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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"low dose rate"”.
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Continuous low dose rate irradiation of the rat brain
… time may be achieved with the use of continuous low dose rate external beam radiotherapy, where the treatment is administered over a 12 to 24 hour period. A relationship between fractionated and continuous low dose rate irradiation has been reported for skin, however, no such relationship has …
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Irradiators for measuring the biological effects of low dose-rate ionizing radiation fields
… field. Particle type, energy spectrum, and dose-rate all affect biological response per unit dose. This thesis describes methods of spectral analysis, dosimetry, biological assays, and mathematical modeling for determining the relative biological response for low dose-rate fields. The …
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Characterization of the Neutron Irradiation System for use in the Low-Dose-Rate Irradiation Facility at Sandia National Laboratories
… for use at Sandia National Laboratories (SNL) Low Dose Rate Irradiation Facility (LDRIF). With a total activity of 0.3 TBq (9 Ci), the source consisted of three recycled 241AmBe sources of different activities that had been combined into a single source. The source in its polyethylene shielding …
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Fast Monte Carlo Cell-By-Cell Simulation of Radiation-Induced DNA Damage, Chromosome Aberrations, and Cell Death for Low-Dose-Rate Brachytherapy Sources
… an extension of the TOPAS modeling tool, allows the generation of standard DNA damage (SDD) files on a particle-by-particle and cell-by-cell basis. MEDRAS, a mechanistic DNA repair and survival model, is capable of calculating various types of chromosome aberrations and determining whether a …
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Dose-rate-effects in XRCC1 wild-type and mutant CHO cell lines using An ²⁴¹AM source
This work explores the effects of low-dose-rate radiation on both the AA8 (wild-type CHO cells) and EM9 (XRCC1 null CHO mutants) cell lines. In particular, this study performed clonogenic survival and growth assays to determine the radiations/ effect on the cells proliferative capacity. It was …
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RADIATION-INDUCED CHROMOSOME INSTABILITY AND INTERCELLULAR COMMUNICATION: THE ROLE OF DOSE RATE AND IMPLICATIONS FOR CARCINOGENESIS
The biological risks associated with low dose and low dose rate (LDR) radiation exposures are not yet well characterised. Experimental studies indicate that in addition to biological effects resulting from direct DNA damage, a variety of non-DNA targeted effects (NTE) including radiation-induced …
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Encapsulated Contrast Agent Markers For Mri-Based Post-Implant Dosimetry
<p>Low-dose-rate prostate brachytherapy involves the implantation of tiny radioactive seeds into the prostate to treat prostate cancer. The current standard post-implant imaging modality is computed tomography (CT). On CT images, the radioactive seeds can be distinctively localized but delineation …
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Development of dense scintillating hard fluoride glasses for the electromagnetic caorimeter of the proposed compact muon solenoid
… developed, it is optimised for materials with low light output. An alternative acquisition system which used a Multi-Channel Scaler has been critically evaluated for this application. A low dose rate (1.2 rads- I) 60CO irradiation has been used to determine the radiation tolerance of the …
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Impact of Phytosanitary Irradiation on Polar Antioxidants in Peels of ‘Granny Smith’ Apples
… changes in vitamin C content immediately following irradiation. However, after four months of storage, gamma-treated peels showed a decrease in ascorbic acid and an increase in dehydroascorbic acid, while e-beam and X-ray treatments did not show significant changes. Phenolic content initially …
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Ion dosimetry for radiobiology experiments employing laser-accelerated beams
Cell behaviour in ultra-high dose rate environments, characteristic of laser driven ion acceleration, is a largely unexplored field of research, the understanding of which is crucial to the development of an all-optical delivery of ion beams suitable for cancer treatment. In conducting cell …
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Advanced brachytherapy dosimetric considerations
… was investigated with emphasis on evaluations of dose distributions and shielding considerations for both photon- and neutron-emitting radionuclides. Monte Carlo simulation methods were employed to calculate dose distributions for virtual and commercial brachytherapy sources. Radionuclides studied …
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Absolute Dose Verification in Intensity Modulated Radiation Fields
… is to device a method for measuring the absolute dose for Intensity modulated radiation fields. An accurate verification and physical measurement of the computed absolute dose in Intensity modulated radiation therapy (IMRT) is a challenging task. There are many sources of errors associated with …
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Development of Fully Balanced Ssfp and Computer Vision Applications For Mri-Assisted Radiosurgery (Mars)
… among all other therapeutic options for low to intermediate risk patients of prostate cancer. In low-dose-rate (LDR) brachytherapy, verifying the location of the radioactive seeds within the prostate and in relation to critical normal structures after seed implantation is essential to …
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Effects of AFEX Pretreatment, Denisifcation and Storage on Ethanol Yields of Corn Stover, Switchgrass and Prairie Cordgrass
… with an innovative densification method allowed reduced costs per unit. Five conditions were examined: untreated (control), AFEX pretreated, pretreated/densified, pretreated/stored, and pretreated/densified/stored. Two enzyme doses of cellulase and β-glucosidase were employed, using a …
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Investigating the Effects of Particle Radiation Exposure on Lung Carcinogenesis
… side effects of proton radiation to equivalent doses of X-rays in the initiation and progression of premalignant lesions in a transgenic mouse lung cancer model (K-rasLA1). We show proton irradiation causes more complex DNA damage that is not completely repaired resulting in increased oxidative …
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Evaluation of Presage® Dosimeters For Brachytherapy Sources and The 3D Dosimetry and Characterization of The New Agx100 125I Seed Model
… techniques, method of 3D dosimetry for treatment dose verifications would better ensure accurate patient radiotherapy treatment. This study was aimed to first evaluate the 3D dose distributions of the low-dose rate (LDR) Amersham 6711 Oncoseed<sup>TM</sup> using PRESAGE<sup>®</sup> dosimeters to …
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Investigations on the antifungal and cancer modulating properties of extracts from selected species of Tulbaghia
… mixtures and may validate disease control strategies with increased biological activity and low dose rate application. Modulation studies of hepatic drug metabolizing enzymes and oxidative properties of AI/ium sativum, Tulbaghia violacea and T. alliacea in male Fischer rats were also …
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Assessment and Analysis of Commercial Off the Shelf Devices for Space Applications
… of technology has significantly accelerated the exploration of space. Microelectronic devices have been extensively deployed in various settings, from low-Earth orbit to deep-space missions. However, the harsh radiation environment in space exposes electronic systems to intense cosmic …