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This study investigated the feasibility of a simplified method of alpha spectroscopy for radionuclidic purity tests at 225Ac production sites that eliminates the need for a vacuum chamber. The impact of enhancing the energy resolution using a collimator was evaluated through radiation transport simulations. The results showed that a full width at tenth maximum (FWTM) of <300 keV was achieved for alpha particles from 241Am, for which the main energy peak was 5.5 MeV. Experimental validation using an electrodeposition source containing 237Np, 241Am, and 244Cm confirmed an FWTM of 272 keV for both 241Am and 244Cm. These two peaks, with a difference of ~300 keV, were effectively separated. In response to the growing demand for targeted radioisotope therapy, this simplified alpha spectroscopy method offers the potential to detect 226Ra mixed with 225Ac generated by accelerators, given the alpha energy difference of ~700 keV. [ABSTRACT FROM AUTHOR]

A labeling technique was developed for the imidazoline I2 receptor ligand 2‐(3‐fluoro‐tolyl)‐4, 5‐dihydro‐1H‐imidazole (FTIMD) using Pd(0)‐mediated 11C‐carbomethoxylation with [11C]CO, followed by imidazoline ring formation with ethylenediamine‐trimethylaluminium (EDA‐AlMe3). To achieve this, [11C]CO was passed through a methanol (MeOH) solution containing 3‐fluoro‐4‐methylphenylboronic acid (1), palladium (II) acetate (Pd [OAc]2), triphenylphosphine (PPh3), and p‐benzoquinone (PBQ). The mixture was then heated at 65°C for 5 min. EDA was introduced into the reaction mixture, and MeOH was completely evaporated at temperatures exceeding 100°C. The dried reaction mixture was combined with an EDA‐AlMe (1:1) toluene solution and heated at 145°C for 10 min. Portions of the reaction mixture were analyzed through high‐performance liquid chromatography, resulting in [11C]FTIMD with 26% (n = 2) decay‐corrected radiochemical yield (RCY). This method could be utilized for various arylborons to produce [2‐11C]imidazolines 4a–h with RCYs ranging from low to moderate. Notably, [2‐11C]benazoline was obtained with a moderate RCY of 65%. The proposed technique serves as an alternative to the Grignard method, which uses [11C]CO to generate a [2‐11C]‐labeled imidazoline ring. [ABSTRACT FROM AUTHOR]

Rhodium-103m is one of the most attractive Auger electron emitters for internal radiotherapy. The half-life of 103mRh is relatively short (56.114 min). Therefore, it needs to be produced using a generator for clinical use. Most studies of 103Pd/103mRh generators using anion-exchange resins were carried out over 50 years ago. However, these resins are no longer commercially available. In the present study, we tested a 103Pd/103mRh generator using alternative anion-exchange resins (i.e., IRA904, IRA410, SA20A, and SA11AL). No-carrier-added 103Pd was used to make the generators. The 103mRh product was eluted from the generators using 6 mL of 0.1 M HCl with a flow rate 0.5 mL/min. The generator made from SA11AL showed good performance, with a yield of 39 %, an impurity level of 103Pd in the product of 0.29 %, and an operation time of 14 min. This makes this generator competitive with previously developed ones. [ABSTRACT FROM AUTHOR]

Auger electrons can cause nanoscale physiochemical damage to specific DNA sites that play a key role in cancer cell survival. Radio-Pt is a promising Auger-electron source for damaging DNA efficiently because of its ability to bind to DNA. Considering that the cancer genome is maintained under abnormal gene amplification and expression, here, we developed a novel 191Pt-labeled agent based on pyrrole–imidazole polyamide (PIP), targeting the oncogene MYCN amplified in human neuroblastoma, and investigated its targeting ability and damaging effects. A conjugate of MYCN-targeting PIP and Cys-(Arg)3-coumarin was labeled with 191Pt via Cys (191Pt-MYCN-PIP) with a radiochemical purity of >99%. The binding potential of 191Pt-MYCN-PIP was evaluated via the gel electrophoretic mobility shift assay, suggesting that the radioagent bound to the DNA including the target sequence of the MYCN gene. In vitro assays using human neuroblastoma cells showed that 191Pt-MYCN-PIP bound to DNA efficiently and caused DNA damage, decreasing MYCN gene expression and MYCN signals in in situ hybridization analysis, as well as cell viability, especially in MYCN-amplified Kelly cells. 191Pt-MYCN-PIP also induced a substantial increase in cytosolic dsDNA granules and generated proinflammatory cytokines, IFN-α/β, in Kelly cells. Tumor uptake of intravenously injected 191Pt-MYCN-PIP was low and its delivery to tumors should be improved for therapeutic application. The present results provided a potential strategy, targeting the key oncogenes for cancer survival for Auger electron therapy. [ABSTRACT FROM AUTHOR]

The excitation function of the natCu(3He,x)65Zn nuclear reaction was measured from its threshold up to 53 MeV incident energy relative to the natTi(3He,x)48V monitor reaction by using the conventional stacked foil activation technique combined with HPGe γ-ray spectrometry. Our result is systematically higher than the IAEA recommendation, and more experimental works are desired especially above 25 MeV.