Level structure of 99Tc by inelastic scattering and proton stripping

The ⁹⁸Mo(³He, d)⁹⁹Tc and ⁹⁹Tc(d, d') reactions have been used to study the levels of of ⁹⁹Tc. Spin-parity assignments are made for nearly all states below 1.5 MeV excitation. Strong j-dependence is noted for l = 1 transitions in the proton stripping reaction, making possible several new spin assignments. The inelastic scattering data on ⁹⁹Tc are compared to similar data on ⁹⁸Mo, and are found to be in agreement with a coupling scheme based on a shell model with good seniority.     

The hyperfine field of99Tc in iron

The magnetic hyperfine field at⁹⁹Tc impurities in Fe has been measured to be ¦H _hf¦=325 (7) kGauss at 298 °K. The technique of time-differential perturbed angular correlations on the 181 keV state of⁹⁹Tc was used.     

Detection and dosimetry of gamma ray emitted from thallium-201 and technetium-99m based on chemiluminescence technique

This report describes the detection and dosimetry of gamma ray emitted from Thallium-201 (²⁰¹Tl) and Technetium-99m (^99mTc) based on chemiluminescence technique. H₂O₂ produced by two gamma emitter radioisotopes of ²⁰¹Tl and ^99mTc were quantitatively measured by chemiluminescence method. Upon producing H₂O₂ in a luminol alkaline solution, in the presence of diperiodatocuprate, as catalyst a chemical reaction was accrued and consequently the emitted light was measured. The determined H₂O₂ concentration was correlated with the gamma ray detection and dosimetry. The sensitivity of chemiluminescence technique for ²⁰¹Tl and ^99mTc dosimetry was determined to be 0.20 and 0.08 MBq/l (Mega Becquerel per liter) respectively (R.S.D. = %5, N = 3). The plotted calibration curves showed detection limits of 3.24 and 1.76 MBq/l for ²⁰¹Tl and ^99mTc, respectively.     

Low-lying states in99Tc populated by (3He,d) reaction in98Mo

The proton stripping reaction⁹⁸Mo(³He,d)⁹⁹Tc is studied with 18 MeV³He ion beam. The out-going deuterons from the reaction are analysed using an Enge magnetic spectrograph. The experimental angular distributions are compared with distorted-wave-Born-approximation calculations, andl-values and spectroscopic factors are obtained. Many of the previous spin-parity assignments for the low-lying states in⁹⁹Tc are confirmed and new ones are made. The proton configuration for the ground state of⁹⁸Mo is deduced.     

A study of the 99Tc(p,d)98Tc reaction

The energy levels of ⁹⁸Tc were studied with the ⁹⁹Tc(p, d)⁹⁸Tc reaction at a bombarding energy of 22.9 MeV and 15 keV resolution (FWHM). The Q-value for this reaction was found to be ?6.755 ± 0.009 MeV and the ⁹⁸Tc mass excess was calculated to be ?86.421 ± 0.011 MeV. This reaction provided the excitation energies for 49 neutron hole states below 1.5 MeV excitation. Comparison of experimental angular distributions with DWBA calculations permitted assignment of lf-values and the extraction of spectroscopic factors for 44 of these levels. Extensive configuration mixing is observed except in the low-lying multiplet. Effective proton-particle, neutron-hole interaction matrix elements were obtained from the low-lying positive-parity multiplet of ⁹⁸Tc.     

Production scheme for diagnostic-therapeutic radioisotopes by accelerator neutrons

Interest has been growing in the development of medical radioisotopes used for noninvasive nuclear medicine imaging of disease and cancer therapy. Especially the development of an alternative production scheme of ⁹⁹Mo, the mother radioisotope of ^99mTc used for imaging, is required, because the current supply chain of the reactor product ⁹⁹Mo is fragile worldwide. We have proposed a new production scheme of ⁹⁹Mo as well as therapeutic radioisotopes, such as ⁶⁴Cu and ⁶⁷Cu, using accelerator neutrons provided by the ^natC(d,n) reaction. Based on this scheme we have obtained high-quality ^99mTc, ⁶⁴Cu, and ⁶⁷Cu suitable for clinical use by developing both production and separation methods of the radioisotopes. We proposed a new facility to constantly and reliably produce a wide variety of high-quality, carrier-free radioisotopes, including ⁹⁹Mo, with accelerator neutrons. We report on the development of the proposed scheme and future prospects of the facility toward the domestic production of medical radioisotopes.     

Determination of the Products of Irradiation of Natural Molybenum By Deuterons with Energy up to 13 MeV by Means of Semiconductor Gamma- and X-Ray Spectrometry

Introduction

Among the products of irradiation of natural molýbdenum by deuterons with energies up to 13 MeV, by means γ and X-ray speclrometry were identified these radlonudldes: ⁹⁹Nb, ^92mNb, ^95m+gNb ⁹⁶Nb, ⁹⁹Mo, ¹⁰¹Mo, ⁹²Tc, ^93m+gTc, ^94m+g^>Tc, ^95m+gTc, ⁹⁶Tc, ^97mTc, ^99mTc,¹⁰¹Tc, and ⁸⁹Zr. With the more intensive lines of γ transitions of ⁹⁰Nb, ⁹⁶Nb, ^93m+gTc, ^94m+gTc, ^95m+gTc, ⁹⁹Tc and ^97mTc accurate photon energies have been established and for the lines 1475.7 and 1520.5 keV of ⁹³Tc, 820.2 keV of ^95mTc, and 96.4 keV of ^97mTc also the absolute intensities of the emitted γ were determined. By means of aluminium foils, by which the set of Mo foils had been interlaid, the atomic recoil in forward and backward direction ivas established for the 17.82 mg/cm² Mo foils and deuteron energy up to 12.7 MeV and the ion current of 3.4 μA.     

Feasibility studies towards future self-sufficient supply of the 99Mo-99mTc isotopes with Japanese accelerators

In order to establish a self-sufficient supply of ^99mTc, we studied feasibilities to produce its parent nucleus, ⁹⁹Mo, using Japanese accelerators. The daughter nucleus, ^99mTc, is indispensable for medical diagnosis. ⁹⁹Mo has so far been imported from abroad, which is separated from fission products generated in nuclear reactors using enriched ²³⁵U fuel. We investigated ^99mTc production possibilities based on the following three scenarios: (1) ⁹⁹Mo production by the (n, 2n) reaction by spallation neutrons at the J-PARC injector, LINAC; (2) ⁹⁹Mo production by the (p, pn) reaction at E_p = 50–80 MeV proton at the RCNP cyclotron; (3) ^99mTc direct production with a 20 MeV proton beam from the PET cyclotron. Among these three scenarios, scenario (1) is for a scheme on a global scale, scenario (2) works in a local area, and both cases take a long time for negotiations. Scenario (3) is attractive because we can use nearly 50 PET cyclotrons in Japan for ^99mTc production. We here consider both the advantages and disadvantages among the three scenarios by taking account of the Japanese accelerator situation.     

Radionuclide Purity of Deliveries of 99mTc Sodium Pertechnate from the Extraction Generator of the Institute of Nuclear Research, Řež, Compared with Imported Products

A method is presented of a random control of the radionuclide purity of deliveries of ^99mTc sodium pertechnate pro inj. from the extraction generator of the Institute of Nuclear Research in ?e?. Results are shown of measuring values of activities (in percentage) of the contaminants ⁹⁹Mo, ¹³¹I, ⁶⁹Co and ¹⁸⁸Re from 1983 to 1986 and after adjusting the technology of the production in 1987. Values of the activity in percentage of the contaminants of deliveries of ^99mTc solutions from the generator ⁹⁹Mo-^99mTc of the Institute of Nuclear Research with ⁹⁹Mo separated from fission products at the Institute of Nuclear Research in ?e? and that separated from fission products in the Zentralinstitut für Kernforschung — Dresden are compared with values of the activity (in percentage) of contaminants of eluates from radionuclide clution generators ⁹⁹Mo-^99mTc AMERTEC II. Elution generators were made in the Zentralinstitut für Kernforschung — Dresden and elution generator MTc-G-3 from the Isotope Production and Reactor Centre Swierk — Poland.     

Interaction Products of 12·5 Deuterons with Molybdenum and their Isolation Possibilities from Worn-out Cyclotron Parts

Using chemical separations and radiometric measurements medium-half-life irradiation products of molybdenum with 12.5 MeV deuterons were determined (⁹⁰Nb, ⁹²Nb, ^95mNb, ⁹⁵Nb, ⁹⁶Nb, ⁹⁹Mo, ^95mTc, ⁹⁶Tc, ^99mTc) as well as thick target yields for some of them: ⁹²Nb (0.22 μCi/μAh), ⁹⁵Nb(0.05 μCi/μAh), ⁹⁹Mo (64 μCi/μAh), ^95mTc(0.76 μCi/μAh), ⁹⁶Tc((62.5 μCi/μAh). Moreover isolation possibiities of radioactive preparations from removed worn-cut molybdenum parts of the U-120 cycletron are discussed.     

Zur 99m Tc-Markierung von Serumalbumin

Die günstigen Eigenschaften des Radionuklides ^99m Tc und die Mögliehkeit, ^99m Tc bei Bedarf von einem ⁹⁹Mo enthaltenden Generator abzumelken, haben zu einem breiten Anwendungsspektrum des Technetiums in der Xiiklcarincdizin geführt.     

Theg-factor of the 181 keV level of99Tc and hyperfine fields of Tc in Fe,Co, Ni

Theg-factor of the 181 keV-level of⁹⁹Tc has been redetermined by the spin rotation method. Measurements with polycrystalline sources of Tc in Fe, Co, and Ni yielded values of the hyperfine fields at the Tc nucleus. $$\begin{gathered} g = + 1.310(25) \hfill \\ H_{hf} (Tc{\mathbf{ }}in{\mathbf{ }}Fe) = ( - )290(15)kOe \hfill \\ H_{hf} (Tc{\mathbf{ }}in{\mathbf{ }}Co) = ( - )170(5)kOe \hfill \\ H_{hf} (Tc{\mathbf{ }}in{\mathbf{ }}Ni) = - 47.8(1.5)kOe. \hfill \\ \end{gathered} $$      

Zur Zerfallskonstanten der inneren Konversion von 99mTc im metallischen Zustand

In der Skala der Zerfallskonstanten für die innere Konversion von ^99mTc weisen gerade die Meβwerte für die metallischen Proben eine ungewöhnlich groβe Streuung auf. Einige Messungen enthüllen einen Zusammenhang zwischen dieser Streuung und einigen Probenparametern (Schichtdieke, Homogenitāt, Grad der durchgeführten Reduktion). Auf der Grundlage eines theoretischen Streuwellenbildes für die chemischen Effekte auf die innere Konversion von ^99m Tc wird nun verstāndlich, daβ alle Unzulānglichkeiten bei der Probenprāparation den Meβwert in eine Richtung verschieben. So wird mit Hilfe der Messung der Zerfallskonstanten der inneren Konversion von ^99mTc eine Bewertung der Güle dünner metallischer Technetiumschichten möglich.

In the pattern of decay constants for the internal conversion of ^99mTc, just the measured values of metallic samples are subject to unusually high scattering. Own measurements reveal an interdependence between this scattering and some sample parameters (thickness of layers, homogeneity, degree of conducted reduction). On the basis of a theoretical scattered wave pattern for the chemical effects on the internal conversion of ^99mTc it is becoming clear, that any deficiencies in sample preparation shift the measured values towards some direction. So, measurement of decay constants of the internal conversion of ^99mTc renders possible an estimation of the quality of thin metallic technetium layers.     

Ruthenium Radioisotopes as Contaminants in Eluates from 99Mo-99mTc Generators

The measurement of the ¹⁰⁶Ru content in ^99mTc eluates from ⁹⁹Mo-^99mTc generators is difficult because of the proximity of the ¹⁰³Ru and ¹⁰⁶Ru gamma-ray spectral peaks and the low ¹⁰⁶Ru content. ¹⁰⁶Ru causes a relatively high whole-body dose, similarly as known contaminants ⁶⁰Co, ¹³⁴Cs, ¹⁴⁰Ba and some others. Assuming that ruthenium is eliminated from the body with the biological half-life 7.3 days (according to ICRP) the additional absorbed dose caused by ¹⁰⁶Ru does not exceed, with regard to the low content of this nuclide, the dose due to ¹⁰³Ru. The results are given of the preliminary experiment in animals with the aim to determine the biological behaviour of ruthenium radioisotopes after the administration of the ^99mTc eluate containing these contaminants.     

Experimental plant for investigation of the possibility of linac-based production of medicine-intended isotopes

We describe a technique of obtaining radioactive ^99mTc isotope by irradiation of molybdenum with high-intensity beam of bremsstrahlung photons from the electron beam of the linear electron accelerator (LUE50) of the Alikhanyan National Science Laboratory (ANSL, former Yerevan Physics Institute). We have elaborated and created an experimental plant for development of ^99mTc production technology. Upgrading of linac has been performed aimed at raising the beam intensity and density. A system of automated control of the parameters of the plant and accelerator was built up. We carried out preliminary studies of ^99mTc obtaining technique and give quantitative and qualitative results.     

Study of the Elution Profile of the 99mTc Gel Generator

The generator with gel matrix is considered a perspective type for obtaining ^99mTc. The elution yield of a generator and the course of the elution profile A_Vn = f(V_n) are affected by the properties and conditions of preparation of zirconium molybdate (generator matrix). Furthermore, it is influended by neutron flux density as well as irradiation time and temperature of cooling water during the irradiation. Zirconium molybdate, Mo: Zr = 1.72, in the form of a monodispersion (mean particle size x = 0.175 mm), was irradiated under the neutron flux density ?_n = (0.7 … 2.2) × 10¹³ cm^?2 s^?1. The elution profile and the elution yield of ^99mTc were examined in dependence on the temperature of drying the Zr–Mo matrix (40–100 °C). The kinetics of the passage of ^99mTc into the solution, in dependence on the temperature of drying the hydrogel, was investigated. Some predetermined substitutional functions were tested and the mechanism of the ^99mTc passage into solution was explained.     

Acid effect on 99mTc and 99Mo mutual separation and their transport across supported liquid membrane extraction system

Work on ^99mTc extraction using supported liquid membrane (SLM) has been performed with tri-n-octylamine as a carrier. MoO ₄ ^2- ions transport with TOA-xylene has alos been studied with respect to HCl concentration (0.001 to 0.05M) in the feed solution. ^99mTc transport in the same HCl concentration range has shown that while MoO ₄ ^2- ions flux is higher at <0.01M HCl, in the order of (15–20)×10^–5mol/m².s, the TcO ₄ ^- ions flux is in the range of (5–7)×10^–11 mol/m².s. In case of sulphuric acid in the feed the transport of ^99mTc has been found to be higher ((28–55)×10^–11 mol/m²), while ⁹⁹Mo transport is observed to be suppressed as the H₂SO₄ concentration in the feed solution increases, providing a useful method for extraction of ^99mTc, produced from the disintegration of ⁹⁹Mo with time. Membranes supports used are of polypropylene and PTFE material. Effect of acid on Mo species present in the feed solution and the mechanism of transport through the SLM are also discussed.     

Measurements of magnetic moments of Tc isotopes and the hyperfine field of Tc in Fe and Ni

We report measurements of nuclear magnetic resonance on oriented nuclei (NMR-ON) on⁹⁴Tc (I=7⁺,T _1/2=4.9 h),⁹⁵Tc (I =9/2⁺,T _1/2=20 h) and⁹⁶Tc (I =7⁺,T _1/2=4.3 d) in Fe and on⁹⁵Tc and⁹⁶Tc in Ni. In order to elucidate the discrepancies on the hyperfine field of TcFe in the literature, the resonances were measured with high precision as a function of the external magnetic field B_ext up to 2.0 T. In addition, TDPAC measurements were performed on⁹⁹TcFe at T=300 K and 13 K. TheT=0 K hyperfine fields of Tc in Fe and Ni were determined to be –314(3) kG and –51.8(5) kG, respectively. The g-factors of⁹³Tc,⁹⁴Tc,⁹⁵Tc,⁹⁶Tc and⁹⁹Tc(E=181 keV;I =5/2⁺) are redetermined as g(⁹³Tc)=1.405(14), g(⁹⁴Tc)=0.731(7),g(⁹⁵Tc)=1.321(13), g(⁹⁶Tc)=0.727(7), g(⁹⁹Tc)=1.390(17).We wish to thank E. Smolic and G. Seewald for experimental help. This work was funded by the German Federal Minister for Research and Technology (BMFT) under the contract number 06TM353/TP 4, by the Deutsche Forschungsgemeinschaft (DFG) under the contract numbers Ha 1282/3-1,2, and, partly, by the Kernforschungszentrum, Karlsruhe.     

The decay of 18.2m 104Tc

¹⁰⁴Tc was produced through the¹⁰⁴Ru(n, p)¹⁰⁴Tc reaction using target material enriched to 99.7% in¹⁰⁴Ru. The energies and intensities of theγ-rays emitted by¹⁰⁴Tc were measured with a multichannel Ge(Li) spectrometer. A revised level scheme is proposed which contains 33 levels and incorporates 85γ- ray transitions. The half life of¹⁰⁴Tc was observed to be 18.2±0.5 min.     

High-spin structures of the odd-A 43 97−105 Tc isotopes

The ^99?105Tc isotopes have been produced at high spin as fission fragments following the fusion reaction ³⁷Cl(170 MeV) + ¹⁷⁶Yb and studied with the Euroball3 array. The high-spin structures of ¹⁰³Tc have been identified for the first time. From the systematics of the yrast states of ^97?105Tc, the location of individual proton states can be analyzed as a function of the neutron number.