National Institutes for Quantum and Radiological Science and Technology
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Hyperpolarized MRI theranostics in cancer
No full textHyperpolarized magnetic resonance imaging (MRI) has emerged as a transformative tool in cancer diagnostics, enabling real-time, non-invasive assessment of tumor metabolism. By employing hyperpolarized molecular probes, such as [1-13C]pyruvate, energy metabolism and metabolic changes associated with malignancy in tumors can be visualized, providing key insights into tumor aggressiveness, heterogeneity, and treatment response. In addition to their preclinical and clinical applications in cancer diagnostic imaging, some molecular probes can be used as potentiators of cancer therapy. This perspective article explores the potential use of hyperpolarized magnetic resonance spectroscopic imaging (MRSI) in conjunction with cancer treatment. Notably, the direct application of hyperpolarized molecular probes immediately after imaging to enhance DNA-targeted cancer therapies, including chemotherapeutic drugs and radiotherapy, is termed “hyperpolarized MRI theranostics in cancer.” In this novel approach, metabolic and physiological intratumoral changes induced by biomolecular probes are used to enhance the efficacy of subsequent therapeutic interventions. Additionally, future prospects for advancements in oncology enabled by hyperpolarized MRI are discussed.journal articl
不定性を基盤とする他者や世界への働きかけ
No full textThis article explores the cognitive potential of "indeterminacy", its relationship with adversity, and its empirical testability. It begins by revisiting the notion of "quasi-magical thinking," illustration how indeterminacy can underlie the belief that one's actions and decisions may influence others and the world. The discussion then incorporates empirical findings from quantum probabilistic modeling, cognitive experiments, and neuroscience, highlighting new directions and a broader scope for cognitive research.journal articl
Phonon-enhanced spin-dependent Seebeck effect in magnetic carbon films
No full textDisordered carbon offers untapped potential for spin caloritronics. We report a phonon-enhanced spin-dependent Seebeck effect (SDSE) in a magnetic carbon film (MCF) with graphene nano-crystallites (10 nm), interfaced with Pt. In a longitudinal setup, the transverse thermoelectric voltage (VISHE/ΔT) peaks at ~30 μV/K at 220 K, driven by a thermally induced spin current via the inverse spin Hall effect. Raman spectroscopy reveals a coincident G-band redshift peak, suggesting a phonon-spin resonance unique to MCF’s hybrid structure. X-ray absorption spectra confirm stable sp2 states, potentially mediating this effect. A multiple-sample study in addition reveals that smaller crystallites enhance SDSE. Unlike pristine graphene or insulators, MCF’s weak ferromagnetism and phonon dynamics yield an unconventional spin-thermal regime. This finding redefines carbon’s role in spin caloritronics, with tunable nano-crystallite size as a design parameter.journal articl
Hydronephrosis Caused by Polyglycolic Acid Spacer Placement Prior to Carbon Ion Radiotherapy for Local Recurrence of Rectal Cancer: Case Report.
No full textCarbon-ion radiotherapy (CIRT) for pelvic recurrent rectal cancer has recently attracted attention due to its excellent therapeutic outcomes. A spacer is often inserted before CIRT to ensure a certain distance between the recurrent lesion and the adjacent intestine. We report a case of hydronephrosis due to ureteral stenosis after laparoscopic insertion of a polyglycolic acid (PGA) spacer.journal articl
Charge-weighted quality factors based on LET for practical dose assessment of space radiation
No full textWe demonstrate a new charge weighted quality factor, noted Q*, based on the practical application of particle linear energy transfer (LET) and charge (Z)-dependent quality factors for LET-based radiation dosimetry in space. Z contribution factors are defined according to the energy spectra of galactic cosmic rays (GCRs). The Z-weighted quality factor depending solely on the LET (Q*) under solar minimum conditions in free space differs by only a few percent from values obtained with spacecraft shielding or during the solar maximum spectrum. Q* values based on various biological endpoints exhibit peaks at higher LETs than those defined in ICRP-60. The reduced contribution of GCR heavy components under Q*, compared to QICRP of ICRP-60, suggests that current dose assessments may be overestimated. The proposed Q* approach is applicable to different LET- and Z-dependent quality factors, and provides practical dose evaluation using LET measurements.journal articl
Carbon Ion Radiotherapy for Retroperitoneal Sarcoma: A Single-Institution Study.
No full textSurgery remains the mainstay of treatment for retroperitoneal sarcoma (RPS); however, definitive therapeutic strategies for patients with insufficient surgical margins and unresectable disease owing to locally advanced RPS remain unclear. Carbon ion radiotherapy (CIRT) has been employed in patients with unresectable RPS. This study aimed to evaluate the effectiveness of CIRT in this patient population.journal articl
Internal Dose Assessment in a Plutonium Internal Contamination Accident at JAEA’s Oarai Research and Development Center
No full textObjectives: On June 6, 2017, an accident occurred at the JAEA’s Oarai Research and Development Center, where 5 workers inhaled plutonium. This study aims to evaluate the validity of theinternal dose assessments conducted by the QST and to share the findings with the dosimetrycommunity.Methods: In vivo measurements (lungs and liver) and bioassays were performed. The particlesize of the inhaled material was estimated based on the ratio of early fecal excretion to residuallung content. The absorption types of Pu and 241Am were evaluated using urinary excretionlevels from bioassay results of early fecal and pre-Ca- DTPA urine samples.Results: The estimated particle sizes of the inhaled materials were over 10 μm and severalmicrometers for 2 workers, respectively. The absorption types were evaluated as intermediatebetween M (Moderate) and S (Slow). A change in urinary excretion levels between before andafter Ca-DTPA administration was observed, with the most significant reduction occurring afterthe initial treatment, followed by smaller changes.Conclusions: The internal dose assessments for the 5 workers were confirmed to be conservatively conducted within a reasonable range. Comprehensive individual monitoring in cases ofinternal contamination by actinide is crucial to reducing uncertainties in dose assessment.journal articl
Experimental assessment of novel PET detector components for online imaging of radioactive ion beams
No full textObjective. This work aims to evaluate the ability of novel detector components to measure with submillimeter resolution in beam positron emission tomography (PET) signals produced by 10C and 11C radioactive ion beams stopped in PMMA targets and to validate a simulation toolkit for reproducing beam physics and PET detector responses within the framework of the biomedical applications of radioactive ion beam (BARB) project. Approach. The PET system response was assessed by visualizing the radioactive distributions of the beams stopped in tissue surrogate phantoms, and the capacity of the simulation toolkit was evaluated by comparing the experimental results with simulations, both for the depth-dose distribution and PET imaging. Main results. The detector assembly accurately visualized the PET signal with submillimeter resolution, achieving theobjective of measuring the difference in the positron range between 10C and 11C. The simulation toolkit effectively reproduced the beam characteristics and detector responses, showing a high degree of agreement between the simulated and experimental PET profiles under different beam delivery conditions. Significance. These findings demonstrate the precision and reliability of thenovel in-beam PET detector technology and simulation toolkit for small animals, establishing a solid foundation for the second phase of the BARB project, which involves preclinical irradiation of living mice.journal articl
Characterization of 237Np and Pu isotopes in fallout and soil reference materials using SF-ICP-MS
No full textNeptunium-237 (237Np) is one of the most hazardous radionuclides of public concern due to its extreme toxicity and environmental mobility. It is necessary to measure ultra-trace levels of 237Np in environmental samples accurately with enough precision to understand its behavior. However, there is a general lack of Standard Reference Materials (SRMs) with characterized 237Np activity concentration, which is important for the method development and for validation tests in accurate determination of 237Np in environmental samples. In this study, 237Np activity concentrations in a fallout reference material and a soil reference material (JSAC-0471) were measured using a sector field-ICP-MS, and the atom ratio of 237Np/239Pu in it were calculated.conference pape
Potent activity of prostaglandin J2 on prostanoid DP receptors
No full textProstaglandin D2 (PGD2), an anti-inflammatory mediator, is acting through Gs-protein coupled D-type prostanoid (DP) receptors. DP receptors are not extensively distributed; in tissues, they are the least abundant among members of the prostanoid receptor family, whereas their primary ligand PGD2 is the main prostanoid in most tissues. PGD2 is dehydrated or isomerized to a number of metabolites enzymatically or nonenzymatically. To understand why many metabolites of PGD2 are produced via different pathways, regular cell-based experiments, Black/Leff operational model calculations, and in silico simulations were utilized. Here we show that, among the five metabolites of PGD2, prostaglandin J2 (PGJ2) was the most potent metabolite for DP receptors, particularly in the cAMP signaling pathway. This result was attributed to PGJ2 forming an extra and/or stronger hydrogen bond by more negatively charged carbonyl in the cyclopentene ring with DP receptors than PGD2. Therefore, when PGD2 is released into the blood, it would activate DP receptors, which are then continuously activated by PGJ2 to sustain the DP receptor/cAMP-mediated signaling pathway. Thus, the anti-inflammatory effects of PGD2 may be taken over/out competed and/or even enhanced by PGJ2. Here, PGJ2 was found to be a standout mediator of cAMP-mediated signaling pathway, which induces more potent and prolonged DP receptor activities as a biased ligand, possibly for resolving the inflammatory reaction. Moreover, since each metabolite showed different properties, these results provide insight into why many metabolites of PGD2 are produced and the miscellaneous physiological roles induced by the main prostanoid in most tissues through the least abundant DP receptors.journal articl