National Institutes for Quantum and Radiological Science and Technology
National Institute of Radiological Science: NIRS-Repository / 放射線医学総合研究所 学術機関リポジトリNot a member yet
37195 research outputs found
Sort by
In vivo deep-brain microscopy at submicrometer resolution with refractive index-matched prism interfaces
No full text生理研研究会記憶研究会2025にて「In vivo deep-brain microscopy at submicrometer resolution with refractive index-matched prism interfaces」の演題でポスター発表を行う。生理研研究会記憶研究会2025conference poste
Visualization of Temperature-responsive Carbon Dynamics in Apple Trees
No full textAs an effect of global warming, it is a great concern that many crops are facing a change in progress in their suitable locations for growth. In recent years, Japan has experienced high temperatures in the fall (i.e. hot fall), with many regions recording record highs in 2024. A report showed that an extended fruit growth period due to the hot fall changes the acid content and sugar concentration of apple fruits, leading to poor coloration and a decline in overall quality. Then, this matter force farmers to improve their cultivation management. To understand how hot fall affects carbon dynamics in apple trees could be an important clue to solving this matter. Using positron-emitting tracer imaging system (PETIS) to visualize translocation under environmental changes, we examined temperature-responsive carbon dynamics in apple tree.We used 80 cm tall, two-year-old apple plantlets (Malus pumila), pollinated in May and grown in a greenhouse at 28-30°C until October. Under these cultivation conditions, the apple trees not only bear fruit but also continue to develop new leaves. The plantlets were transferred to a chamber with PETIS, and temporarily exposed to 20°C for 2, 6, or 10 days before returning to 30°C, simulating short-term cooling in hot fall. After completing exposure at 20°C for a period of time and just after the shifted back to 30°C, Carbon-11 (¹¹C) gas was applied to newly developed leaves and the ¹¹C transports to branch and fruits were monitored for approximately 3 hours in each.As a result, 11C translocation from leaves to branches was observed after 2 days of 20°C-exposure, and it decreased after 6 days and further declined after 10 days. This suggests that the 6 to 10 days 20°C-exposure may have been gradually perceived as low-temperature stress, or prioritized carbon allocation to newly developed leaves, which 11C was applied. Next, we confirmed that ¹¹C translocation was reactivated under all exposure terms when the plantlets were shifted from each 20°C-exposure period back to 30°C. However, longer 20°C exposure required more time for translocation activity to resume. A similar trend was observed in fruits. Although an unknown mechanism induced by low-temperature stress would be inactivated upon shifting back to 30°C, the time required for inactivation may depend on the intensity of the induction. Additionally, some fruits did not show an obvious signal. This was thought to be due to unidentified selectivity in translocation to individual fruits, which may not have been detected during the PETIS imaging. Finally, we analyzed the changes in transport velocity when the temperature shifted from 20°C to 30°C. In the 2 days 20°C-exposure, transport velocity slightly increased, whereas after 6 days, a stronger increase was observed. However, transport velocity did not change within 3 hours of the experimental time after 10 days exposure to 20°C. All these results showed that carbon translocation was not only reactivated but also enhanced transport activity when shifted to 30°C. These results conclude that prolonged high-temperature exposure acclimatizes apples to warm environment and returning them to the 20°C in which they were once grown in Japan unexpectedly reduces transport activity. Although strict observations are required, these findings might contribute to optimizing the temperature control strategies against global warming.The 7th International Conference on Plant Vascular Biologyconference poste
Visualization of aqueous outflow channels to cerebrospinal fluid with eye drops of O-17-labeled saline
No full text我々のグループでは、過去O-17標識水を点眼により、前房に貯留することがMRIにより特定可能であることを報告している。本研究では、これをさらに追跡することで、視神経周囲の脳脊髄液にもO-17標識水が貯留し、生体における非侵襲的な方法で、房水の排出路のMRIにより描出可能であることを明らかにした。第53回 日本磁気共鳴医学会大会conference presentatio
品質確保に必要なラボワーク
No full text院内製造される放射性注射剤には無菌性が求められるが、その半減期は大変短く無菌試験結果判定前に投与することになる。そのため、放射性薬剤製造時に無菌状態を保ち、微生物汚染させないための施設衛生管理が重要である。院内製造放射性薬剤は全ロットについて最終容器充填の直前で滅菌フィルターによりろ過滅菌する。そのため、特にフィルター滅菌以降のプロセスやそこで使用する材料、資材の組み立ては、クリーンベンチ等の使用により菌の混入が生じない衛生環境で実施する必要があるが、こうした無菌環境を構築、維持するためには、製造エリア全体の衛生管理の観点から適切に仕様を決定し、無菌環境に接するバックグラウンド管理や、環境モニタリング、差圧管理が極めて重要である。本演題では、適切な管理グレードレベルの設定、及び施設のデザインや設備・装置等の適格性によってグレード管理を達成するための考え方について紹介する。日本核医学会PET核医学分科会 PETサマーセミナー2025in白山conference presentatio
Diode-based row-column multiplexing for clinical TOF-PET detectors
No full textSignal multiplexing is important to reduce the complexity and cost of clinical positron emission tomography (PET) systems. In addition, good coincidence timing resolution (CTR) is also required to improve the image quality of PET by using the time-of-flight (TOF) information. Here, we report a diode-based row-column multiplexing (RC mux) circuit for clinical TOF-PET applications. A TOF detector consists of fast-LGSO crystal 8×8 array (crystal pitch=3.2 mm, thickness=20 mm) and Hamamatsu SiPM 8×8 array (S14160-3050HS, pixel pitch=3.2 mm) with one-to-one coupling (Fig. 1(a)). Custom-made RC mux circuits were developed to reduce the SiPM channels from 64 into 16 (8 x-position + 8 y-position) with diode and resistor materials, respectively (Fig. 1(b-c)). The timing information was obtained from the meantime of the x and y signals. The multiplexed analog signals were digitized by using PETsys TOFPET2 ASIC modules with an energy window of 440-560 keV (Fig. 2(a)). The effects of the RC mux circuits on the CTR were evaluated with the same crystal and SiPM arrays (Fig. 2(b)). The CTR with the diode-multiplexing was 339 ps, which was 4.3% worse and 34.5% better than the case without multiplexing (325 ps) and with resistor-based multiplexing (456 ps). In conclusion, the diode-based RC multiplexing is a cost-effective solution for the development of clinical TOF-PET systems.The 86th JSAP Autumn Meeting 2025conference presentatio
体内老化細胞を検出・除去する放射性薬剤の開発
No full textInhibiting glutamine metabolism has been proposed as a potential treatment strategy forimproving non-alcoholic steatohepatitis (NASH). However, effective methods for assessing dynamicmetabolic responses during interventions targeting glutaminolysis have not yet emerged. Here, we developeda positron emission tomography (PET) imaging platform using L-[5-11C]glutamine ([11C]Gln) andevaluated its efficacy in NASH mice undergoing metabolic therapy with bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide (BPTES), a glutaminase 1 (GLS1) inhibitor that intervenes in the first andrate-limiting step of glutaminolysis. PET imaging with [11C]Gln effectively delineated the pharmacokineticsof L-glutamine, capturing its temporal-spatial pattern of action within the body. Furthermore, [11C]Gln PET imaging revealed a significant increase in hepatic uptake in methionine and choline deficient(MCD)-fed NASH mice, whereas systemic therapeutic interventions with BPTES reduced the hepaticavidity of [11C]Gln in MCD-fed mice. This reduction in [11C]Gln uptake correlated with a decrease in GLS1 burden and improvements in liver damage, indicating the efficacy of BPTES in mitigating NASHrelatedmetabolic abnormalities. These results suggest that [11C]Gln PET imaging can serve as a noninvasivediagnostic platform for whole-body, real-time tracking of responses of glutaminolysis to GLS1manipulation in NASH, and it may be a valuable tool for the clinical management of patients with NASHundergoing glutaminolysis-based metabolic therapy.Linyi International Symposium on Nuclear Medicine and Molecular Imaging 2024conference presentatio
Evaporative Concentration of Solution onto a Hydrophilic Spot Preserved on a Fluorine-Coated Glass Slide for High-Sensitivity TXRF Analysis
No full textTotal reflection X-ray fluorescence (TXRF) analysis is typically utilized to analyze trace ele-ments. Our research group has employed this technique to analyze uranium in solution [1]. Dur-ing the TXRF analysis of a liquid sample, several microliters of the solution were dropped onto a fluorine-coated glass slide and dried. However, the sensitivity of the measurement can be im-proved by increasing the volume of the sample dropped onto the measurable area. In principle, a solution of the same concentration can be measured with tenfold sensitivity by dropping 10 times its volume onto the same spot size. In this study, we propose a more sensitive TXRF analy-sis method by applying a fluorine coating to the outside part of a hydrophilic slide glass, except for the central spot, which allows 1 mL of the solution to be dropped.The hydrophilic surface-treated glass slide was covered on one side with polyimide tape, and the outer tape was cut off, leaving a 6 mm diameter of making area in the center. Then, a fluororesin solution (Fine Chemical Japan Co., Ltd.) was sprayed onto the surface, and after drying, the masking tape was removed. The sample was prepared by diluting a multielement standardized solution of XSTC-4470 (Spex CertiPrep Inc.) containing 10 ng/μL of uranium, and 1 mL of this solution was dropped onto the hydrophilic spot of the glass slide. The dropped solution was evaporated under redused pressure to shrink onto a 6 mm-hydrophilic spot, followed by adding 10 μL of 1 ng/μL Ga solution as an internal standard, and then dried completely. All measure-ments were performed using a TXRF spectrometer NANOHUNTER-II (Rigaku Co., Ltd.), at a tube voltage and current of 50 kV and 12 mA, respectively.As illustrated in Figure 1, the solution on the fluorine-coated area shrinks to the hydrophilic spot during the drying process. This facilitates TXRF analysis with higher sensitivity than conven-tional methods.This study was performed under the auspices of the Secretariat of the Nuclear Regulation Authority, Japan.Reference[1] T. Matsuyama, et al., Frontier in Chemistry 7 (2019) 152.The 20th International Conference on Total Reflection X-ray Fluorescence Analysis and Related Methods (TXRF2025)conference presentatio
4H-SiC中単一シリコン空孔の電気的スピン検出と光電流生成経路の決定
No full text電気的読み出し可能な半導体中量子ビットは電子・量子複合集積素子応用が期待されており、4H-SiC中シリコン空孔スピンはその候補の一つである。シリコン空孔の光電流検出磁気共鳴(PDMR)法により実現するが、単一スピンの検出は未実証であった。我々は、PDMRによる単一シリコン空孔検出の実証し、また不明であったシリコン空孔の光電流生成経路を解明した。本発表ではこれらの詳細を報告する。第86回応用物理学会秋季学術講演会conference presentatio
嗅神経芽細胞腫に対する重粒子線治療
No full text【目的】 切除不能な局所進行の嗅神経芽細胞腫に対しては放射線治療が推奨され ているが、従来の光子線治療では治療成績が十分ではなく、より効果的な局所治療 法の確立が求められている。本研究では、重粒子線治療の安全性および有効性を後 方視的に評価する。【対象と方法】 2005年12月から2022年7月に当院で重粒子 線治療を施行した切除不能の嗅神経芽細胞腫22例を対象に後方視的に解析を行っ た。全症例に対し重粒子線治療は60.8 Gyを16分割、4週間で施行された。 【結 果】 全例治療は完遂された。観察期間中央値は63.2か月（範囲：7.1–199.3か 月）であった。5年局所制御率は70.8%、全生存率は78.3%、無増悪生存率は42.0% であった。局所再発を認めた6例（27.3%）のうち、5例は照射野内再発、1例は辺 縁再発であった。頸部リンパ節転移は8例（36.4%）、遠隔転移は6例（27.3%）に 認められた。Grade 3以上の晩期有害事象は6例（27.3%）に認められた。Grade 3 の放射線誘発性脳障害は1例（4.5%）に認められた。Grade 3以上の視神経障害は 5例（22.7%）に認められ、うち3例にGrade 4の患側失明が認められた。これら重 篤な視神経障害は、照射前より腫瘍が患側視神経に近接しており、腫瘍制御のため に視神経への高線量照射を避ける事が困難であったため、治療前より出現が予測されていた。 【結論】 切除不能の嗅神経芽細胞腫に対する重粒子線治療は、許容可 能な有害事象と良好な治療効果を有しており、有望な治療選択肢となり得る。NPO法人日本歯科放射線学会第6回秋季学術大会に出席conference presentatio
Metabolic Shifts in Microscale Tumor Spheroids Detected by Hyperpolarized [1-13C]pyruvate NMR
No full textEarly detection of tumorigenesis remains a major challenge in oncology, particularly for identifying subtle metabolic alterations before macroscopic tumor development. In this study, we applied hyperpolarized (HP) [1-13C]pyruvate NMR spectroscopy to characterize energy metabolism in microscale multicellular tumor spheroids, which serve as an in vitro model for early-stage tumor growth. Murine squamous cell carcinoma (SCCVII) cells were cultured into uniform spheroids of approximately 150 μm diameter, lacking hypoxic or necrotic cores yet exhibiting marked resistance to multiple chemotherapeutic agents. HP [1-13C]pyruvate NMR revealed a pronounced increase in the conversion of pyruvate to lactate relative to monolayer cultures, indicative of enhanced aerobic glycolysis, accompanied by reduced mitochondrial oxidative activity. To evaluate broader applicability, we analyzed spheroids from two PSA-negative human prostate cancer lines, DU145 and PC-3, which displayed distinct growth morphologies and metabolic gene expression patterns. Both lines showed increased expression of LDHA and monocarboxylate transporters (MCT1, MCT4), consistent with elevated lactate production and transport. HP [1-13C]pyruvate NMR confirmed significantly higher Lac/Pyr ratios in spheroids compared to monolayer cultures, with DU145 exhibiting the largest increase. Strikingly, Lac/Pyr ratios from in vitro spheroids correlated strongly with those obtained from homogenates of xenograft tumors in mice, underscoring the translational relevance of the model. These findings demonstrate that even small tumor spheroids, in the absence of hypoxia or advanced malignant features, undergo early metabolic reprogramming detectable by HP [1-13C]pyruvate NMR spectroscopy. This approach provides a sensitive, non-radioactive means of probing tumor metabolism in vitro, potentially enabling preclinical evaluation of metabolic biomarkers, drug responses, and newly developed hyperpolarized probes without reliance on animal imaging systems. The combination of HP NMR technology with microscale spheroid models offers a practical and scalable platform for investigating the onset of tumor-associated metabolic transitions.XIIIth International Workshop on EPR in Biology and Medicineconference poste