20 research outputs found

    The History of the Dalat Nuclear Reactor

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    Undergraduate Research Opportunity Program (UROP)http://deepblue.lib.umich.edu/bitstream/2027.42/116113/1/TheHistoryofthe_Dalat_Nuclear_Reactor.pd

    Impact of variations in physical parameters on glow curves for planchet heating of TL dosimeters

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    This study consists of a theoretical analysis of the directional planchet heating of Thermoluminescent Dosimeters (TLD) with an emphasis on influence of radiation field type, TL material properties, and heating scheme parameters on the resulting glow curve. Computer software is developed to simulate the thermal conduction and TL production processes in a planchet-heated TLD chip. The results of the simulation are benchmarked to previous experimental findings for a LiF TLD and excellent agreement is obtained. The system thermophysical parameters and initial depth-dose distribution in the TLD are varied and the position of the main glow peak and integral glow are examined. A demonstration is given of how a set of thermophysical parameters may provide information about the depth-dose distribution in the TLD and how variation in the values of these parameters may limit the reconstruction of this depth-dose information.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31122/1/0000018.pd

    Comparison of I-131 Radioimmunotherapy Tumor Dosimetry: Unit Density Sphere Model Versus Patient-Specific Monte Carlo Calculations

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    High computational requirements restrict the use of Monte Carlo algorithms for dose estimation in a clinical setting, despite the fact that they are considered more accurate than traditional methods. The goal of this study was to compare mean tumor absorbed dose estimates using the unit density sphere model incorporated in OLINDA with previously reported dose estimates from Monte Carlo simulations using the dose planning method (DPMMC) particle transport algorithm. The dataset (57 tumors, 19 lymphoma patients who underwent SPECT/CT imaging during I-131 radioimmunotherapy) included tumors of varying size, shape, and contrast. OLINDA calculations were first carried out using the baseline tumor volume and residence time from SPECT/CT imaging during 6 days post-tracer and 8 days post-therapy. Next, the OLINDA calculation was split over multiple time periods and summed to get the total dose, which accounted for the changes in tumor size. Results from the second calculation were compared with results determined by coupling SPECT/CT images with DPM Monte Carlo algorithms. Results from the OLINDA calculation accounting for changes in tumor size were almost always higher (median 22%, range -1%-68%) than the results from OLINDA using the baseline tumor volume because of tumor shrinkage. There was good agreement (median -5%, range -13%-2%) between the OLINDA results and the self-dose component from Monte Carlo calculations, indicating that tumor shape effects are a minor source of error when using the sphere model. However, because the sphere model ignores cross-irradiation, the OLINDA calculation significantly underestimated (median 14%, range 2%-31%) the total tumor absorbed dose compared with Monte Carlo. These results show that when the quantity of interest is the mean tumor absorbed dose, the unit density sphere model is a practical alternative to Monte Carlo for some applications. For applications requiring higher accuracy, computer-intensive Monte Carlo calculation is needed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90433/1/cbr-2E2011-2E0965.pd

    PYI (Presidential Young Investigator Award)

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    Issued as Annual progress report, and Final report, Project E-25-M1

    Mixed field dosimetry using focused and unfocused laser heating of thermoluminescent materials

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    Issued as Progress report, Project E-25-X1

    Mammography and Breast Cancer Research

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    Intelligent Radiation Awareness Drone: Creation of an Unmanned Aerial Vehicle with Radiation Hazard-Guided Navigation

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    Radiation surveillance over large areas is necessary to measure background environmental radiation levels or respond to nuclear accidents or terrorist events. Current methods of radiological surveying are time consuming and resource demanding and would be greatly improved with the use of an unmanned aerial vehicle (UAV) with a radiation-detecting payload. The efficiency of such a UAV can be increased by using a hazard-guided navigation algorithm which actively searches for hazards using all available information, instead of using a standard rectilinear search pattern. The growth of the drone hobbyist community has enabled an interdisciplinary team of undergraduate students to design and build an Intelligent Radiation Awareness Drone (iRAD). iRAD is a multicopter drone containing a complex integrated system which will include a small radiation-detection payload and be capable of autonomous operation. The project aims to create a more efficient method of radiological surveying and provide continued research opportunities for undergraduate students in nuclear engineering and related fields.NAhttp://deepblue.lib.umich.edu/bitstream/2027.42/176756/1/iRADCapstoneReport_-_Marlee_Trager.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/176756/2/iRADDesignExpo2022_-_Marlee_Trager.pd
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