A novel trigonal conjugate of glutathiones with a 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene core was synthesized and its self-assembling behavior was investigated in water. Three glutathione units were regulated to orient on the same side of the benzene ring, through steric repulsions between ethyl groups attached on the benzene core. Concentration dependence of 1H NMR chemical shifts in D2O revealed formation of molecular assemblies with two affinity constants (Ka = 4.75 × 102 and 6.76 × 104 M−1), which reflect stepwise assembly directed by electrostatic interactions, hydrophobic interactions, and hydrogen bonding. In scanning electron microscopy, hard spherical assemblies with the size of 310 ± 50 nm were observed at high concentration (10 mM), whereas slightly disordered spherical assemblies were obtained at lower concentrations. The spherical assemblies self-assembled from the conformation-regulated trigonal glutathiones showed regular morphology and enhanced rigidity compared to those formed from conformationally non-regulated trigonal glutathiones.

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In recent years, a novel radiochromic gel dosimeter was developed that utilizes the color development of a polyvinyl alcohol-iodide (PVA-I) complex. In this study, we explore the effects of different iodide salts (LiI, NaI, KI, CsI, NH4I, CaI2, and ZnI2) and PVAs with different degrees of polymerization (500, 1000, and 1500) and saponification (80, 88, and 98 mol%) were investigated on a PVA-GTA-I gel dosimeter using PVA that was chemically crosslinked with glutaraldehyde (GTA) as a matrix. The results showed that these substitutions had negligible effect on dose-responses, such as sensitivity and dose-rate independence.

Medical linear-accelerator-based stereotactic radiosurgery (SRS) using a stereotactic apparatus or image-guided radiotherapy system for intracranial lesions is performed widely in clinical practice. In general, Winston–Lutz (WL) tests using films or electric portal imaging devices (EPIDs) have been performed as pre-treatment and routine quality assurance (QA) for the abovementioned treatment. Two-dimensional displacements between the radiation isocentre and mechanical isocentre are analysed from the test; therefore, it is difficult to identify the three-dimensional (3D) isocentre position intuitively. In this study, we developed an innovative 3D WL test for SRS-QA using a novel radiochromic gel dosimeter based on a polyvinyl alcohol-iodide (PVA-I) complex that can be reused after annealing. A WL gel phantom that was consisted of the PVA-I gel dosimeter poured into a tall acrylic container and an embedded small tungsten sphere was used as a position detector. A flatbed scanner was used to analyse the isocentre position. The measured 3D isocentre accuracy from the gel-based WL test was within 0.1 mm compared with that obtained from the EPID-based WL test. Furthermore, excellent reusability of the WL gel phantom was observed in long-term SRS isocentre verification, in which clinical SRS cases involving repeated irradiation and annealing were analysed. These results demonstrate the high accuracy and reliable evaluation of the isocentre position using an innovative test. In addition, the clinical-based routine SRS-QA using the PVA-I gel dosimeter demonstrates a highly convenience while affording an easy and fast analysis process.

A novel radiochromic gel dosimeter based on a poly(vinyl alcohol)-iodide complex (PVA-I) has been developed with the aim of using it in optical computed tomography (CT). The PVA-I gel dosimeter exhibits excellent characteristics such as high sensitivity, dose rate independence, a wide dose range, and especially reusability. The standard PVA-I gel dosimeter is composed of poly(vinyl alcohol) (average degree of polymerization 1000 and degree of saponification 88 mol%), iodide (potassium iodide), reducing sugar (fructose), gelling agent (gellan gum), and water. In this study, the influence on dose response is investigated upon substitution of the components by PVAs with different degrees of polymerization (500, 1500, 3500) and saponification (80 mol%, 98 mol%), different iodide salts (LiI, NaI, NH4I), and different reducing sugars (glucose, maltose, lactose). The results show that these substitutions have little effect on the dose rate dependence, while the iodide salt affects the sensitivity.

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The aim of our study is to evaluate whether an 18 F-FDG PET/CT image quality is influenced by the obesity type visceral fat or subcutaneous fat. Methods: We chose continuously 68 patients with obesity (35 subcutaneous fats and 33 visceral fats) who underwent an 18 F-FDG PET/CT scan at our clinic from January 3, 2015 to June 30, 2015. And then, we calculated the noise equivalent count (NECdensity), the signal to noise ratio of the liver (SNRliver), and the ratio of random coincidence counts to total prompt (random/prompt countrate) on each PET/CT image. Results: We observed that NECdensity was decreased as the body mass index (BMI) and the abdominal circumference increased regardless of the obesity type. When the BMI was on the same degree between two types, however, NECdensity of a visceral fat was 21.6% that is inferior to that of subcutaneous fat on the average. A similar relation was satisfied also in abdominal circumference. Conversely, random/prompt countrate of a visceral fat was more than that of subcutaneous fat when the abdominal circumference and BMI were on the same degree, respectively. Overall, random/prompt countrate tended to increase as BMI and the abdominal circumference increased. With respect to SNRliver , the value of a visceral fat was inferior to that of subcutaneous fat unconditionally. Conclusion: When the BMI and abdominal circumference are on the same degree, respectively, the 18 F-FDG PET/CT image quality of visceral fat is inferior to that of subcutaneous fat. The measure is to extend the collection time by about 20% in the pelvic area from the abdomen of visceral fat type obesity.