Excitation functions of natZn(p,x) nuclear reactions with proton beam energy below 18 MeV

We measured the excitation functions of ^natZn (p,x) reactions up to 17.6 MeV, using the stacked-foils activation technique. High-purity natural zinc (and copper) foils were irradiated with proton beams generated by an 18 MeV isochronous cyclotron. Activated foils were measured using high-purity Ge gamma spectroscopy to quantify the radionuclides ⁶¹Cu, ⁶⁶Ga, ⁶⁷Ga, and ⁶⁵Zn produced from the reactions. Thick-target integral yields were also deduced from the measured excitation functions of the produced radioisotopes. These results were compared with the published literature and were found to be in good agreement with most reports, particularly those most recently compiled.     

Excitation functions of proton-induced reactions on natFe and enriched 57Fe with particular reference to the production of 57Co

Excitation functions of the reactions ^natFe(p,xn)^55,56,57,58Co, ^natFe(p,x)⁵¹Cr, ^natFe(p,x)⁵⁴Mn, ⁵⁷Fe(p,n)⁵⁷Co and ⁵⁷Fe(p,α)⁵⁴Mn were measured from their respective thresholds up to 18.5 MeV, with particular emphasis on data for the production of the radionuclide ⁵⁷Co (T_1/2=271.8 d). The conventional stacked-foil technique was used, and the samples for irradiation were prepared by an electroplating or sedimentation process. The measured excitation curves were compared with the data available in the literature as well as with results of nuclear model calculations. From the experimental data, the theoretical yields of the investigated radionuclides were calculated as a function of the proton energy. Over the energy range E_p=15→5 MeV the calculated yield of ⁵⁷Co from the ⁵⁷Fe(p,n)⁵⁷Co process amounts to 1.2 MBq/μA h and from the ^natFe(p,xn)⁵⁷Co reaction to 0.025 MBq/μA h. The radionuclidic impurity levels are discussed. Use of highly enriched ⁵⁷Fe as target material would lead to formation of high-purity ⁵⁷Co.     

Activation cross sections of α-particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: Production of 178W/178mTa generator

In the frame of a systematic study of charged particle production routes of medically relevant radionuclei, the excitation function for indirect production of ^178mTa through ^natHf(α,xn)¹⁷⁸W–^178mTa nuclear reaction was measured for the first time up to 40 MeV. In parallel, the side reactions ^natHf(α,x)^{179,177,176,175}W, ^{183,182,178g,177,176,175}Ta, ^{179m,177m,175}Hf were also assessed. Stacked foil irradiation technique and γ-ray spectrometry were used. New experimental cross section data for the ^natTa(d,xn)¹⁷⁸W reaction are also reported up to 40 MeV. The measured excitation functions are compared with the results of the ALICE-IPPE, and EMPIRE nuclear reaction model codes and with the TALYS 1.4 based data in the TENDL-2013 library. The thick target yields were deduced and compared with yields of other charged particle ((p,4n), (d,5n) and (³He,x)) production routes for ¹⁷⁸W.     

Excitation function of the 64Ni(α,p)67Cu reaction for production of 67Cu

The excitation function of the ⁶⁴Ni(α,p)⁶⁷Cu reaction was measured from threshold up to 24 MeV in order to investigate the possibility of production of the β⁻-emitting therapeutic radioisotope ⁶⁷Cu (T_1/2=61.9 h). Two stacks of thin metallic self-supporting foils of ⁶⁴Ni (enrichment 77.8%) prepared by electrolytic deposition were irradiated by α-particle beams. The radioactivity was determined via HPGe detector γ-ray spectrometry. Some ⁶⁷Ga activity (which emits the same γ-rays as ⁶⁷Cu), formed via the ^natCu(α,x)⁶⁷Ga process on trace copper impurity in the Ni foils, was also observed. Corrections were done for ⁶⁷Ga activity contribution and for the ⁶⁷Cu activity escape fraction from the thin Ni-foil. The maximum cross section of the ⁶⁴Ni(α,p)⁶⁷Cu reaction amounts to 34 mb at 22 MeV. The experimental results were compared with theoretical predictions. The integral yield of ⁶⁷Cu at 24 MeV α-particle energy, calculated from the excitation function, amounts to 544 KBq/μAh (48.5 MBq/μA at saturation). It is thus a low-yield reaction.     

The natBr(p,x)73,75Se nuclear processes: a convenient route for the production of radioselenium tracers relevant to amino acid labelling

A possible route for the production of no-carrier-added (n.c.a.) ⁷³Se (T_1/2=7.1 h) and ⁷⁵Se (120 d) is introduced. d,l-2-Amino-4-([⁷³Se]methyl-seleno) butanoic acid (d,l-[⁷³Se]selenomethionine) with an overall radiochemical yield of >40% could be prepared via a 3-step polymer-supported synthesis after successful separation of ⁷³Se from KBr targets. Excitation functions for the ^natBr(p,x) ^72,73,75Se processes were measured from threshold up to 100 MeV utilizing pellets of pressed KBr. Targets were irradiated at the NAC cyclotron with proton beams having primary energies of 40.4, 66.8 and 100.9 MeV. The calculated ⁷³Se yield (EOB) for 1 h irradiation in 1 μA of beam at the optimum proton energy range of 62→42 MeV is 81.4 MBq (2.2 mCi), and the calculated ⁷⁵Se yield (EOB) for the overall range 62 MeV→threshold for the same irradiation conditions is 0.97 MBq (0.026 mCi).     

Cross section measurements of proton and deuteron induced reactions on natural europium and yields of SPECT-relevant radioisotopes of gadolinium

The existing cross section data of the ^natEu(d,x) and ^natEu(p,x) reactions relevant for the production of ^147,149Gd were expanded up to 70.9 MeV and 44.8 MeV, respectively. Integral yields of radiogadolinium were calculated, showing production rates higher than for the earlier proposed irradiation of highly enriched ¹⁴⁴Sm with α- or ³He-particles. The formation of radioisotopic impurities like ¹⁵¹Gd (T_1/2=124 d) and ¹⁵³Gd (T_1/2=240 d) was below 5%. Production of ^147,149Gd using enriched europium is also discussed.     

Cyclotron production of 67Ga(III) with a tandem natGe−natZn target

Production of ⁶⁷Ga(III) at the National Accelerator Centre is by proton bombardment of a ^natZn target, and uses 15−20 h of cyclotron beam time per production. A study was undertaken to use a tandem ^natGe−^natZn target to produce the same amount of ⁶⁷Ga, but using less beam time (7−8 h). ⁶⁷Ga(III) was separated from the tandem target material by a method based on acid dissolution of the target and chromatography on an organic polymer resin (Amberchrom™ CG−71cd) containing no ion exchange groups. The separated ⁶⁷Ga(III) has high radionuclidic purity and complies with the British and US Pharmacopoeia requirements for chemical purity.     

Calculations for the excitation functions of 3-26 MeV proton reactions on 66Zn, 67Zn and 68Zn.

Calculation of excitation functions of 66Zn(p,n)66Ga, 66Zn(p,n + p)65Zn, 66Zn(p,2n)65Ga, 67Zn(p,2n)66Ga, 68Zn(p,n)68Ga, 68Zn(p,2n)67Ga natZn(p,xn)66Ga and natZn(p,xn)67Ga reactions has been carried out using the statistical and pre-equilibrium nuclear reaction models in the 3-26 MeV energy range. The calculational results are compared with the reported measurements and evaluations.     

Investigation of production of the therapeutic radioisotope 165Er by proton induced reactions on erbium in comparison with other production routes

The excitation function of the ^natEr(p,xn)¹⁶⁵Tm reaction resulting in production of ¹⁶⁵Er was measured up to 70 MeV by activation of stacked foils practically for the first time. The theoretical interpretation is based on the results of the ALICE-IPPE and EMPIRE-II codes. From the measured experimental cross section data integral production yield was calculated and compared with experimental integral yield data reported in the literature. Different production routes of the therapeutic radioisotope ¹⁶⁵Er were compared.     

Calculation of induced reactions of 3He-particles on natSb in 10–34 MeV energy range

Calculations for the excitation functions of the ¹²¹Sb(³He, xn) ^121,122,123I, and ¹²³Sb(³He xn) ^{122,123,124,125}I reactions have been carried out using statistical and pre-equilibrium nuclear reaction models in 10−34 MeV energy range. These excitation functions have been used to derive the excitation functions of the ^natSb(³He, xn)^121,123,124I reactions and compared with reported measurements. For studying the improvement with measurements two values of the diffuseness parameter a_w equal to 0.9 and 0.7 fm have been used in the calculations. The dependence of pre-equilibrium calculations on the initial exciton numbers has also been considered.     

Separation of no-carrier-added 93,94,94m,95,96Tc from 7Li induced natural Zr target by liquid–liquid extraction

Charged particle activation was carried out on ^natZr foil by 42.5 MeV ⁷Li beam to produce ^{93,94,94m,95,96}Tc radionuclides. No-carrier-added (nca) technetium radionuclides were separated from co-produced ^90,96Nb and bulk Zr employing liquid–liquid extraction with the help of anion exchanger trioctylamine (TOA) diluted in cyclohexane and HCl. Bulk Zr was monitored by spiking ^88,89Zr produced by 20 MeV proton induced reaction on ^natY target. The optimum separation was achieved at 0.1 M TOA and 0.01 M HCl. Technetium radionuclides were recovered from the TOA phase by stripping with 0.1 M DTPA (diethylene triamine pentaacetic acid) dissolved in NaOH.     

Yield and purity of 82Sr produced via the natRb(p,xn)82Sr process

The recently reported cross-section data for the production of ⁸²Sr via the ^natRb(p,xn)⁸²Sr process were evaluated. For the ^natRb(p,xn)⁸⁵Sr process, cross-sections were measured experimentally over the proton energy range of 25–45 MeV, a region where very few data existed. An evaluation of the recently published data on the formation of ⁸⁵Sr was then also performed. From the recommended data curves, the integral yields of the desired radionuclide ⁸²Sr and the impurity ⁸⁵Sr were calculated. Yields were also determined experimentally over several energy ranges using thick ^natRbCl targets. The experimental and calculated yields were found to be in agreement within 15%. These integral tests add confidence to the evaluated cross-section data. For the production of ⁸²Sr, an incident proton energy of 60 MeV or above is recommended; the ⁸⁵Sr impurity then corresponds to <20%.     

Performance of a 62Zn/62Cu microgenerator in kit-based synthesis and delivery of [62Cu]Cu–ETS for PET perfusion imaging

The performance of a commercially produced ⁶²Zn/⁶²Cu microgenerator system, and an associated kit-based radiopharmaceutical synthesis method, was evaluated for clinical site production of [⁶²Cu]Cu–ETS (ethylglyoxal bis(thiosemicarbazonato)copper(II)), an investigational agent for PET perfusion imaging. Using 37 generators, containing 1.84±0.23 GBq ⁶²Zn at 9:00 AM on the day of clinical use, a total of 45 patient doses of [⁶²Cu]Cu–ETS (672±172 MBq) were delivered without difficulty. ⁶²Cu elution yields were high (approximately 90%), accompanied by extremely low ⁶²Zn breakthrough (<0.001%). Radiopharmaceutical preparation, from the start-of-elution to time-of-injection, consumed less than five minutes. The ⁶²Zn/⁶²Cu microgenerator was a dependable source of short-lived positron-emitting ⁶²Cu, and the kit-based synthesis proved to be rapid, robust, and highly reliable for “on-demand” delivery of [⁶²Cu]Cu–ETS for PET perfusion imaging.     

Activation cross-sections of proton induced reactions on natural Ni up to 65 MeV

Production cross-sections of the ^natNi(p,x)^60,61Cu, ^56,57Ni, ^55,56,57,58Co nuclear reactions were measured in five experiments up to 65 MeV by using a stacked foil activation technique. The results were compared with the available literature values, predictions of the nuclear reaction model codes ALICE-IPPE, TALYS-1.4, and extracted data from the TENDL-2012 library. Spline fits were made on the basis of selected data, from which physical yields were calculated and compared with the literature values. The applicability of the ^natNi(p,x)⁵⁷Ni, ⁵⁷Co reactions for thin layer activation (TLA) was investigated. The production rate for ⁵⁵Co was compared for proton and deuteron induced reactions on Ni.     

Effective separation method of 64Cu from 67Ga waste product with a solvent extraction and chromatography

A simple chemical process with a solvent extraction was investigated as an effective separation method for ⁶⁴Cu radionuclide from waste production, which is collected as solution after extracting ⁶⁷Ga and recovering ⁶⁸Zn target materials. For the production of radionuclide ⁶⁷Ga, the enriched ⁶⁸Zn material electroplated on Cu backing plate is usually exposed to energetic protons. The protons produce ⁶⁷Ga including other radionuclides, such as ⁵⁷Ni, ^57,55Co, ^64,67Cu by several nuclear reactions. After extracting ⁶⁷Ga and recovering ⁶⁸Zn through several steps of chemical processes, the residual solution is usually discarded even though it contains other species of radioisotopes. In this study, a simple chemical process having a high separation efficiency of ⁶⁴Cu from the waste solution was investigated. With this method, a promising radiotracer as a diagnostic in PET and a therapeutic in radio-immunotherapy, ⁶⁴Cu was estimated to be produced as high as 1,200 mCi at EOB within 3 h chemical processing after extraction of ⁶⁷Ga and ⁶⁸Zn.     

Thermal diffusion of 67Ga from irradiated Zn targets

Gallium-67 is a cyclotron produced radionuclide and ⁶⁷Ga-citrate complex scans are performed in a variety of applications in Nuclear Medicine. The aim of this study was to evaluate a new method for the chemical separation of ⁶⁷Ga from Zn targets. The method has 2 steps, first the thermal diffusion of ⁶⁷Ga with concentrated acetic acid and then purification by cation exchange in ammonium medium. The final ⁶⁷Ga solution was obtained in 0.1 mol L⁻¹ HCl with the desirable high purity.     

Cation exchange separation of 61Cu2+ from natCo targets and preparation of 61Cu–DOTA–HSA as a blood pool agent

An improved method for isolation of ⁶¹Cu²⁺ from a ^natCo target using cation exchange was developed. ⁶¹Cu²⁺ was eluted from a cation exchange resin column by 0.2 M HCl with 90% acetone, while Co²⁺ remained on the column. The whole separation process was completed within 50 min at more than 72% yield. The Co²⁺ impurity level in ⁶¹Cu²⁺ solution was reduced to less than 0.1 ppm. Highly pure ⁶¹Cu²⁺ solution was then applied to prepare ⁶¹Cu–1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)–human serum albumin (HSA) which showed good blood pool imaging properties.     

Measurements of 186Re production cross section induced by deuterons on natW target at ARRONAX facility

IntroductionThe ARRONAX cyclotron, acronym for “Accelerator for Research in Radiochemistry and Oncology at Nantes Atlantique” is a new facility installed in Nantes, France. A dedicated program has been launched on production of innovative radioisotopes for PET imaging and for β − and α targeted radiotherapy using protons or α particles. Since the accelerator is also able to deliver deuteron beams up to 35 MeV, we have reconsidered the possibility of using them to produce medical isotopes. Indeed, in some cases, the use of deuterons allows higher production yield than protons.Methods¹⁸⁶Re is a β − emitter which has chemical properties close to the widely used ^99mTc and has been used in clinical trials for palliation of painful bone metastases resulting from prostate and breast cancer. ¹⁸⁶Re production cross section has been measured between 9 and 23 MeV using the ARRONAX deuteron beam and the stacked-foil technique.A novelty in our work is the use of a monitor foil behind each ^natW target foil in order to record efficiently the deuteron incident flux and energies all over the stack relying on the International Atomic Energy Agency (IAEA) recommended cross section of the ^natTi(d,x)⁴⁸V reaction. Since a good optimization process is supposed to find the best compromise between production yield and purity of the final product, isotope of interest and contaminants created during irradiation are measured using gamma spectrometry.ResultsOur new sets of data are presented and compared with the existing ones and with results given by the TALYS code calculations. The thick target yield (TTY) has been calculated after the fit of our experimental values and compared with the IAEA recommended ones.ConclusionsPresented values are in good agreement with existing data. The deuteron production route is clearly the best choice with a TTY of 7.8 MB/μAh at 30 MeV compared to 2.4 MBq/μAh for proton as projectile at the same energy. The TALYS code gives satisfactory results for ^183,186Re isotopes.     

Excitation function of 3He-particle induced nuclear reactions on natural palladium

Excitation functions of ³He-particle induced nuclear reactions on natural palladium were measured using the standard stacked foil technique and high resolution γ-ray spectroscopy. From their threshold energies up to 27 MeV, cross-sections for ^natPd(³He,x)^{103,104,105,106m,110m,111,112}Ag and ^natPd(³He,x)^{104,105,107,111m}Cd reactions were measured. The nuclear model codes TALYS-1.4, and EMPIRE-3.1 were used to describe the formation of these products. The present data were compared to theoretical results and to the available experimental data. Integral yields for some important radioisotopes were determined.     

New calculation of excitation functions of proton-induced reactions in some medical isotopes of Cu, Zn and Ga.

The new calculations on the excitation functions of 61Ni(p,n)61Cu, 62Ni(p,n)62Cu, 64Ni(p,n)64Cu, 63Cu(p,2n)62Zn, 63Cu(p,n)63Zn, 65Cu(p,n)65Zn, 66Zn(p,n)66Ga, 67Zn(p,2n)66Ga, 67Zn(p,n)67Ga and 68Zn(p,n)68Ga reactions have been carried out in the 5-30 MeV proton energy range. The calculations involve the cascade exciton model, preequilibrium nuclear reaction model and exciton model. The calculated results are compared with the experimental data taken from the literature.