No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Simulation of the indirect reaction 92Mo(α, 2n)94Ru→m94Tc using TALYS and GEANT4 nuclear codes
Abstract
Radioisotope 94mTc is a favorable positron emitter radioisotope in nuclear medicine that can be used for PET. Production of 94mTc via indirect reaction 92Mo(α, 2n)94Ru → 94mTc was predicted by SRIM, TALYS,and GEANT4 codes. SRIM and GEANT4 codes were employed to calculate the range of alpha particles into enriched 92Mo and to estimate the thickness of the target. Further, the GEANT4 and the TALYS codes were used to investigate the cross-section and production yield of the 92Mo(α, 2n)94Ru reaction. Four model methods were utilized to compute the cross-section by TALYS-1.95 code. The simulated results were compared with experimental values that reported by F.O. Denzler and found to be in good agreement between them. This observation indicates that the SRIM, the GEANT4 and the TALYS codes are suitable tools for prediction of producing radioisotopes via various reactions.
... Diverse parts of science such as medical physics, accelerator induced radiation, neutron and gamma shielding, environment radiation, and microdosimetery areas of science could be studied by GEANT4 code. Flexibility of the selection of physics list, the input parameters and output list and files for the users is the best feature of GEANT4 code [59][60][61][62][63]. ...
Study the shielding properties of materials against charged and non-charged particles is a vital issue in the present era. In this paper, GEANT4, MCNP, XCOM, Phy-X/PSD, EpiXS, and NGCal programs were applied to evaluated shielding characterization of the B2O3-PbO-SiO2-Dy2O3 glass system against photons with the energy range of 10–100 keV. LAC, MAC, HVL, TVL, MFP, Zeff, Neff, and Zeq parameters were computed using the mentioned software. The simulated values were compared to each other, which the good compatibility between them was shown. As can be seen from the figures and tables, with increasing the amount of Dy2O3, MAC and LAC values rise. Therefore, dy5 with the most values of MAC was selected as the most favorable shield against X-ray photons.
Numerous studies have focused on the use of accelerators for production of 99m Tc, but all of these investiga- tions have been performed at low-level currents. In this research, for the first time, we have constructed a high power level natural Mo target for production of 99m Tc radioisotope using cyclotrons. A high purity natural molybdenum target (130 mg/cm 2 ), suitable for proton beam power level of several kilowatts, has been constructed using a thermal spray coating method. The target was irradiated in a Cyclone30 accelerator using 160 μA of 25 MeV proton beam energy for 1000 μA-h. The activity of produced 99m Tc was measured as 2.75 Ci. The technetium radionuclides produced were extracted using an MEK organic phase, followed by preparation of Tc-BRIDA as a radio-labelled kit sample. Animal biodistribution studies have been performed in rats. After administration of the radio-labelled Tc-BRIDA in rats, we observed most of the radioactivity accumulated in intestine as expected for IDA derivatives. The results of measurements show a successful production of Tc radionuclides (including 99m Tc) in the bombarded target and subsequent labelling of the kit with Tc. It is anticipated that the developed coating method for the production of high power Mo targets using enriched 100 Mo and a proton beam of about 1 mA is capable of producing about 100 Ci of 99m Tc per irradiated target. The developed high power Mo target, if constructed using enriched 100 Mo, could be a practical method for a large-scale production of 99m Tc for local applications near cyclotron facilities.
The goal of this work was to test whether an antibody-based agent approved for use as a single-photon-emitting imaging agent when radiolabeled with technetium-99m could be labeled comparably with a positron-emitting nuclide, technetium-94m. "Instant kits" containing lyophilized NP-4 antibody Fab' fragment of an anticarcinoembryonic antigen IgG (CEA-Scan) from the same manufactured lot were reconstituted with either Tc-99m or Tc-94m, as solutions of sodium pertechnetate in isotonic saline solution. Radioanalyses of the labeled Fab' fragments by size-exclusion high-performance chromatography and TLC were carried out. Equivalent results were obtained for radioimmunoconjugates when each was analyzed with both methods. Facile incorporation of Tc-94m into tumor-targeting Fab' antibody fragments will enable investigation of such agents for tumor-specific imaging using positron emission tomography.
The main goal of this study is the production investigation of the ¹¹¹In as a diagnostic and mighty radionuclide in nuclear medicine especially in the Single Photon Emission Computed Tomography (SPECT) technique. Excitation functions based on four main phenomenological level density models were evaluated for the induced reactions; namely, ¹⁰⁹Ag(α,2n), ¹¹⁰Cd(d,n),¹¹¹Cd(p,n),¹¹²Cd(p,2n),natCd(p,xn) and natCd(d,xn) using the TALYS-1.8 and EMPIRE-3.2 nuclear codes. Furthermore, simulation code was used for the mentioned processes and, also, the ¹¹¹In production yield predictions in each reaction were done. Finally, in order to certify the above calculation outcomes, a comparison with the existing data which were taken from EXFOR database was implemented.
In this work, the differential cross-sections of 151Eu(γ,n)150Eu and 153Eu(γ,n)152Eu photonuclear reactions in the giant dipole resonance region (GDR) were considered by theoretical models available in Talys 1.8 code. Isomeric ratios of these two reactions induced by bremsstrahlung with end-point energies in (GDR) region were then simulated using the calculated cross-section in combination with Monte-Carlo simulation using Geant4 toolkit based code which was implemented to simulate bremsstrahlung and photonuclear reaction. Moreover, a simple model was added into Geant4 for populating multi-isomeric states. The theoretical results were compared with the experimental data from the existing literature to examine the validity of the theoretical modes.
Excitation functions based on level density were calculated for proton-induced on yttrium-89 using the TALYS-1.8 code. Hence, production cross-section of the ⁸⁹Y(p,x)86,88,89gZr, 86g,87g,88gY, 85gSr, and 84gRb were computed up to 50 MeV. In this study, the constant temperature model alongside the Fermi Gas model (CGCM) was employed as a default model. For this reason, the a-parameter as an essential parameter in the Fermi Gas formula was modified to obtain the best result. Besides, the Back-shifted Fermi Gas Model (BSFGM) and the Generalized Superfluid Model (GSM) are presented to the deliberation. The outcomes of cross-sections were compared with the experimental data approaching regarding desired consequences.
The excitation functions for reaction residues populated via In115(p,p)115mIn, In115(p,pn)114mIn, In115(p,p2n)113mIn, In113(p,p)113mIn, In115(p,nα)111mCd, In115(p,3n)¹¹³Sn and In113(p,n)¹¹³Sn channels were measured over the proton energy range of 8–22 MeV using stacked foil activation technique. Theoretical analysis of the data were performed within the framework of two statistical model codes EMPIRE-3.2 and TALYS-1.8. Isomeric cross section ratio for isomeric pairs Inm,g115, Inm,g114, Inm,g113, S113nm,g and Cdm,g111 were determined for the first time. The dependence of isomeric cross section ratio on various factors are analysed.
The radionuclide zirconium-89 can be employed for the positron emission tomography (PET). In this study (89)Zr excitation function via (89)Y(p,n)(89)Zr reaction was calculated by the TALYS-1.8 code based on microscopic level density model. The formation of (89)Zr was simulated using the Monte Carlo simulation code MCNPX to calculate the integral yield in the (89)Y target body for threshold up to 40MeV incident-proton energy. The target thickness was based on calculation of the stopping power using the SRIM-2013 code matched to any incident-proton energy. The production yield of the (89)Zr simulated with the Monte Carlo method for the (89)Y(p,n)(89)Zr, (89)Y(d,2n)(89)Zr, (nat)Sr(α,xn)(89)Zr and (nat)Zr(p,pxn)(89)Zr reactions and the results were in good agreement with published experimental results for the optimum energy range. An experimental yield of 53.1MB/µA for the 15MeV proton-induced on Y2O3 powder as a disk-target obtained for 1h irradiation at the AMIRS cyclotron.
A useful approach to optimize of radioisotope production is the use of Monte Carlo simulations prior to experimentation. In this paper, the GEANT4 code was employed to calculate the saturation yields of 62,63Zn from proton-induced reactions of natural copper, enriched ⁶³Cu and ⁶⁵Cu. In addition, the saturation yields of the investigated radio-nuclides were calculated using the stopping power from the SRIM-2013 and reported experimental data for cross sections. The simulated saturation yields were compared with experimental values. Good agreement between the experimental and corresponding simulated data demonstrated that GEANT4 provides a suitable tool for radionuclide simulation production using proton irradiation.
The use of radioisotopes in nuclear medicine is essential for diagnosing and treating cancer. The optimization of their production is a key factor in maximizing the production yield and minimizing the associated costs. An efficient approach to this problem is the use of Monte Carlo simulations prior to experimentation. By predicting isotopes yields, one can study the isotope of interest expected activity for different energy ranges. One can also study the target contamination with other radioisotopes, especially undesired radioisotopes of the wanted chemical element which are difficult to separate from the irradiated target and might result in increasing the dose when delivering the radiopharmaceutical product to the patient.
The aim of this work is to build and validate a Monte Carlo simulation platform using the GEANT4 toolkit to model the solid target system of the South Australian Health and Medical Research Institute (SAHMRI) GE Healthcare PETtrace cyclotron. It includes a GEANT4 Graphical User Interface (GUI) where the user can modify simulation parameters such as the energy, shape and current of the proton beam, the target geometry and material, the foil geometry and material and the time of irradiation.
The paper describes the simulation and presents a comparison of simulated and experimental/theoretical yields for various nuclear reactions on an enriched nickel 64 target using the GEANT4 physics model QGSP_BIC_AllHP, a model recently developed to evaluate with high precision the interaction of protons with energies below 200 MeV available in Geant4 version 10.1. The simulation yield of the ⁶⁴Ni(p,n)⁶⁴Cu reaction was found to be 7.67 ± 0.074 mCi·μA⁻¹ for a target energy range of 9–12 MeV. Szelecsenyi et al. (1993) gives a theoretical yield of 6.71 mCi·μA⁻¹ and an experimental yield of 6.38 mCi·μA⁻¹. The ⁶⁴Ni(p,n)⁶⁴Cu cross section obtained with the simulation was also verified against the yield predicted from the nuclear database TENDL and compared to experimental yield obtained from literature.
The 63Zn is an important positron emitting radionuclide for using in PET. The theoretical models, TALYS-1.6 and EMPIRE-3.2.2, were used to construct the excitation functions for proton, deuteron, and alpha particle induced reactions on different targets. The results were compared with the reported experimental data and with the theoretical values obtained from the TENDL-2014 database. Stopping powers were calculated using SRIM 2013 code for each reaction. The 63Zn production yields were estimated using calculated cross sections and stopping powers. It has been verified that 63Cu(p,n)63Zn reaction is the optimum 63Zn production route.
Excitation functions were measured by the stacked-foil technique for 94Mo(p, xn)94m94g,93m,93m, gTc-reactions from threshold to 18.4 MeV. Thin samples of 93.9% enriched 94Mo powder of 10 mm diameter and 3 6 mg/cm2 thickness were prepared via a Sedimentation method. Thick target yields of 94mTc were calculated from the measured excitation function, and the levels of radiotechnetium impurities were determined experimentally. The Optimum proton energy range for the production of 94mTc was found to be Ep = 13→7 MeV, with the expected thick target yield of 54 mCi (2 GBq)/μAh. The isomeric cross section ratio for the isomeric pair 94m, gTc is discussed.
The radionuclide 99Mo, which has a half-life of 65.94 h was produced from 238U(γ, f) and 100Mo(γ, n) reactions using a 10 MeV electron linac at EBC, Kharghar Navi-Mumbai, India. This has been investigated since the daughter product 99mTc is very important from a medical point of view and can be produced in a generator from the parent 99Mo. The activity of 99Mo was analyzed by a γ-ray spectrometric technique using a HPGe detector. From the detected γ-rays activity of 140.5 and 739.8 keV, the amount of 99Mo produced was determined. For comparison, the amount of 99Mo from 238U(γ, f) and 100Mo(γ, n) reactions was also estimated using the experimental photon flux from 197Au(γ, n)196Au reaction. The amount of 99Mo from the detected γ-lines is in agreement with the estimated value for 238U(γ, f) and 100Mo(γ, n) reactions. The production of 99Mo activity from 238U(γ, f) and 100Mo(γ, n) reactions is a relevant and novel approach, which provides alternative routes to 235,238U(n, f) and 98Mo(n, γ) reactions, circumventing the need for a reactor. The viability and practicality of the 99Mo production from the 238U(γ, f) and 100Mo(γ, n) reactions alternative to 235,238U(n, f) and 98Mo(n, γ) reactions has been emphasize. An estimate has been also arrived based on the experimental data of present work to fulfill the requirement of DOE.
The Geant4 toolkit provides a wide set of alternative models to describe the electromagnetic interaction of photons with matter. The photon cross-sections that are used by the Geant4 electromagnetic models have been compared to external reference libraries (NIST, EPDL97, SANDIA) for several elements and compounds. The agreement of the Geant4 cross-section with the reference data has been quantified by means of statistical analysis. In particular, the cross-sections of all the Geant4 photon models are in statistical agreement with the NIST database, with the exception of Rayleigh scattering. A critical discussion is presented for those cases where a disagreement is found. (C) 2010 Elsevier B.V. All rights reserved.
Excitation functions for the 100Mo(p,2n)99mTc, 100Mo(p,pn)99Mo and 98Mo(p,γ)99mTc nuclear reactions were determined using 97.4 and 99.5% isotopic enrichment of 100Mo and 98Mo, respectively. The irradiations were performed on three different cyclotrons with overlapping data points from 6 to 65 MeV. The optimum energy range for the 100Mo(p,2n)99mTc reaction is 22→12 MeV with a peak at ∼17 MeV and maximum cross section of ∼200 mb. Over this energy range the production yield of 99mTc amounts to 11.2 mCi (415 MBq)/μA h or 102.8 mCi (3804 MBq)/μA at saturation. There is no serious radionuclidic impurity problem. Production of 99Mo is not viable due to the low cross section (∼130 mb) over the proton energy range of 30 to 50 MeV. The 98Mo(p,γ)99mTc reaction was found to have a cross section of <0.2 mb over the proton energy range studied. The earlier assignment of this reaction channel as a potential route for production of 99mTc with a medical cyclotron is refuted in this study. Countries that do not have access to fission molybdenum-99 for the 99Mo→99mTc generator, could consider use of a >17 MeV proton energy cyclotron for regional production of 99mTc.
The cyclotron-based (100)Mo(p,2n)(99m)Tc transformation has been proposed as a viable alternative to the reactor based (235)U(n,f)(99)Mo→(99m)Tc strategy for production of (99m)Tc. Despite efforts to theoretically model the amount of ground-state (99g)Tc present at end of bombardment for the (p,2n) reaction, experimental validation has yet to be performed. The co-production of (99g)Tc may have important implications in both the subsequent radiopharmaceutical chemistry and patient dosimetry upon injection.
To determine the extent of (99g)Tc co-production, we have experimentally measured the (100)Mo(p,x)(99)Mo, (99m)Tc, and (99g)Tc excitation functions in the 8-18 MeV range using a combination of natural abundance and 97.42% enriched (100)Mo foils along with γ-ray spectrometry and ICP-MS. Although the excitation functions for production of (99)Mo and (99m)Tc have been presented previously in the literature, to the best of our knowledge, this work presents the first experimental evaluation of the (100)Mo(p,2n)(99g)Tc excitation function.
From the experimental cross-section measurements, the (99m)Tc production yields and (99m)Tc/(99m+g)Tc nuclei ratio were calculated for various thick target irradiation conditions. Results suggest that TBq quantities of (99m)Tc can be achieved with a (99m)Tc/(99m+g)Tc nuclei ratio that is on par with the current (99)Mo/(99m)Tc generator standard eluted at a 24-h frequency.
These findings suggest that the cyclotron production of (99m)Tc may be a feasible alternative to the current reactor-based production strategy.
Excitation functions of α-particle induced nuclear reactions on highly enriched 92Mo: comparative evaluation of production routes for 94mTc
- Denzler