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Pancreatic cancer remains difficult to diagnose using currently available imaging probes. Thus, this study aimed to develop a novel imaging agent for the diagnosis of pancreatic cancer using positron emission tomography (PET). Specifically, this study explores gelatin-based nanoparticles fabricated via radiation-induced crosslinking, as gelatin is known for its ability to produce biocompatible materials. Aqueous gelatin solutions were irradiated with γ-rays to produce nanoparticles with average diameters of 5–20 nm via a radiation crosslinking technique. The gelatin nanoparticles were labeled with 64Cu, exhibiting negative surface potentials. Furthermore, the nanoparticles were evaluated in vivo by injecting them into pancreatic tumor-bearing mice. Notably, the nanoparticles accumulated in the tumors. Hence, 64Cu-labeled gelatin nanoparticles show promise as a platform for next-generation PET imaging agents for pancreatic cancer. [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]

Four novel diamide and triamide extractants developed in our group, TODGA, DOODA, MIDOA, and NTAamide, were examined to see the extractability trends of up to 74 metal ions from nitric acid inton-dodecane. TODGA and DOODA have one or two etheric and two amidic oxygen donor atoms, and MIDOA and NTAamide have a nitrogen donor atom centered in the backbones and two or three diamidic O atoms. The former two extractants are expected to have high extractability for metal ions classified as hard acids and the latter ones have higher extractability for soft acids. TODGA and DOODA have high distribution ratios,D, for metal ions in the 2A-4A groups. On the other hand, MIDOA and NTAamide have highDvalues for group 5A-7A and 8 metal ions, which follows HSAB theory. The positive relation between the slope values of the extractant dependence and the extraction constant, α, is found, which suggests that a high order of successive formation of metal complexes with extractants gives high extractability. [ABSTRACT FROM PUBLISHER]

Abstract: Introduction: 3-[18F]fluoro-α-methyl-l-tyrosine ([18F]FAMT) is a useful amino acid tracer for positron emission tomography (PET) imaging of malignant tumors. FAMT analogs labeled with 76Br, a positron emitter with a long half-life (t 1/2=16.1 h), could potentially be widely used as amino acid tracers for tumor imaging. In this study, 3-[76Br]bromo-α-methyl-l-tyrosine ([76Br]BAMT) was designed, and its usefulness was evaluated as a novel PET tracer for imaging malignant tumors. Methods: In this study, both [76Br]BAMT and [77Br]BAMT were prepared. The in vitro and in vivo stability of [77Br]BAMT was evaluated by HPLC analysis. Cellular uptake and retention of [77Br]BAMT and [18F]FAMT were evaluated using LS180 colon adenocarcinoma cells. Biodistribution studies were performed in normal mice and in LS180 tumor-bearing mice, and the tumors were imaged with a small-animal PET scanner. Results: [77Br]BAMT was stable in vitro but was catabolized after administration in mice. Cellular accumulation and retention of [77Br]BAMT were significantly higher than those of [18F]FAMT. In biodistribution studies, the tumor accumulation of [77Br]BAMT was higher than that of [18F]FAMT. However, some level of debromination was seen, which caused more retention of radioactivity in the blood and organs than was seen with [18F]FAMT. PET imaging with [76Br]BAMT enabled clear visualization of the tumor, and the whole-body image using [76Br]BAMT was similar to that using [18F]FAMT. Conclusions: [77Br]BAMT showed high levels of tumor accumulation, and [76Br]BAMT enabled clear visualization of the tumor by PET imaging. Although an improvement in stability is still needed, 76Br-labeled FAMT analogs could potentially serve as PET tracers for the imaging of malignant tumors. [Copyright &y& Elsevier]