[en] Nuclear data are compiled for the ten known members of the A = 134 mass chain. This compilation is based on references received through August 1974. Eight drawings are included which present most of the experimental data, including adopted values. Following the drawings are adopted level-property summaries and listings of experimental data for each member of the A-chain. A discussion of the decay scheme of each nuclide is presented in the Data Sheet section. Substantial detail is provided for the low-lying level structure of ¹³⁴I, ¹³⁴Xe, and ¹³⁴Ba from β-decay studies and of ¹³⁴Cs from (n,γ) studies. Known levels in ¹³⁴Te rely on systematics for their establishment, while considerable uncertainty still exists in ¹³⁴Ce levels from β decay. Two isomers are suggested for ¹³⁴Sb and ¹³⁴Pr by their decay properties. (HI,xnγ) reactions have established five excited levels in ¹³⁴Nd. Nothing is known about excited levels in ¹³⁴La, primarily because of the small Q value for ¹³⁴Ce β decay. There is a lack of particle-transfer reaction studies throughout this A-chain. (U.S.)

[en] In view of the short half-life of ¹³⁴La, it has generally proven convenient to study the ¹³⁴La decay scheme by using as a source the ¹³⁴La in equilibrium with its ¹³⁴Ce parent. This procedure, together with the reported low Q-value for the ¹³⁴Ce decay and the reported absence of γ radiation in the ¹³⁴Ce decay, has led to the assignment of several low-energy (approx. less than 0.3 MeV) γ rays to the ¹³⁴La decay in the recent A = 134 mass-chain evaluation. However, in the present study we have been able to associate for the first time a number of γ-ray transitions, ranging in energy up to approximately 355 keV, with the ¹³⁴Ce decay. This result indicates that the previously reported values for the ¹³⁴Ce decay energy are incorrect and that the three low-energy (less than 0.3 MeV) γ rays reported in the ¹³⁴La decay in fact are associated with the decay of ¹³⁴Ce

No abstract available

[en] The decay of ¹³⁴Ce to doubly odd ¹³⁴La has been studied using Ge(Li) and Si(Li) photon detectors. Samples of the ¹³⁴Ce(75.9h)-¹³⁴La(6.67 min) have been produced by approximately 800 MeV proton bombardment of Pr foils in LAMPF, followed by chemical and mass separation. To increase the sensitivity (by up to a factor approximately 50) for detection of ¹³⁴Ce γ-rays in the presence of the interfering ¹³⁴La activity, the ¹³⁴Ce-¹³⁴La samples were loaded onto a HDEHP column and the ¹³⁴La eluted off continuously. Gamma-ray singles and γ-γ coincidence measurements were made using the ¹³⁴Ce activity remaining on the column as the source. Some 32 γ-rays, ranging in energy up to 355 keV, are observed to be associated with this decay. Approximately 30 of these have been fitted into a level scheme for ¹³⁴La with excited states at energies of 31, 54, 93, 136 or 148, 162, 187, 150 or 205, 252, 294 and 355 keV. Only limits can be set for the spin and parity values of each of these states. The observation of γ-rays with energies up to 355 keV indicates that the previously reported values of approximately 0.1 MeV for the ¹³⁴Ce electron-capture decay energy, inferred from the K-electron capture probability, are incorrect. (Auth.)

No abstract available

[en] We propose the use of the Auger electron and positron-emitting generator ¹³⁴Ce/¹³⁴La (half-lives 3.16 d and 6.45 min) for radionuclide therapy. It combines emission of high-energy beta particles with Auger electrons. The high-energy beta particles have similar energies as those emitted by ⁹⁰Y. Many cancer patients receiving radionuclide therapy have both bulk tumours, which are best treated with high-energy beta particles, and single spread cells or micrometastasis, which are preferably treated with low-energy electrons such as Auger and conversion electrons. Furthermore, the positron-emitting ¹³⁴La can be used to study kinetics and dosimetry using PET. Production and PET performance were investigated and theoretical dosimetry calculations were made. PET resolution, recovery and quantitative accuracy were slightly degraded for ¹³⁴La compared to ¹⁸F. ¹³⁴Ce/¹³⁴La absorbed doses to single cells were higher than absorbed doses from ⁹⁰Y and ¹¹¹In. Absorbed doses to spheres representing bulk tumours were almost as high as for ⁹⁰Y, and a factor 10 higher than for ¹¹¹In. Whole-body absorbed doses, based on kinetics of the somatostatin analogue octreotide, were higher for ¹³⁴Ce/¹³⁴La than for ⁹⁰Y because of the ¹³⁴La annihilation photons. This initial study of the therapeutic possibilities of ¹³⁴Ce/¹³⁴La is encouraging and justifies further investigations. (author)

[en] ¹³⁴La emits positrons, enabling its use in positron emission tomography (PET) imaging in the form of an in vivo generator with its parent, ¹³⁴Ce. Due to similar ionic radius and coordination geometries, the ¹³⁴Ce/¹³⁴La pair can be used as a surrogate for ²²⁵Ac or ²²⁷Th (non-PET isotopes) in the investigation of novel alpha-emitting radiotherapeutics. This talk will focus on using the unique LANL capability at the Isotope Production Facility (IPF) at Los Alamos Neutron Science Center (LANSCE) to develop a production method for ¹³⁴Ce (t_1/2 = 75.9 h, daughter ¹³⁴La t_1/2 = 6.67 m, 2.7 MeV β+). In addition, the approach to scale-up for bulk ¹³⁴Ce production will be discussed. This process involves separation of microscopic amounts of ¹³⁴Ce from macroscopic quantities (g) of lanthanum target material. Particular attention is focused on the Ce-La separation development that relies on 'in-house' production of a ¹³⁹Ce tracer (t_1/2 = 137.6 d, 165.9 keV γ) via the ¹⁴¹Pr(n,3n)¹³⁹Pr→¹³⁹Ce reaction using the secondary neutron flux near a stack of IPF production targets

[en] The results are presented of an investigation of the ¹³⁴Ba level scheme as observed in the decay of ¹³⁴La. The properties of nuclides in this mass region (50 less than Z, N less than 82) are of considerable current interest because of the information which they provide concerning the collective potential-energy surfaces and how these surfaces vary with both proton and neutron number

[en] The level scheme of even-even ¹³⁴Ba has been studied from the decay of the ¹³⁴Ce (75.9 h) → ¹³⁴La (6.67 min) chain. Samples of ¹³⁴Ce were produced by approx.800-MeV proton bombardment of Pr foils, followed by chemical and mass separation. γ-ray energy and intensity measurements were made using Ge(Li) and Si(Li) detectors. Identification of γ rays as belonging to the ¹³⁴La dacay was made in separate experiments using sources of ¹³⁴La milked from the parent ¹³⁴Ce activity. In this manner, approx.99 γ-ray transitions have been associated with the ¹³⁴La decay scheme. From these data and γ-γ coincidence measurements, a comprehensive level scheme is proposed for ¹³⁴Ba, consisting of approx.41 excited states. Further information on the energies of levels in ¹³⁴Ba was derived from a subsidiary series of γ-ray energy measurements using a source of ¹³⁴Cs. For the ¹³⁴La decay, logft values were obtained from relative x-ray, annihilation-quanta, and γ-ray intensities and using intensity-balance considerations for the individual levels in ¹³⁴Ba. A comparison is made of the ¹³⁴Ba data with the predictions of several recent theoretical calculations dealing with even-even nuclei in this mass region

[en] The use of positron emission tomography (PET) has so far been limited to a few nuclides with short half-lives such as ¹⁸F and ¹¹C. Certain applications require nuclides with longer half-lives, such as ⁷⁶Br and ⁵²Fe. In radionuclide therapy positron emitting analogues of therapeutic nuclides, such as ^110mIn, or daughter nuclides, such as ¹³⁴La, can enable the use of PET in radionuclide therapy dosimetry. A challenge associated with the use of these positron-emitting nuclides is that they emit gamma radiation in cascade with positrons, which complicates quantitative PET imaging. Other possible complications are the high energies of the emitted positrons, and the decay of ⁵²Fe to the short-lived positron emitter ^52mMn. Performance measurements were done to investigate the effects of these decay characteristics on the quantitative accuracy, spatial resolution, and other parameters of PET. The distribution of gamma radiation coincidences in PET data was studied and correction methods were implemented and evaluated. PET resolution degrades with 1-2 mm for the studied nuclides in comparison with ¹⁸F. The implemented sinogram tail fit and delayed coincidence sinogram based correction methods for cascade gamma coincidences lead to a quantitative accuracy similar as for ¹⁸F. Standard dead time corrections are not accurate for these nuclides. Noise equivalent count rates are considerably lower for ⁷⁶Br than for ¹⁸F at clinically relevant radioactivity concentrations. A method to correct ⁵²Fe patient data for the contribution of the decay daughter ^52mMn is discussed. The use of ^110mIn is evaluated in a patient study and compared to SPECT imaging with ¹¹¹In. A dosimetric and PET evaluation of the of use ¹³⁴Ce/¹³⁴La for radionuclide therapy and dosimetry is presented. Dosimetry of ⁷⁶Br-labelled antibodies is evaluated in an animal study. Finally, the possibility to use PET for dosimetry during radionuclide therapy is studied and a dose image calculation program, based on PET measurements, is presented