Speaker
Summary
Lead-212 (T1/2 = 10.6 h) and lead-203 (T1/2 = 51.9 h) can be used as a theranostic pair of isotopes for applications in nuclear medicine. 212Pb is used for α-targeted therapy, while its counterpart 203Pb is suitable for SPECT imaging thanks to its 279.2 keV (80.9%) γ-emission. Currently, 203Pb is produced by irradiating natural Tl, Tl-203 and Tl-205 targets, with protons. In this work, we investigate an alternative production route using 205Tl irradiated with deuterons at GIP Arronax [1] [2].
To prepare enriched Tl-205 targets, we employed an electrodeposition technique using pulse-reverse current onto a gold substrate. Deposition was carried out at 25°C and pH 8, using EDTA as a complexing agent, hydrazine to prevent oxidation, and Brig-35 as a surfactant. A uniform 40 µm deposit with good adhesion was obtained [3]. Separation of Tl and Pb was achieved using Triskem's Pb resin, yielding high-purity Pb-203 in 1 M ammonium acetate solution (pH 5).
Since September 2023, monthly production has been scaled up by increasing the beam intensity (from 50 µA to 70 µA) and irradiation time (from 1 h to 10 h). At Calibration Time (CT, 2 days post-EOB), the radionuclidic purity of Pb-203 exceeded 99.3%, with all impurities below the γ-spectrometry detection limit, except for Pb-201 (< 0.7%). Up to 15 GBq of Pb-203 was obtained at CT. Pb recovery averaged 81 ± 4%, while metallic impurities (Tl, Fe, Ni, Zn, Cu, Hg, and Au) remained below detection limits. Tl recovery consistently exceeded 90%, enabling recycling.
These results demonstrate the feasibility of large-scale production of high-purity Pb-203. Further technical details will be presented in the poster.
[1] F. Haddad et al., “ARRONAX, a high-energy and high-intensity cyclotron for nuclear medicine,” Eur J Nucl Med Mol Imaging, vol. 35, no. 7, pp. 1377–1387, 2008, doi: 10.1007/s00259-008-0802-5.
[2] T. Sounalet et al., “Production of 203Pb from enriched 205Tl using deuteron beams,” Appl Radiat Isot, p. 111190, 2024, doi: 10.1016/j.apradiso.2024.111190.
[3] T. Sounalet et al., “Manufacture of Tl targets by electrodeposition for the study of excitation functions of 203Pb,” EPJ Web Conf., vol. 285, p. 09001, 2023, doi: 10.1051/epjconf/202328509001.
| Are you interested/eligible for the Young Session? | No, I am not eligible |
|---|
