scholarly journals Radiation Effect on Optical Properties of Bi-Related Materials Co-Doped Silica Optical Fibers

2020 ◽  
Author(s):  
Jianxiang Wen ◽  
Ying Wan ◽  
Yanhua Dong ◽  
Yi Huang ◽  
Yanhua Luo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Radiation Dose ◽  
Optical Fibers ◽  
Low Dose ◽  
High Dose ◽  
Verdet Constant ◽  
Doped Fibers ◽  
Dose Radiation ◽  
Co Doped ◽  
Pump Absorption

Three kinds of Bi-related materials co-doped silica optical fibers (BRDFs), including Bi/Al, Bi/Pb, and Bi/Er co-doped fibers, were fabricated using atomic layer deposition (ALD) and modified chemical vapor deposition (MCVD). Then, the effect of irradiation on the optical properties of BRDFs was investigated. The experimental results showed that the fluorescence intensity, the fluorescence lifetime of BRDFs at the 1150 nm band, increased significantly with low-dose treatment, whereas it decreased with a further increase in the radiation dose. In addition, the merit Mα values of the BRDFs, a ratio of useful pump absorption to total pump absorption, decreased with an increase of the radiation doses. The Verdet constants of different doped fibers increased up to saturation level with increases in the radiation dose. However, for a Bi-doped fiber, its Verdet constant decreased and the direction of Faraday’s rotation changed under low-dose radiation treatment. In addition, the Verdet constant increase of the Bi-doped silica fiber was much faster than that of other single mode fiber (SMF) and Pb-doped silica fibers treated with high-dose radiation. All of these findings are of great significance for the study of the optical properties of BRDFs.

scholarly journals High-dose radiation associated with improved survival in IDH-wildtype low-grade glioma

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Shuai Liu ◽  
Yanwei Liu ◽  
Guanzhang Li ◽  
Jin Feng ◽  
Li Chen ◽  
...  
Keyword(s):  
Overall Survival ◽  
Survival Analysis ◽  
Radiation Dose ◽  
Frontal Lobe ◽  
Low Grade Glioma ◽  
Molecular Characteristics ◽  
High Dose ◽  
Low Grade ◽  
Multivariate Survival ◽  
Dose Radiation

Abstract Background As molecular advances have deepened the knowledge on low-grade glioma (LGG), we investigated the effect of higher radiation dose on the survival of IDH-wildtype (IDHwt) LGG. Methods In the current study, 52 IDHwt LGG patients who received radiotherapy were enrolled from the Chinese Glioma Genome Atlas dataset. Radiation doses > 54 Gy were defined as high-dose, whereas doses ≤ 54 Gy were defined as low-dose. We performed univariate and multivariate survival analyses to examine the prognostic role of high-dose radiotherapy. Results In total, the radiation dose ranged from 48.6 Gy to 61.2 Gy, with a median of 55.8 Gy, and 31 patients were grouped into high-dose radiation. Univariate survival analysis indicated that high-dose radiotherapy (p = 0.015), tumors located in the frontal lobe (p = 0.009), and pathology of astrocytoma (p = 0.037) were significantly prognostic factors for overall survival. In multivariate survival analysis, high-dose radiotherapy (p = 0.028) and tumors located in the frontal lobe (p = 0.016) were independently associated with better overall survival. Conclusions In conclusion, high-dose radiotherapy independently improved the survival of IDHwt LGG. This can guide treatments for glioma with known molecular characteristics.

scholarly journals Radiation Dose Optimization in Pediatric Chest CT: Major Indicators of Dose Exposure in 1695 CT Scans over Seven Years

2018 ◽  
Vol 190 (12) ◽  
pp. 1131-1140 ◽  
Author(s):  
Michael Esser ◽  
Sabine Hess ◽  
Matthias Teufel ◽  
Mareen Kraus ◽  
Sven Schneeweiß ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Low Dose ◽  
Chest Ct ◽  
Dose Optimization ◽  
High Dose ◽  
High Pitch ◽  
Pediatric Chest ◽  
Radiation Dose Optimization

Purpose To analyze possible influencing factors on radiation exposure in pediatric chest CT using different approaches for radiation dose optimization and to determine major indicators for dose development. Materials and Methods In this retrospective study at a clinic with maximum care facilities including pediatric radiology, 1695 chest CT examinations in 768 patients (median age: 10 years; range: 2 days to 17.9 years) were analyzed. Volume CT dose indices, effective dose, size-specific dose estimate, automatic dose modulation (AEC), and high-pitch protocols (pitch ≥ 3.0) were evaluated by univariate analysis. The image quality of low-dose examinations was compared to higher dose protocols by non-inferiority testing. Results Median dose-specific values annually decreased by an average of 12 %. High-pitch mode (n = 414) resulted in lower dose parameters (p < 0.001). In unenhanced CT, AEC delivered higher dose values compared to scans with fixed parameters (p < 0.001). In contrast-enhanced CT, the use of AEC yielded a significantly lower radiation dose only in patients older than 16 years (p = 0.04). In the age group 6 to 15 years, the values were higher (p < 0.001). The diagnostic image quality of low-dose scans was non-inferior to high-dose scans (2.18 vs. 2.14). Conclusion Radiation dose of chest CT was reduced without loss of image quality in the last decade. High-pitch scanning was an independent factor in this context. Dose reduction by AEC was limited and only relevant for patients over 16 years. Key Points Citation Format

scholarly journals Phosphoprotein profiles of candidate markers for early cellular responses to low-dose γ-radiation in normal human fibroblast cells

2017 ◽  
Vol 58 (3) ◽  
pp. 329-340 ◽  
Author(s):  
Ji-Hye Yim ◽  
Jung Mi Yun ◽  
Ji Young Kim ◽  
In Kyung Lee ◽  
Seon Young Nam ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Human Fibroblast ◽  
Low Dose ◽  
High Dose ◽  
Normal Human Fibroblast ◽  
Low Dose Radiation ◽  
Γ Radiation ◽  
Normal Human ◽  
Dose Radiation ◽  
In Cells

Abstract Ionizing radiation causes biological damage that leads to severe health effects. However, the effects and subsequent health implications caused by exposure to low-dose radiation are unclear. The objective of this study was to determine phosphoprotein profiles in normal human fibroblast cell lines in response to low-dose and high-dose γ-radiation. We examined the cellular response in MRC-5 cells 0.5 h after exposure to 0.05 or 2 Gy. Using 1318 antibodies by antibody array, we observed ≥1.3-fold increases in a number of identified phosphoproteins in cells subjected to low-dose (0.05 Gy) and high-dose (2 Gy) radiation, suggesting that both radiation levels stimulate distinct signaling pathways. Low-dose radiation induced nucleic acid–binding transcription factor activity, developmental processes, and multicellular organismal processes. By contrast, high-dose radiation stimulated apoptotic processes, cell adhesion and regulation, and cellular organization and biogenesis. We found that phospho-BTK (Tyr550) and phospho-Gab2 (Tyr643) protein levels at 0.5 h after treatment were higher in cells subjected to low-dose radiation than in cells treated with high-dose radiation. We also determined that the phosphorylation of BTK and Gab2 in response to ionizing radiation was regulated in a dose-dependent manner in MRC-5 and NHDF cells. Our study provides new insights into the biological responses to low-dose γ-radiation and identifies potential candidate markers for monitoring exposure to low-dose ionizing radiation.

scholarly journals GC-16HYPERSENSITIVITY OF INTRACRANIAL GERMINOMAS FOR LOW-DOSE RADIATION: RELATIONSHIP BETWEEN DIAGNOSTIC RADIATION DOSE AND VOLUMETRIC CHANGES BEFORE CHEMORADIOTHERAPY

2016 ◽  
Vol 18 (suppl 3) ◽  
pp. iii45.3-iii45
Author(s):  
Naoki Kagawa ◽  
Ryuichi Hirayama ◽  
Yasunori Fujimoto ◽  
Yasuyoshi Chiba ◽  
Chisato Yokota ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Low Dose ◽  
Low Dose Radiation ◽  
Diagnostic Radiation ◽  
Dose Radiation

Low-Dose Versus High-Dose Radiation Therapy for the Palliation of Dysphagia From Esophageal Cancer: A Multicenter Retrospective Cohort Study

2020 ◽  
Vol 10 (4) ◽  
pp. e255-e263 ◽  
Author(s):  
Bram D. Vermeulen ◽  
Paul M. Jeene ◽  
Jasmijn Sijben ◽  
Robin Krol ◽  
Heidi Rütten ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Radiation Therapy ◽  
Cohort Study ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Low Dose ◽  
High Dose ◽  
Dose Radiation

The Effects of Low Dose Radiation and High-dose-rate Radiation with Amifostine in a Large-scale Mouse Study

2009 ◽  
Vol 75 (3) ◽  
pp. S557
Author(s):  
M. Alcantara ◽  
D. Paunesku ◽  
T. Paunesku ◽  
A. Wahl ◽  
Y. Kataoka ◽  
...  
Keyword(s):  
Dose Rate ◽  
Large Scale ◽  
Low Dose ◽  
High Dose Rate ◽  
High Dose ◽  
Low Dose Radiation ◽  
Mouse Study ◽  
Dose Radiation

Phase II Trial of High-Dose Conformal Radiation Therapy With Concurrent Hepatic Artery Floxuridine for Unresectable Intrahepatic Malignancies

2005 ◽  
Vol 23 (34) ◽  
pp. 8739-8747 ◽  
Author(s):  
Edgar Ben-Josef ◽  
Daniel Normolle ◽  
William D. Ensminger ◽  
Suzette Walker ◽  
Daniel Tatro ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Radiation Therapy ◽  
Radiation Dose ◽  
Hepatic Artery ◽  
Median Survival ◽  
Phase Ii Trial ◽  
High Dose ◽  
Hepatobiliary Tumors ◽  
Historical Controls ◽  
Dose Radiation

Purpose A phase II trial was conducted to determine if high-dose radiation with concurrent hepatic arterial floxuridine would improve survival in patients with unresectable intrahepatic malignancies. Patients and Methods Three-dimensional conformal high-dose radiation therapy was delivered concurrently with hepatic arterial floxuridine in 128 patients. The radiation dose was based on a normal-tissue complication probability model and subjected the patient to an estimated maximum risk of radiation-induced liver disease of 10% to 15%. The study design provided more than 80% power to detect a two-fold increase in median survival compared with historical controls at a 5% significance level. Results The median radiation dose delivered was 60.75 Gy (1.5-Gy fractions bid). At a median follow-up time of 16 months (26 months in patients who were alive) the median survival was 15.8 months (95% CI, 12.6 to 18.3 months), significantly longer than in the historical control. The actuarial 3-year survival was 17%. The total dose was the only significant predictor of survival. Primary hepatobiliary tumors had a significantly greater tendency to remain confined to the liver than did colorectal cancer metastases. Overall toxicity was acceptable, with 27 patients (21%) and 11 patients (9%) developing grade 3 and 4 toxicity, respectively, and one treatment-related death. Conclusion The results suggest that, compared with historical controls, high-dose focal liver irradiation with hepatic artery floxuridine prolongs survival in patients with unresectable chemotherapy-refractory metastatic colorectal cancer and primary hepatobiliary tumors. This provides a rationale for intensification of local therapy for unresectable hepatobiliary cancers and integration of this regimen with newer systemic therapy for patients with colorectal cancer.

scholarly journals Effects of Low Dose Fractional Radiation on Chemosensitivity of Gemcitabine-Resistant Human Pancreatic Cancer SW1900/GZ Cell

2021 ◽  
pp. 1-6
Author(s):  
Danni XU ◽  
Yanda LU ◽  
Fengxiang Han ◽  
Chunxiang Luo ◽  
Fen Huang ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Cell Line ◽  
Low Dose ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Human Pancreatic Cancer ◽  
High Dose ◽  
Drug Resistant ◽  
Protein Levels ◽  
Dose Radiation

Objective: To investigate whether low-dose fractionated radiation (LDFRT) could enhance gemcitabine sensitivity in drug-resistant human pancreatic cancer SW1900/GZ cell, and to further explore the underlying mechanism. Methods: Gemcitabine-resistant human pancreatic cancer SW1900 cell line (SW1900/GZ) was induced by high concentration gemcitabine intermittent shock in vitro. The cell counting kit 8 (CCK8) was used to determine SW1900/GZ cell lines. SW1900/GZ cells were divided into six groups as follows: control, LDFRT, high dose radiation (HDRT), gemcitabine (GEM), low dose fractional radiation plus gemcitabine (LDFRT+ GEM) and high dose radiation plus gemcitabine (HDRT+ GEM) groups. The rate of apoptosis was determined by flow cytometry (FCM). Protein levels of multidrug resistance gene (MDR) and multidrug resistance-related protein gene (MRP) were examined by Western blotting. Results: The results of CCK8 test showed that the half-maximal inhibitory concentration (IC50) of non-drug-resistant cell line SW1900 and drug-resistant cell line SW1990/GZ were 230.4ng/ml and 856.6ug/ml respectively. The IC50 of SW1990/GZ was 3700 times more than the former. LDFRT significantly promoted apoptosis in SW1900 cells. Moreover, in the LDFRT group, protein levels of MDR and MRP were markedly decreased. Conclusion: This study established an effective gemcitabine-resistant cell line SW1900 of human pancreatic cancer (SW1900/GZ cell line). LDFRT sensitizes resistant SW1900/GZ pancreatic cancer cell to gemcitabine through down-regulation the expression of MDR and MPR proteins.

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