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44 Sc is a β + -emitter which has been extensively studied for nuclear medicine applications. Its promising decay characteristics [t 1/2 = 3.97 h, E [Formula: see text] = 632 keV (94.3%), E γ = 1157 keV (99.9%); 1499 keV (0.91%)] make it highly attractive for clinical PET imaging, offering an alternative to the widely used 68 Ga [t 1/2 = 67.7 min, E [Formula: see text] = 836 keV (87.7%)]. Notably, its nearly fourfold longer half-life opens avenues for applications with biomolecules having extended biological half-lives and enables the centralized distribution of 44 Sc radiopharmaceuticals. An additional advantage of employing 44 Sc as a diagnostic radioisotope lies in its counterpart, the β - -emitter 47 Sc, which is currently under investigation for targeted radiotherapy. Together, they form an ideal theranostic pair, providing a comprehensive solution for both diagnostic imaging and therapeutic applications in nuclear medicine. At the Bern medical cyclotron, a study to optimize the production of scandium radioisotopes is currently ongoing. In this context, proton irradiation of titanium targets has been investigated, exploiting the reactions 47 Ti(p,α) 44 Sc and 50 Ti(p,α) 47 Sc. This approach enables the production of Sc radioisotopes within a single PET medical cyclotron facility, employing identical chemical procedures for target preparation and post-irradiation processing. In this paper, we report on cross-section measurements of the 47 Ti(p,α) 44 Sc nuclear reaction using 95.7% enriched 47 TiO 2 targets. On the basis of the obtained results, the production yield and purity were calculated to assess the optimal irradiation conditions. Production tests were performed to confirm these findings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

155 Tb is one of the most interesting radionuclides for theranostic applications. It is suitable for SPECT imaging and it can be used as a true diagnostic partner of the therapeutic 149 Tb and 161 Tb. Its production by proton irradiation using enriched 155 Gd and 156 Gd oxide targets is currently being investigated and represents a promising solution. To achieve the level of radionuclidic purity required in the clinical setting, the co-production of Tb impurities has to be minimized. For this purpose, an accurate knowledge of the cross sections of the nuclear reactions involved is of paramount importance. In this paper, we report on the assessment of cross sections of the reactions 154 Gd(p,xn) 153,154,154m1,154m2 Tb, 155 Gd(p,xn) 154,154m1,154m2,155 Tb, 156 Gd(p,xn) 155,156 Tb and 157 Gd(p,2n) 156 Tb derived with a specific data analysis procedure developed by our group. This method allows to disentangle the nuclear contributions from the production cross section by inverting linear systems of equations and it requires the measurement of the cross sections from as many materials as the reactions involved in the production of the radionuclide under study. For this purpose, the experimental data previously measured by our group at the Bern medical cyclotron by irradiating natural Gd 2 O 3 , enriched 155 Gd 2 O 3 and enriched 156 Gd 2 O 3 targets were used. For some of these nuclear reactions, cross sections were assessed for the first time. On the basis of our findings, production yield and purity can be calculated for any kind of isotopic composition of the enriched material., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Saverio Braccini reports financial support was provided by Swiss National Science Foundation., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

165 Er is a pure Auger-electron emitter with promising characteristics for therapeutic applications in nuclear medicine. The short penetration path and high Linear Energy Transfer (LET) of the emitted Auger electrons make 165 Er particularly suitable for treating small tumor metastases. Several production methods based on the irradiation with charged particles of Er and Ho targets can be found in the literature. In this paper, we report on the study of 165 Er indirect production performed via the 166 Er(p,2n) 165 Tm → 165 Er reaction at the 18 MeV Bern medical cyclotron. Despite the use of highly enriched 166 Er 2 O 3 targets, several Tm radioisotopes are produced during the irradiation, making the knowledge of the cross sections involved crucial. For this reason, a precise investigation of the cross sections of the relevant nuclear reactions in the energy range of interest was performed by irradiating Er 2 O 3 targets with different isotopic enrichment levels and using a method based on the inversion of a linear system of equations. For the reactions 164 Er(p, γ) 165 Tm, 166 Er(p,n) 166 Tm, 166 Er(p, γ) 167 Tm, 167 Er(p,3n) 165 Tm, 167 Er(p, γ) 168 Tm, 168 Er(p,2n) 167 Tm and 170 Er(p,3n) 168 Tm, the nuclear cross section was measured for the first time. From the results obtained, the production yield and purity of the parent radioisotope 165 Tm were calculated to assess the optimal irradiation conditions. Several production tests with solid targets were performed to confirm these findings., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Saverio Braccini, Zeynep Talip, Nicholas P. van der Meulen reports financial support was provided by Swiss National Science Foundation., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

RadioNuclide Therapy (RNT) in nuclear medicine is a cancer treatment based on the administration of radioactive substances that specifically target cancer cells in the patient. These radiopharmaceuticals consist of tumor-targeting vectors labeled with β - , α, or Auger electron-emitting radionuclides. In this framework, 67 Cu is receiving increasing interest as it provides β - -particles accompanied by low-energy γ radiation. The latter allows to perform Single Photon Emission Tomography (SPECT) imaging for detecting the radiotracer distribution for an optimized treatment plan and follow-up. Furthermore, 67 Cu could be used as therapeutic partner of the β + -emitters 61 Cu and 64 Cu, both currently under study for Positron Emission Tomography (PET) imaging, paving the way to the concept of theranostics. The major barrier to a wider use of 67 Cu-based radiopharmaceutical is its lack of availability in quantities and qualities suitable for clinical applications. A possible but challenging solution is the proton irradiation of enriched 70 Zn targets, using medical cyclotrons equipped with a solid target station. This route was investigated at the Bern medical cyclotron, where an 18 MeV cyclotron is in operation together with a solid target station and a 6-m-long beam transfer line. The cross section of the involved nuclear reactions were accurately measured to optimize the production yield and the radionuclidic purity. Several production tests were performed to confirm the obtained results., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Saverio Braccini reports financial support was provided by Swiss National Science Foundation., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)