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Carbon-Ion Radiation Therapy as Nonsurgical Treatment for Early-Stage Breast Cancer: 5-Year Results From the Phase 2 Part of the First Prospective Clinical Trial
No full textPurpose: To evaluate the long-term efficacy, safety, and cosmetic outcomes of carbon-ion radiation therapy (C-ion RT) as a nonsurgical treatment option for patients with early-stage breast cancer. Methods and Materials: This single-center, prospective phase 1/2 trial enrolled women aged ≥60 years with stage I (cT1N0M0), estrogen receptor-positive, human epidermal growth factor receptor type 2-negative invasive ductal carcinoma, ≤2 cm in diameter. Patients received C-ion RT at a total dose of 60 Gy (relative biological effectiveness) in 4 fractions, followed by adjuvant aromatase inhibitors. The primary endpoint was 5-year local control. Secondary endpoints included complete response (CR) rate, adverse events (AEs), cosmetic outcomes, disease-free survival, and overall survival. Imaging was used for evaluating tumor response, and follow-up was conducted for a median of 73 months. Results: Twelve patients were treated in the phase 2 component of the trial. The CR rate was 100%, with a median time to CR of 12 months (range, 4-36 months). The 5-year local control and disease-free survival rates were both 92%, and the overall survival rate was 100%. One case of in-field recurrence occurred in a patient with a high Ki-67 index. Acute grade 1 dermatitis was observed in 6 patients. No grade ≥2 acute AEs were reported. Regarding late AEs, grade 1 rib fractures (n = 2) and grade 1 mastitis-related pain (n = 3) were managed conservatively. Magnetic resonance imaging revealed subclinical pectoral muscle inflammation in 7 cases. All patients except one (who underwent mastectomy due to recurrence) maintained excellent cosmetic outcomes.journal articl
A practical method for synthesizing [11C]methanesulfonyl chloride as radiolabeling agent
No full textMethanesulfonyl chloride (CH3SO2Cl) is well known to be reactive with amines, alcohols and phenols. It has been reported that [11C]CH3SO2Clwas synthesized by 1) chaging [11C]CH3I into [11C]CH3Li and then treatment with sulfuryl chloride. 2) changing [11C]CH3I into [11C]CH3SH, followed by oxidization with Cl2 or MnO2 etc.1) However, the radiochemical yields of [11C]CH3SO2Cl by these methods remained unstable and some used agents are difficult to handle. Here, we reported a practical method for synthesizing [11C]CH3SO2Cl as a radiolabeling agent via [11C]CH3I.欧州分子イメージング学会（EMIM2026）conference poste
Muonium as a probe of point defects in type-Ib diamond
No full textMuonium (Mu), a bound state of a positively charged muon and an electron, can diffuse through crystal lattices and interact with defect centers in insulators and semiconductors. We demonstrate that this Mu's diffusive property can be used to probe defects in a diamond crystal lattice; specifically, substitutional nitrogen atoms (Ns0) and nitrogen-vacancy (NV) centers in type-Ib diamond. Upon interaction with these defects, Mu can exchange its electron's spin or change its charge state, which result in muon spin relaxation. However, muons in diamond (and semiconductors in general) can be in a few distinctive muonium states, with each state contributing to the muon signal. In addition, these states can undergo site and charge exchange interaction, forming a dynamic network. Hence, to study the Mu interaction with point defects, the muon data have to be deconvoluted to isolate signals from the diffusing species. To achieve this goal, we have modeled the Mu state exchange dynamics and numerically simulated the time evolution of muon spin polarization by the density matrix method. With a global curve fit to a set of longitudinal field scan data, one can extract the Mu transition rates that involve interaction with the defect centers. The diffusing tetrahedral interstitial Mu was found to interact with the paramagnetic Ns0 center via electron spin exchange. In contrast, they are converted to form a diamagnetic center upon interaction with the negatively charged NV center.journal articl
The strength of the general expectation that something will happen to me moderates the effects of weakness in the optimistic prediction of a sense of hopelessness
No full textAlthough optimism and pessimism are not one-dimensional concepts, the patterns that may exist in the combination of the two strengths has not been investigated. We implemented an online survey to explore individual patterns of negative and positive predictions concerning the near or distant future. Several patterns emerged: high expectations of both positive and negative events, low expectations for both types of event, and higher positive predictions than negative predictions, among others. The cluster that exhibited low expectations for both and the cluster with higher negative than positive predictions showed higher hopelessness scores than the other clusters. By contrast, the clusters with higher positive than negative predictions were the least hopeless. Therefore, we hypothesize that optimistic predictions have a negative effect on hopelessness, but that this effect is moderated by the strength of general expectation, including positive and negative predictions. The results of hierarchical multiple regression analysis and simple slope analysis showed a moderating effect of general expectation on the effect of optimistic prediction on hopelessness, supporting this hypothesis. The results suggest that strengthening optimistic prediction and general expectation is necessary to reduce hopelessness and to bring hope.conference pape
In vivo quantitative assessments with [11C]T-278, a PET imaging agent for diacylglycerol kinase gamma, in nonhuman primate brain
No full textDiacylglycerol kinase (DGK) is an enzyme catalyzing ATP-dependent conversion of diacylglycerol to phosphatidic acid. Among DGK subtypes, DGKγ is localized in the brain and plays important roles in the central nervous system, although its detailed functions remain unknown. Recently, [11C]T-278 was developed as a selective positron emission tomography (PET) imaging agent for DGKγ. This study aimed to conduct the first quantitative analysis using PET with [11C]T-278 in nonhuman primate brains. In rhesus monkeys, compartmental analyses showed superior goodness-of-fit in two-tissue compartment model than one-tissue compartment model. Full kinetic analysis of [11C]T278 yielded reliable estimates of the total distribution volume (VT) values across various brain regions, showing a strong correlation (slope = 1.07, r > 0.995) with VT value derived from Logan GA. Furthermore, time-stability analysis for VT estimations showed small variations (< 5%) between 70 and 90 min of scan durations across most regions of interest. This study provides the first in vivo visualization of DGKγ in monkey brain using quantitative PET analysis with [11C]T-278.journal articl
Enhanced bulk-etch-rate of gamma irradiated PADC detector expressed by the radiation chemical yield of hydroxyl group
No full textEnhanced bulk-etch-rate of PADC (polyallyl diglycol carbonate) detectors exposed to gamma rays has been found to be described well as an exponential function of the product of the radiation chemical yield of hydroxyl group (GOH) and the adsorbed dose (D) at different dose-rates between 0.41 and 8.14 Gy/s. The examined absorbed doses were ranging from 30 to 100 kGy, comparable with the local dose in proton tracks. By matching the bulk-etch-rates and the GOH values obtained under identical conditions on dose-rate, the following equation was derived for the relative bulk-etch-rate, Virra/Vb = exp(y･GOH･D), where, Virra and Vb denote the bulk-etch-rates after and before gamma irradiations, respectively, and y is an experimentally obtained constant in a unit of kg/mol, with a value of y = 5.98. In this relation, significant dose-rate dependence is explained as the dose-rate dependence of the GOH value. This means that the radiation damage that increases the bulk-etch-rate is the hydroxyl group itself, and y appears as a constant specific to PADC which relates the damage to bulk-etch-rate. Here, y is termed the “etching coefficient ".journal articl
3d遷移金属における第一原理バンド計算に基づいた内殻X線光電子分光－磁気円二色性の理論研究
No full textX線光電子分光－磁気円二色性（XPS-MCD）は放出光電子の収量が入射するX線のヘリシティによって異なる現象である．実験で観測されるXPS-MCDスペクトルは物質ごとに特徴的な形状を有しており，先行理論研究では原子多重項理論を用いることで再現されてきた[1]．しかし，原子多重項理論では強磁性金属において重要なバンド構造が考慮されておらず，それを補うために非常に多くのパラメータ操作が必要となる．そこで我々は，第一原理バンド計算を取り入れたXPS-MCD計算方法を開発した．第39回日本放射光学会年会放射光科学合同シンポジウムconference presentatio
Changes in yields of water radiolysis products in the presence of hydrogenated nanodiamonds under X-rays: Significant increase of hydrogen peroxide
No full textIn this work, we investigate how hydrogenated nanodiamonds (NDs) influence the radiolytic formation of hydrogen peroxide (H₂O₂) and OH radicals (·OH) under X-rays to understand their potential roles as radiosensitizer. To do so, changes in yields of H₂O₂ and ·OH in the presence of hydrogenated nanodiamonds (NDs) under X-rays are explored. Yields of H₂O₂ are quantified by Ghomley technique. Yields of H₂O₂ increase with the concentration of NDs under both oxygenated and de-oxygenated conditions. This enhancement is attributed to the structured adsorbed water layer at the ND surface, which alters secondary radical recombination pathways and promotes H₂O₂ formation. Additionally, yields of ·OH are evaluated using Amplex Red solution. Yields of ·OH do not vary in the presence of NDs. This finding indicates that NDs do not decompose H₂O₂, the dominant route to additional ·OH generation in nanoparticle-enhanced systems. Overall, while NDs do not amplify indirect action via ·OH, their modulation of H₂O₂ yields would still influence downstream oxidative processes and warrants further biological investigation.journal articl
Silicon's cosmic comeback: Temperature-dependent performance and radiation stability of ultra-thin silicon heterojunction solar cells for space applications
No full textGrowing demand for cost-effective satellites has renewed interest in silicon (Si) cells for space missions. However, these cells experience significant radiation-induced performance loss, which can be mitigated using ultrathin wafers. Recently, ultra-thin Si heterojunction (SHJ) cells have emerged as strong candidates for low-cost, lightweight satellites. Their behaviour under space-relevant temperatures and air mass zero conditions, before and after electron irradiation, is therefore essential to understand. This study examines the temperaturedependent performance of ultra-thin (50 μm) SHJ cells under such conditions and compares their behaviour to 180-μm SHJ cells and cell structures without heterojunctions. We find that the performance of SHJ cells drops sharply at low temperatures regardless of wafer thickness, dominated by reduced fill factor, whereas structures without heterojunctions show linear improvement as temperature decreases. Notably, irradiated ultra-thin SHJcells show a self-curing capability after annealing at 80 ◦C, enabling partial performance recovery even during electron irradiation in space. Additionally, their specific power surpasses that of the other structures across -20 ◦C to 80 ◦C. The established models reproduce the experimental trends, offering deeper insight into their low-temperature behaviour. These findings reveal a low-temperature performance threshold for SHJ cells and underscore their importance for evaluating and optimising them in space applications.journal articl
MVI-targeted Carbon-ion Radiotherapy Combined with Immunotherapy for Advanced Hepatocellular Carcinoma: Phase Ib DEPARTURE Trial
No full textPurposeAdvanced hepatocellular carcinoma (HCC) with macrovascular invasion (MVI) carries an extremely poor prognosis, necessitating novel therapeutic strategies. This phase Ib trial evaluated the safety and preliminary efficacy of combining carbon-ion radiotherapy (C-ion RT) with immune checkpoint inhibitors (ICIs) in patients with advanced HCC with MVI.Patients and MethodsFifteen patients with MVI-positive advanced HCC were enrolled (Cohort A: durvalumab monotherapy, n = 3; Cohort B: durvalumab plus tremelimumab, n = 12). C-ion RT (60 Gy, 4 fractions) was delivered to the MVI-containing primary tumor, while systemic therapy with durvalumab (+ tremelimumab) was administered concurrently. The primary endpoints included dose-limiting toxicities (DLTs) and adverse events (AEs). Secondary endpoints included progression-free survival (PFS) and overall survival (OS).ResultsNo DLTs were observed, and the combination exhibited a manageable safety profile. The most common adverse events were pyrexia, rash, and elevated lipase levels. Grade 3–4 AEs occurred in 53.3%, including cytokine release syndrome (CRS) and meningitis. Median PFS and OS were 4.7 and 10.4 months, respectively. While C-ion RT achieved effective local control of irradiated lesions, non-irradiated lesions showed limited systemic immune responses.ConclusionsThe combination of MVI-targeted C-ion RT and ICIs demonstrated safety and effective local tumor control in advanced HCC. This novel approach of selective irradiation to MVI-containing tumors, combined with systemic immunotherapy, warrants further investigation to optimize the synergistic effects and enhance systemic efficacy in this poor-prognosis population.Impact and implicationsAdvanced hepatocellular carcinoma (HCC) with macrovascular invasion (MVI) has a poor prognosis, highlighting the need for new therapeutic strategies. Our phase Ib study suggests that carbon-ion radiotherapy (C-ion RT) targeting MVI combined with immune checkpoint inhibitors is feasible and achieves sustained local tumor control. RNA sequencing revealed that immune activation pathways were enriched in responders, while resistance was associated with mesenchymal and angiogenesis signatures. These results reinforce the potential of MVI-targeted irradiation combined with ICIs as a promising treatment strategy for this high-risk patient population, warranting further investigation to improve systemic tumor control.journal articl