cross sections for production of 64Cu from Zn target of natural isotopic composition were measured in the proton energy range from 141 down to 31 MeV. The stacked-foil technique was used at 160 MeV intersection point of INR proton-LINAC in Troitsk, Russia. Several Ga, Zn, Cu, Ni, Co, V and Mn RNs were detected in Zn targets at the EOB. The activity of no-carrier-added 64Cu was measured through its only gamma-emission of 1346 keV (0.47% intensity). To this purpose, it was necessary to carry out a selective radiochemical separation of Ga RNs from the bulk of irradiated Zn target and other RNs. Theoretical calculations of cross sections were carried out with the CEF model and HMS-ALICE hybrid model codes and are compared with the experimental values.

The nuclear properties of 186g Re make it a useful agent for radionuclide therapy and imaging. The coordination compound ( 186g Re)Re-HEDP has proved to be a successful bone seeking agent for palliation of metastatic bone pain. Chemical, radiochemical and radionuclidic purity of commercial radiopharmaceutical ( 186g Re)Re-HEDP have been checked by means by �- and �-spectrometries, INAA and paper radio- chromatography. The results indicate a good radionuclidic purity, with levels of contamination from the short-lived 188 Re well below the required specifications. After injection of the radiopharmaceutical, the radiochemical measurements conducted in vivo, on biological matrices, blood, plasma and urine, have shown that, entering the systemic circulation, 186g Re dissociates from the bis-phosphonate complex as hydrosoluble ( 186g Re)ReO4 - , and the two chemical species follow different biokinetics.

Many labeled compounds are used as radiopharmaceuticals (RP), for emission imaging and metabolic radiotherapy and contain as labeling agents γ, β-, β+, monochromatic e- and α emitting radionuclides (RN). These labeled compounds very often contain unexpected radionuclidic impurities. Some long-lived isotopic and non-isotopic impurities lead to undesirable radiation doses to the patient and his relatives, as well as to medical/paramedical personnel, other than the general population, due to rad-waste of contaminated specimen and excretion of biological fluids. Use was made of liquid scintillation counting/spectrometry (LSCS) for the detection of tiny amounts of charged particle emitting impurities in RPs labeled with 64Cu, 67Ga, 90Y, 90Sr/90Y, 123I, 153Sm, 177Lu and 201Tl.

Within the radiation protection physical surveillance program of some workers, involved in the decommissioning operations of a nuclear reprocessing plant of the Italian National Agency for New Technologies Energy and Environment, CR Saluggia (ENEA) in the north of Italy, some radiotoxicological analyses, on human urines, have been carried out, in order to determine the possible internal contamination of 241Am. After an in-depth study of a former extraction chromatographic method, based on the use of Microthene-722 supporting HDEHP, a more suitable method has been developed and adopted in our laboratory, based on the use of TRU-resin. This paper reports the results obtained with these two procedures as well as a comparison between them.

A novel method for production of No-Carrier-Added 64 Cu and 66,67 Ga has been developed, based on reactions induced by deuterons up to 19 MeV on Zn target. HPGe and beta (by LSC) spectrometries proved very effective to determine radionuclidic purity of 64 Cu and 66,67 Ga fractions. Experimental specific activity for 64 Cu was measured by ET-AAS and was of the order of 700 MBq · μg −1 . Radiochemical yields for 64 Cu and 66,67 Ga were >80% and >99%.

The radioisotopes of ruthenium (103Ru and 106Ru) are abundant fission products and represent a radiological risk for the population in case of nuclear accidents. Few biokinetic studies have been performed on humans up to now and consequently the current model recommended by ICRP for ruthenium is derived mainly by extrapolation from animal data. The stable isotope 101Ru and proton activation analysis have been used to study the biokinetics of Ru in blood plasma samples taken during 8 studies in three healthy volunteers. The results obtained demonstrated that complexed Ru (in the form of citrate Ru(IV) complexes) is cleared from blood plasma very rapidly (characteristic half time of 17+/-2 min), while inorganic Ru remains longer in the systemic circulation, and is transferred to other organs and/or excreted with a biological half time of 23+/-2h. Good reproducibility of the clearance curves indicated no evidence of inter- or intra-individual variability when the same Ru solution was injected in repeated experiments to different subjects.

Radionuclides 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.

There is much interest in understanding the biokinetics of zirconium in humans due to the potential radiological risk represented by the radionuclide 95Zr and by its daughter 95Nb. Despite the significance of zirconium, few data are available on the actual biokinetics of zirconium in humans. Accordingly the biokinetic model currently recommended by ICRP for this element is based mainly on data from animal experiments. In this study, the use of the stable isotopes 90Zr and 96Zr as tracers has enabled the conduct of 6 biokinetic investigations in 3 healthy volunteers. These studies have provided new valuable information about intestinal absorption and kinetics in blood plasma of zirconium and have been used for the set-up of a more realistic compartmental model with possible applications for dosimetric purposes.

Copper-64 is a radionuclide suitable for labeling of a wide range of radiopharmaceuticals for PET imaging, as well as systemic or local radioimmunotherapy of tumors. Among the possible methods for cyclotron production of No Carrier Added (NCA) 64Cu (61Cu), we investigated the deuteron irradiation on natural Zn target, via (d,axn) and (d,2pxn) nuclear reactions. This paper reports the preliminary results about the experimental determination and theoretical calculation of thin-target excitation functions in the energy range up to 19 MeV for 61Cu, 64Cu, 66Ga, 67Ga, 65Zn and 69mZn. A fast selective radiochemical separation of NCA 64Cu from Zn target and Ga radionuclides, with quality control tests is described too.

Despite the cyclotron production method and the efficiency of the radiochemical procedures adopted, the long-lived radio-isotopic impurity 202Tl is always present in [201Tl]-labelled radio-pharmaceuticals, together with other short-lived impurities like, 200Tl. Rapid determination of the 202Tl impurity, can be achieved using HPGe gamma spectrometry and a detector shielded by a 5 mm thick envelope of lead. In this way, dead-time correction errors, Compton and X-ray background, are very efficiently avoided and suppressed. The same method could be applied routinely in nuclear medicine, to determine the radioisotopic purity of 201Tl by means of an ionisation chamber dose calibrator.

This work describes the method adopted in our laboratories, to produce 94gTc, 95gTc, 95mTc and 96gTc radionuclides via proton-cyclotron irradiation on molybdenum targets of natural isotopic composition. A new set of experimental thin-target excitation functions and "effective" cross-sections for direct natMo(p,xn)(A)Tc [with A = 94, 95, 95, 96] nuclear reactions, with incident proton energy in the range from threshold up to 44 MeV is presented. Some definitions of the equations used and nuclear data traceability are reported. Thick-target yield values were calculated and optimised, by numerical fitting and integration of the measured excitation functions. These values allow optimisation of production yield of one radionuclide, minimising at the same time the yield of the others. Radiochemical separation on NCA technetium radionuclides from both molybdenum target and niobium, zirconium and yttrium radioactive by-products is reported. Quality control tests of the radiotracers were developed for the applications envisaged in environmental metallo-biochemical toxicology.

Both essential and toxic elements are present in the biosphere in different inorganic and organo–metallic forms. Some trace elements like Cr, Cu, Mn, Rb, Se, Tl, V, Zn are essential to human life and are present in human tissues, body fluids, cells and sub-cellular components, bonded to enzymes, proteins, etc. Many trace elements are introduced daily in the body in amounts ranging from ng to μg per kg. A powerful tool to set up analytical procedures, to evaluate the chemical separation yield and to follow the fate of different chemical forms of ultra-trace elements on living organisms is the use of ‘high specific activity’ radioactive tracers (RT). Amongst the more effective RTs for radio-analytical chemistry, there are the short-lived medium γ-energy emitters. A review of the last 25 years in the field of both cyclotron and nuclear reactors producing high specific activity radionuclides in radio-analytical chemistry is presented. As, Au, Cu, Ga, Mn, Np, Pd, Pt, Rb, Rh, Sb, Te, Ti, Tl, V, etc., γ- and β emitting RTs have had interesting applications in the ultra-trace metallo-toxicology field. High-resolution γ-spectrometry by HPGe detection and β spectrometry by liquid scintillation counting, have been used, hyphenated with ‘elemental analysis’ radio-analytical and analytical techniques. The ‘high specific activity’ of the No Carrier Added RTs is the ‘key factor’ of this powerful radio analytical technique.

The increasing concentration of Pt, Pd and Rh in the environment is mainly due to the release of these elements from the catalytic converters of the motorvehicles. This situation makes it necessary to carry out metallotoxicological experiments on both cell cultures and laboratory animals, in order to assess their impact on living organisms after a Long Term and Low Level Exposure (LLE). Both nuclear reactionsnatIr(p,xn) andnatOs(α,xn) were investigated in the energy range up to 45 MeV for protons and 38 MeV for alpha-particles, in order to optimize the irradiation parameters for the production of188,189,191Pt. Several sets of thin- and thick-target excitation functions were determined experimentally by cyclotron irradiation at both Milano and Ispra cyclotrons. This paper reports the irradiation parameters studied and adopted and two radiochemical procedures for the separation of radio-Pt from an Os target, as well as from ruthenium, iridium and gold impurities. These procedures were used to obtain very high specific activity Pt radionuclides in No Carrier Added (NCA) form. Radionuclidic, radiochemical and chemical purity measurements were carred out by the use of several techniques like ψ-spectrometry, ion-exchange radio-chromatography, atomic absorption spectrometry and neutron activation analysis.

The possibility to measure the flux of thermal neutrons by activation of gold of unknown weight using the counts of both 199 Au and 198 Au gamma emission was studied. It can be used for impure gold monitors or when the activated sample has gold in it. The possible interferences are discussed.

First results are given from the comparison of experimental values and model calculations on accelerator-produced high specific activity radionuclides in no-carrier-added (NCA) form. The relevant radioisotopes are: 64 Cu, produced by nat Zn(d, αx n) and nat Zn(d,2p) reactions, for simultaneous positron/negatron metabolic radiotherapy and PET imaging; 66 Ga high-energy positron emitter (4.2 MeV), produced by nat Zn(d, x n) reactions, for metabolic radiotherapy and for PET; 186g Re, produced by 186 W(p,n) and 186 W(d,2n) reactions, for negatron (1.1 MeV) metabolic radiotherapy; 211 At/ 211 Po, produced by 209 Bi( α ,2n) reaction (with spike of gamma emitter 210 At produced by 209 Bi( α ,3n) reaction) and 225 Ac/ 213 Bi/ 213 Po, produced by 226 Ra(p,2n) reaction, both for high-LET radiotherapy.

High Specific Activity Radio-Nuclides (HSARN) are a powerful tool to label a large range of chemical species at very low concentration levels. In order to obtain these radiotracers in a very high specific activity form, it is necessary to optimize the production methods, to separate and purify them from the irradiated target without the addition of inactive carrier, to carry out a series of analytical and radioanalytical tests to determine their “true” specific activity and to verify a series of purity parameters. A review of irradiation methods and nuclear parameters adopted in our laboratories for the preparation of some tens of radiotracers are presented.

High specific activity radiotracers, used in studies related to trace elements and human health, must be characterized by the following specific requirements: (i) high specific activity (activity/mass of isotopic carrier), (ii) high activity concentration (activity/volume or mass of substrate), (iii) radionuclidic, radiochemical and chemical purities, (iv) biological compatibility (physiological pH, sterility and physiological values). For this purpose, selective radiochemical separations and quality control procedures have been developed and tested at our laboratories for the production of several NCA radiotracers.

High specific activity radionuclides are a powerful tool for labeling a large range of inorganic and metallorganic species that are present in the environment at very low concentrations. In order to study the environmental impact of trace elements (TE) on the humans, it is of fundamental importance to carry out both in vitro and in vivo experiments on cell cultures and laboratory animals, with concentrations of these TE representative of the actual long-term and low-level exposures. In order to obtain these radiotracers in a very high specific activity form, it is necessary: (a) to optimize the production method by either charged particle accelerator (normally cyclotron) or nuclear reactor irradiation, (b) to separate and purify them from the irradiated target by chemical or physicochemical methods, without the addition of inactive carriers (i.e., the so-called no carrier added form), (c) to carry out a series of analytical and radioanalytical tests, in order to verify the chemical, radiochemical, and radionuclide purities of the tracer or labeled compound under investigation. Some production, separation, purification, and quality control methods developed for the two cyclotron-produced radionuclides 52gMn and 48V will be presented and discussed.

The use of radiotracers with high specific activity in research on health impact of trace metals overcomes many of the analytical difficulties associated with experimentation carried out at metal levels which are typical of the polluted environment. It allows one to detect and measure ultratrace amounts of metals in biological samples and to follow them into different biochemical compartments, such as subcellular fractions and molecular components. This work shows typical examples of metallotoxicological studies carried out at the JRC-Ispra using radioisotopes with high specific radiactivity produced in the nuclear reactor and in the cyclotron. Applications refer to the use of45Ti,48V,64Cu,95Nb and106mAg in in-vivo and in-vitro studies related to environmental and occupational toxicology research on trace metals.

This chapters deals with production of radionuclides by both neutron bombardment from nuclear reactors and heavy charged accelerated atoms from accelerators. In the case of neutrons, most radionuclides have low specific activity due to the present carrier. The production of carrier-free radionuclides is described. Keywords: radionuclides; carrier-free radionuclides; nuclear reactors; accelerators

In 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.

A range of high specific activity accelerator-produced radionuclides in no-carrier-added (NCA) form, for uses in metabolic radiotherapy and for PET, has been investigated. To this aim it was necessary optimizing the irradiation parameters by determining the excitation functions of the nuclear reactions involved, as needed for the following selective radiochemical separations of the radionuclides of interest. For the NCA radionuclides investigated, the spectrometry measurements, done at LASA-INFN on γ, X and on α spectra are discussed together with the measurements of radionuclidic, radiochemical and chemical purities by analytical and radioanalytical techniques.

The production of no-carrier-added (NCA) alpha-emitter (211)At/(211g)Po radionuclides for high-LET targeted radiotherapy and immunoradiotherapy, through the (209)Bi(alpha,2n) reaction, together with the required wet radiochemistry and radioanalytical quality controls carried out at LASA is described, through dedicated irradiation experiments at the MC-40 cyclotron of JRC-Ispra. The amount of both the gamma-emitter (210)At and its long half-lived alpha-emitting daughter (210)Po is optimised and minimised by appropriate choice of energy and energy loss of alpha particle beam. The measured excitation functions for production of the main radioisotopic impurity (210)At--(210)Po are compared with theoretical predictions from model calculations performed at ENEA.

The radionuclide production for biomedical applications has been brought up in the years, as a special nuclear application, at INFN LASA Laboratory, particularly in co‐operation with the JRC‐Ispra of EC. Mainly scientific aspects concerning radiation detection and the relevant instruments, the measurements of excitation functions of the involved nuclear reactions, the requested radiochemistry studies and further applications have been investigated. On the side of the nuclear data evaluations, based on nuclear model calculations and critically selected experimental data, the appropriate competence has been developed at ENEA Division for Advanced Physics Technologies. A series of high specific activity accelerator‐produced radionuclides in no‐carrier‐added (NCA) form, for uses in metabolic radiotherapy and for PET radiodiagnostics, are investigated. In this work, last revised measurements and model calculations are reviewed for excitation functions of natZn(d,X)64Cu, 66Ga reactions, referring to irradiation...

At the “Radiochemistry Laboratory” of Accelerators and Applied Superconductivity Laboratory, LASA, several production and quality assurance methods for short-lived and high specific activity radionuclides, have been developed. Presently, the irradiations are carried out at the Scanditronix MC40 cyclotron (K=38; p, d, He-4 and He-3) of JRC-Ispra, Italy, of the European Community, while both chemical purity and specific activity determination are carried out at the TRIGA MARK II research reactor of University of Pavia and at LASA itself. In order to optimize the irradiation conditions for platinum radiotracer production, both thin- and thick-target excitation function of natOs(α,xn) nuclear reactions were measured. A very selective radiochemical separation to obtain Pt radiotracers in No Carrier Added form, has been developed. Both real specific activity and chemical purity of radiotracer, have been determined by neutron activation analysis and atomic absorption spectrometry. An Isotopic Dilution Factor (ID...