Copenhagen Rats Display Dominantly Inherited Yet Non-uniform Resistance to Spontaneous, Radiation-induced, and Chemically-induced Mammary Carcinogenesis.

Background/Aim: Genetic and environmental factors interact to dictate the risk of cancer, and animal models are expected to provide avenues for identifying such interactions. The aim of the study was to clarify the genetic susceptibility of Copenhagen rats to spontaneous, radiation-induced, and chemically-induced mammary carcinogenesis. Materials and Methods: Female Copenhagen and Sprague– Dawley rats and their F1 hybrids were subjected at age 7 weeks to γ-irradiation or intraperitoneal injection with 1-methyl-1-nitrosourea or were not treated, and palpable mammary tumours were diagnosed histologically. Data were pooled with previous data acquired for both nontreated and irradiated Sprague–Dawley rats. Results: Radiation and 1-methyl-1-nitrosourea both significantly increased the incidence of mammary cancer in all strains. Copenhagen and F1 rats displayed a significantly lower incidence than Sprague–Dawley rats in all groups, with relatively higher incidence after irradiation. F1 rats exhibited significantly higher mammary cancer incidence than Copenhagen rats in the nontreated, but not the treated, groups. The interaction of the strain and exposure effects was suggested to be quasi-multiplicative. Conclusion: Copenhagen rats display non-uniform resistance to spontaneous, radiation-induced, and chemically-induced mammary carcinogenesis with dominant inheritance over Sprague–Dawley rats.journal articl

福島沖の動物プランクトンにおけるCs-137濃度の変動は群集構造や栄養段階構造から説明できるのか？

福島第一原子力発電所から大量の放射性核種が放出され，海洋に拡散された。事故後，水圏生物のCs濃度に関する研究は水産対象種を中心に多く行われているが，低次食段階生物に関しては群集構造や栄養段階を考慮していないものがほとんどである．福島原発沖の動物プランクトン中の137Cs濃度と動物プランクトンの個体数密度，群集構造や栄養段階構造の関係を明らかにすることを目的に動物プランクトンに含まれる137Cs濃度の測定を行なった。第23回「環境放射能」研究会conference objec

レーザー航跡場電子加速における光遷移放射イメージングの研究

We report on an experimental study of optical transition radiation (OTR) from high energy electron bunches generated by laser wakefield acceleration (LWFA) using the J-KAREN-P laser at Kansai Photon Science Institute (KPSI), QST. A three-color OTR imaging system was built to monitor the electron bunch duration variation in a single shot. By the insertion of a blade, relatively stable electron beams were generated using the density transition injection regime. Obvious OTR signal difference was observed between the conditions of pure gas and mixture gas. This experiment suggest that the combination of a sharp density down-ramp and pure gas is beneficial for generating stable and high-brightness electron bunches and the realization of a compact x-ray free electron laser.日本物理学会第77回年次大会conference objec

Long-term outcomes of high dose carbon-ion radiation therapy for unresectable upper cervical (C1-2) chordoma.

Background: Chordoma is a rare, locally invasive neoplasm of the axial skeleton. Complete resection is often difficult, especially for the upper-cervical (C1-2) spine. We evaluated the efficacy and safety of carbon-ion radiotherapy (CIRT) for unresectable C1-2 chordoma. Methods: Patients with C1-2 chordoma treated with definitive CIRT (60.8 Gy [RBE] in 16 fractions) were retrospectively analyzed. We evaluated OS, LC, PFS, and toxicity. Results: Nineteen eligible patients all completed the planned course of CIRT. With the median follow-up 68 months (range: 29-144), median OS was 126 months (range: 36-NA). Five-year OS, LC, and PFS were 68.4% (95% CI, 42.8%-84.4%), 75.2% (46.1%-90.0%), and 64.1% (36.3%-82.3%), respectively. Regarding acute toxicity of grade ≥3, there was only one grade 3 mucositis. Late toxicity included radiation-induced myelitis (grade 3 in 1 patient; 5.3%), and compression fractures (n = 5; 26.3%). Conclusions: High-dose CIRT is a promising treatment option for unresectable upper cervical chordoma.journal articl

225Ac治療薬剤開発に資する遊離225Ac除去法の基礎研究

α線放出核種を用いた最新研究についての紹介。 肝臓などに蓄積した遊離225Acの排出方法の開発を目的とし、様々なキレート剤のin vivoでの効果を比較し、実現の可能性を評価。またキレート剤の効果とその科学構造を比較することで、関連性を検討。 Ca-TTHAまたはCa-DTPAが遊離225Aｃの全身クリアランスに効果的であることが明確に。これらのキレート剤の投与は225Ａｃ標識薬から放出した遊離225Ａｃによって引き起こされる予期しない放射線被ばくを軽減し、225ＡｃＴＡＴの開発を促進するための新しい手法となる可能性がある。articl

Magnetic Sensitivity of Silicon Vacancies in 4H-SiC at Different Temperatures

Silicon vacancies (Vsi) in silicon carbide (SiC) have attracted attention because they can be used for quantum sensors (F. Fuchs et al., Nat. Com. 6: 7578　(2015)). We aim to develop Vsi magnetic sensors operating at high temperatures because of its structural stability. However, change with temperatures, especially high temperature, in optically detected magnetic resonance (ODMR) in the　ground state of Vsi, which is the basic principle of magnetic sensing, is less well understood. Here, we report the change in ODMR spectra of Vsi with different temperatures.Defects in solids for quantum technologies(DSQT)conference objec

Recovery of the laser-induced breakdown spectroscopy (LIBS) system using a ceramic microchip deteriorated by radiation for the remote elemental analysis

The radiation-induced deterioration of ceramic microchip laser properties, which limits the applications of the laser-induced breakdown spectroscopy (LIBS) system, was recovered with thermal treatment as derived by spectroscopic comparison of ceramics and single crystal (SC). Absorption in spectra was increased by radiation, and the increase was greater for ceramics than for SC in the infrared radiation (IR) region. Although for ceramics, the absorption decreased by heating and increased by cooling, no significant thermal effects were observed for SC. The effect of irradiation on the laser properties of ceramics was examined, and the reduced laser pulse energy was well recovered by heating. Since heating did not deteriorate the beam profile affecting the LIBS efficiency, the procedure was effective in recovering the diminished LIBS signal. Although, heating reduced the number of generated pulses, which affects burst-mode measurement, it was recovered by increasing pump laser. Since radiation-induced deterioration of the LIBS signal for single pulse and multi-burst mode measurements was well recovered, the processes are effective for the application of LIBS systems using radiation sensitive ceramics particularly in harsh radiation environments.journal articl

ITPA（国際トカマク物理活動）会合報告（81）

国際トカマク物理活動（ITPA）の「スクレイプオフ層とダイバータ物理」と「周辺ペデスタル物理」の二つのトピカルグループ会合が、2022年1月から2月にかけて開催された。各会合において議論した重要課題への取り組みや国際共同実験/解析の状況を、プラズマ・核融合学会誌を通して国内の研究者に報告する。articl

放射光その場観察を用いた新規金属水素化物の高温高圧合成

私たちは高温高圧下で新規水素化物の探索を進めているが、試料の反応過程を直接観察可能な放射光その場観察技術が探索研究において重要な役割を果たしている。本シンポジウム講演では高温高圧下での放射光その場観察技術を中心に発表を行う。公益社団法人日本金属学会2022年春期(第170回)講演大会conference objec

New standards for phantom image quality and SUV harmonization range for multicenter oncology PET studies

Not only visual interpretation for lesion detection, staging, and characterization, but also quantitative treatment response assessment are key roles for 18F-FDG PET in oncology. In multicenter oncology PET studies, image quality standardization and SUV harmonization are essential to obtain reliable study outcomes. Standards for image quality and SUV harmonization range should be regularly updated according to progress in scanner performance. Accordingly, the first aim of this study was to propose new image quality reference levels to ensure small lesion detectability. The second aim was to propose a new SUV harmonization range and an image noise criterion to minimize the inter-scanner and intra-scanner SUV variabilities. We collected a total of 37 patterns of images from 23 recent PET/CT scanner models using the NEMA NU2 image quality phantom. PET images with various acquisition durations of 30–300 s and 1800 s were analyzed visually and quantitatively to derive visual detectability scores of the 10-mm-diameter hot sphere, noise-equivalent count (NECphantom), 10-mm sphere contrast (QH,10 mm), background variability (N10 mm), contrast-to-noise ratio (QH,10 mm/N10 mm), image noise level (CVBG), and SUVmax and SUVpeak for hot spheres (10–37 mm diameters). We calculated a reference level for each image quality metric, so that the 10-mm sphere can be visually detected. The SUV harmonization range and the image noise criterion were proposed with consideration of overshoot due to point-spread function (PSF) reconstruction. We proposed image quality reference levels as follows: QH,10 mm/N10 mm ≥2.5 and CVBG ≤14.1%. The 10th–90th percentiles in the SUV distributions were defned as the new SUV harmonization range. CVBG ≤10% was proposed as the image noise criterion, because the intra-scanner SUV variability signifcantly depended on CVBG. We proposed new image quality reference levels to ensure small lesion detectability. A new SUV harmonization range (in which PSF reconstruction is applicable) and the image noise criterion were also proposed for minimizing the SUV variabilities. Our proposed new standards will facilitate image quality standardization and SUV harmonization of multicenter oncology PET studies. The reliability of multicenter oncology PET studies will be improved by satisfying the new standards.journal articl