Search

The implementation of the Variable Energy (VE) feature in the previously fixed-energy IBA Cyclone® Kiube cyclotron is presented as an upgrade enabling the production of novel radioisotopes with improved radionuclidic purity and production yields. The possibility of easily decreasing the energy of the extracted proton beam, from 18 down to 13 MeV, allows us to avoid the use of degraders and/or thick target windows, thus preventing related beam current limitations. The immediate application of the Variable Energy feature is proven by presenting the improved results obtained for the production of 68Ga from the irradiation of liquid targets simultaneously in terms of radionuclidic purity and activity produced. [ABSTRACT FROM AUTHOR]

The present work promotes and validates the benefits of using niobium instead of Havar® as the material for the target windows in most routine irradiations in cyclotrons. Calculation of the material activation and measurements of the contamination of the transferred target liquids show major improvements with the use of niobium. Also, the data of the daily routine productions at our production center are presented, proving that Havar® is not mandatory unless large target currents and/or pressures are required. [ABSTRACT FROM AUTHOR]

On the verge of a theranostic approach to personalised medicine, copper-64 is one of the emerging radioisotopes in nuclear medicine due to its exploitable nuclear and biochemical characteristics. The increased demand for copper-64 for preclinical and clinical studies has prompted the development of production routes. This research aims to compare the (p,n) reaction on nickel-64 solid versus liquid targets and evaluate the effectiveness of [64Cu]CuCl2 solutions prepared by the two routes. As new treatments for neurotensin receptor-overexpressing tumours have developed, copper-64 was used to radiolabel Neurotensin (8-13) and Neuromedin N. High-quality [64Cu]CuCl2 solutions were prepared using ACSI TR-19 and IBA Cyclone Kiube cyclotrons. The radiochemical purity after post-irradiation processing reached 99% (LT) and 99.99% (ST), respectively. The irradiation of a solid target with 11.8 MeV protons and 150 μAh led to 704 ± 84 MBq/μA (17.6 ± 2.1 GBq/batch at EOB). At the end of the purification process (1 h, 90.90% activity yield), the solution for peptide radiolabelling had a radioactive concentration of 1340.4 ± 70.1 MBq/mL (n.d.c.). The irradiation of a liquid target with 16.9 MeV protons and 230 μAh resulted in 3.7 ± 0.2 GBq/batch at EOB, which corresponds to an experimental production yield of 6.89 GBq.cm3/(g.µA)sat. Benefiting from a shorter purification process (40 min), the activity yielded 90.87%, while the radioactive concentration of the radiolabelling solution was lower (492 MBq/mL, n.d.c.). The [64Cu]CuCl2 solutions were successfully used for the radiolabelling of DOTA-NT(8-13) and DOTA-NN neuropeptides, resulting in a high RCP (>99%) and high molar activity (27.2 and 26.4 GBq/μmol for LT route compared to 45 and 52 GBq/μmol for ST route, respectively). The strong interaction between the [64Cu]Cu-DOTA-NT(8-13) and the colon cancerous cell lines HT29 and HCT116 proved that the specificity for NTR had not been altered, as shown by the uptake and retention data. [ABSTRACT FROM AUTHOR]

The present work describes a method to determine excitation function curves and, therefore, cross-sections, making use of the irradiation of liquid targets at distinct energies in a biomedical cyclotron. The method relies on the derivative of experimentally measured thick target yield curves to determine the corresponding excitation function curves. The technique is presented as a valid and practical alternative to the commonly used activation method combined with the stack monitor technique, whose implementation in liquid targets offers practical difficulties. The working principle is exemplified by presenting the results obtained for the clinically relevant 68Zn(p,n)68Ga and the 64Zn(p,α)61Cu nuclear reactions, obtained though the irradiation of liquid targets containing dissolved natural zinc. [ABSTRACT FROM AUTHOR]

This work presents a simulation model developed with the aim to represent and study the thermal behavior of cyclotron liquid targets. Understanding and improving the thermal behavior of the target system is fundamental to improving the target overall performance, especially when using thick target windows, for which a larger amount of heat generated can be limiting. ANSYS CFX and SRIM software were used to develop a simulation model representing the IBA Nirta® Ga-68 liquid target system, to study the use of thick niobium target windows. The model was validated by comparing the results with experimental data obtained for the same liquid target system. In the present study, simulation results and temperature distributions of the main target components were obtained by studying the main parameters of interests, such as the initial temperature and mass flow rate of the coolants, and also distinct target windows with different thicknesses. [ABSTRACT FROM AUTHOR]

A new technique is presented for high-pressure gaseous radiation detectors leading to pulse amplitudes at least one order of magnitude larger than in ionization-chamber-based gamma-ray detectors. The technique uses room-temperature pure Xe or Xe-based gaseous mixtures at pressures of about 5–20 bar (or higher) to detect ionizing radiation in a multigrid high-pressure gas proportional scintillation counter (MGHP-GPSC) with a CsI deposit as the photocathode in direct contact with the gas, with no optical windows. The detector relies on secondary scintillation as the amplification stage followed by photoelectron production in a CsI photocathode layer. Experimental results are presented for a small prototype filled with pure Xe up to 5 bar, showing that the principle of operation of the detector works. The maximum detector gain obtained so far is about 10. [ABSTRACT FROM PUBLISHER]

An experimental study of the ω-values and Fano factors for Ar-Xe gaseous mixtures at atmospheric pressures for 5.895 keV X-rays was carried out with two experimental set-ups based on gas proportional scintillation counter techniques. For the 100% Xe, Ar-40% Xe, Ar-20% Xe and Ar-10% Xe mixtures at 800 Torr the measured ω-values were 21.61 eV, 21.63 eV, 21.64 eV and 21.42 eV, respectively, within an accuracy of ±0.21 eV. For the same mixtures the Fano factors were 0.254, 0.258, 0.250 and 0.256, respectively, within an accuracy of about ±0.004. For lower Xe concentrations of 5%, 3% and 1% the Fano factors were ≈0.24, ≈0.23 and ≈0.22, respectively. These experimental results are compared with those available in the literature. [ABSTRACT FROM AUTHOR]