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Optimization Of Radiation Therapy In Time-Dependent Anatomy, W. Tyler Watkins 2013 Virginia Commonwealth University

Optimization Of Radiation Therapy In Time-Dependent Anatomy, W. Tyler Watkins

Theses and Dissertations

The objective of this dissertation is to develop treatment planning techniques that have the potential to improve radiation therapy of time-dependent (4D) anatomy. Specifically, this study examines dose estimation, dose evaluation, and decision making in the context of optimizing lung cancer radiation therapy. Two methods of dose estimation are compared in patients with locally advanced and early stage lung cancer: dose computed on a single image (3D-dose) and deformably registered, accumulated dose (or 4D-dose). The results indicate that differences between 3D- and 4D- dose are not significant in organs at risk (OARs), however, 4D-dose to a moving lung cancer target ...


Decline In Health For Older Adults: Five-Year Change In 13 Key Measures Of Standardized Health, Paula Diehr 2013 University of Washington

Decline In Health For Older Adults: Five-Year Change In 13 Key Measures Of Standardized Health, Paula Diehr

Paula Diehr

Background. The health of older adults declines over time, but there are many ways of measuring health. It is unclear whether all health measures decline at the same rate or whether some aspects of health are less sensitive to aging than others. Methods. We compared the decline in 13 measures of physical, mental, and functional health from the Cardiovascular Health Study: hospitalization, bed days, cognition, extremity strength, feelings about life as a whole, satisfaction with the purpose of life, self-rated health, depression, digit symbol substitution test, grip strength, activities of daily living, instrumental activities of daily living, and gait speed ...


Epid-Based Dose Verification For Adaptive Radiotherapy, Joseph Gardner 2012 Virginia Commonwealth University

Epid-Based Dose Verification For Adaptive Radiotherapy, Joseph Gardner

Theses and Dissertations

Dose verification is a critical component of adaptive radiotherapy, as it provides a measurement of treatment delivery success. Based on the measured outcome, the plan may be adapted to account for differences between the planned dose and the delivered dose. Although placement of an EPID behind the patient during treatment allows for exit dosimetry which may be used to reconstruct the delivered patient dose via backprojection of the fluence, there have not been any studies examining the basic assumption of backprojection-based dose verification: that deviations between the expected and delivered exit fluences are totally caused by errors in the delivered ...


Fabrication And Characterization Of Thinner Solid-State Nanopores, Denis Forbi Tita 2012 University of Arkansas, Fayetteville

Fabrication And Characterization Of Thinner Solid-State Nanopores, Denis Forbi Tita

Theses and Dissertations

Solid State nanopores that are fabricated by the ion beam sculpting process and electron beam drilling have shown great promise as a sensing device for DNA and protein molecules. Even though biological pores such as the alpha-Haemolysin have been in use for quite some time, the use of solid state Nanopores in single biomolecule detection has been on the rise since the mid 1990s. Solid State nanopores have an advantage over biological pores in that they are more robust, stable, and can be sculpted to any desired size for use in translocation experiments. One of the major challenges in Nanopore ...


Validation Of 3'-Deoxy-3'-[18f]-Fluorothymidine Positron Emission Tomography For Image-Guidance In Biologically Adaptive Radiotherapy, Marian Axente 2012 Virginia Commonwealth University

Validation Of 3'-Deoxy-3'-[18f]-Fluorothymidine Positron Emission Tomography For Image-Guidance In Biologically Adaptive Radiotherapy, Marian Axente

Theses and Dissertations

Accelerated tumor cell repopulation during radiation therapy is one of the leading causes for low survival rates of head-and-neck cancer patients. The therapeutic effectiveness of radiotherapy could be improved by selectively targeting proliferating tumor subvolumes with higher doses of radiation. Positron emission tomography (PET) imaging with 3´-deoxy-3´-[18F]-fluorothymidine (FLT) has shown great potential as a non-invasive approach to characterizing the proliferation status of tumors. This thesis focuses on histopathological validation of FLT PET imaging specifically for image-guidance applications in biologically adaptive radiotherapy. The lack of experimental data supporting the use of FLT PET imaging for radiotherapy guidance is ...


Designing An Information-Experience Using Creativity Science & Tools, Stephanie Belhomme 2012 International Center for Studies in Creativity

Designing An Information-Experience Using Creativity Science & Tools, Stephanie Belhomme

Stephanie Belhomme

An “information-experience” encapsulated by a technological/digital audio-visual tool presents data and potentially meaningful information to prompt actionable knowledge concerning: “unspoken creative process elements;” their profound impacts on both how well our “physiology of creativity” functions but also; how well foundational creative thinking and behavioral prerequisites (energy, motivation, imagination, and ownership) are leveraged.

The product: 1) introduces the user to one component of the CPS (Creative Problem Solving) Facilitation Process - Exploring the Challenge; 2) features a content specific component which prompts exploration of the many correlations between societal, organizational / community, human physiological / behavioral data, and the direct relationships of these ...


Characterization Of A Small Animal Spect Platform For Use In Preclinical Translational Research, Dustin Ryan Osborne 2011 University of Tennessee, Knoxville

Characterization Of A Small Animal Spect Platform For Use In Preclinical Translational Research, Dustin Ryan Osborne

Doctoral Dissertations

Imaging Iodine-125 requires an increased focus on developing an understanding of how fundamental processes used by imaging systems work to provide quantitative output for the imaging system. Isotopes like I-125 pose specific imaging problems that are a result of low energy emissions as well as how closely spaced those emissions are in the spectrum. This work seeks to characterize the performance of a small animal SPECT-CT imaging system with respect to imaging I-125 for use in a preclinical translational research environment and to understand how the performance of this system relates to critical applications such as attenuation and scatter correction ...


A Quantitative Method For Reproducible Ionization Chamber Alignment To A Water Surface For External Beam Radiation Therapy Depth Dose Measurements, James Ververs 2011 Virginia Commonwealth University

A Quantitative Method For Reproducible Ionization Chamber Alignment To A Water Surface For External Beam Radiation Therapy Depth Dose Measurements, James Ververs

Theses and Dissertations

Ionization chambers (ICs) are the most commonly used detectors for radiation therapy dose measurements. Typical IC measurements use cylindrical ICs in a water phantom and therefore require initial IC alignment to the water surface. This alignment has long been ignored and only recently has a qualitative governing recommendation been made. This thesis describes a reproducible methodology for quantitative ionization chamber water surface alignment. Depth-ionization measurements are taken with twenty-eight IC designs under varying conditions including, but not limited to, changes in scan direction, speed, and resolution, radiation beam type, field size, energy, and electron contamination. Measurements are acquired using standard ...


Development Of Dose Conversion Coefficients For Radionuclides Produced In Spallation Neutron Sources, Phillip W. Patton 2011 University of Nevada, Las Vegas

Development Of Dose Conversion Coefficients For Radionuclides Produced In Spallation Neutron Sources, Phillip W. Patton

Transmutation Sciences Physics (TRP)

A research consortium comprised of representatives from several universities and national laboratories will be established as part of this project to generate internal and external dose conversion coefficients for radionuclides produced in spallation neutron sources. Information obtained from this multi-year study will be used to support the siting and licensing of future accelerator-driven nuclear initiatives within the U.S. Department of Energy complex, including the Spallation Neutron Source (SNS) and Accelerator Production of Tritium (APT) projects. Determination of these coefficients will also fill data gaps for several hundred radionuclides that exist in Federal Guidance Report (FGR) No. 11 and in ...


Effective Outreach: Tools Of The Trade For Heading Back-To-School, Florida Covering Kids & Families 2011 mchavez10@gmail.com

Effective Outreach: Tools Of The Trade For Heading Back-To-School, Florida Covering Kids & Families

Florida Covering Kids & Families

Effective marketing and education through outreach strategies are critical to guarantee uninsured but eligible children enroll and retain coverage in Children’s Health Insurance Programs, such as Florida KidCare. The implementation of effective outreach can eliminate enrollment barriers. The authors cite that the tools for innovative practices for effective outreach strategies include: personal contact and involvement with an outreach coalition.


Statistical Image Reconstruction For Quantitative Computed Tomography, Joshua Evans 2011 Virginia Commonwealth University

Statistical Image Reconstruction For Quantitative Computed Tomography, Joshua Evans

Theses and Dissertations

Statistical iterative reconstruction (SIR) algorithms for x-ray computed tomography (CT) have the potential to reconstruct images with less noise and systematic error than the conventional filtered backprojection (FBP) algorithm. More accurate reconstruction algorithms are important for reducing imaging dose and for a wide range of quantitative CT applications. The work presented herein investigates some potential advantages of one such statistically motivated algorithm called Alternating Minimization (AM). A simulation study is used to compare the tradeoff between noise and resolution in images reconstructed with the AM and FBP algorithms. The AM algorithm is employed with an edge-preserving penalty function, which is ...


Radiation Therapy Treatment Plan Optimization Accounting For Random And Systematic Patient Setup Uncertainties, Joseph Moore 2011 Virginia Commonwealth University

Radiation Therapy Treatment Plan Optimization Accounting For Random And Systematic Patient Setup Uncertainties, Joseph Moore

Theses and Dissertations

External-beam radiotherapy is one of the primary methods for treating cancer. Typically a radiotherapy treatment course consists of radiation delivered to the patient in multiple daily treatment fractions over 6-8 weeks. Each fraction requires the patient to be aligned with the image acquired before the treatment course used in treatment planning. Unfortunately, patient alignment is not perfect and results in residual errors in patient setup. The standard technique for dealing with errors in patient setup is to expand the volume of the target by some margin to ensure the target receives the planned dose in the presence of setup errors ...


Characterization Of A Blast Wave Device And Blast Wave Induced Traumatic Brain Injury In A Rat Model By Magnetic Resonance Imaging And Spectroscopy, Frank Corwin 2011 Virginia Commonwealth University

Characterization Of A Blast Wave Device And Blast Wave Induced Traumatic Brain Injury In A Rat Model By Magnetic Resonance Imaging And Spectroscopy, Frank Corwin

Theses and Dissertations

Blast wave induced traumatic brain injury (bTBI) is a modality of injury that has come into prominence at the current time due to the large number of military and civilian personnel who have experienced the localized shock wave produced by explosive devices. The shock wave will travel concentrically outward from the explosive center, being absorbed and transmitted thru soft objects, such as tissue, and reflecting off stationary obstructions. Transmission and absorption in tissues can result in a number of physiological measureable injuries, the most common of which being what is frequently called “blast lung”. Blast lung involves the spalling effect ...


Brachytherapy Seed And Applicator Localization Via Iterative Forward Projection Matching Algorithm Using Digital X-Ray Projections, Damodar Pokhrel 2010 Virginia Commonwealth University

Brachytherapy Seed And Applicator Localization Via Iterative Forward Projection Matching Algorithm Using Digital X-Ray Projections, Damodar Pokhrel

Theses and Dissertations

Interstitial and intracavitary brachytherapy plays an essential role in management of several malignancies. However, the achievable accuracy of brachytherapy treatment for prostate and cervical cancer is limited due to the lack of intraoperative planning and adaptive replanning. A major problem in implementing TRUS-based intraoperative planning is an inability of TRUS to accurately localize individual seed poses (positions and orientations) relative to the prostate volume during or after the implantation. For the locally advanced cervical cancer patient, manual drawing of the source positions on orthogonal films can not localize the full 3D intracavitary brachytherapy (ICB) applicator geometry. A new iterative forward ...


Adaptive Radiation Therapy Of Prostate Cancer, Ning Wen 2010 Wayne State University

Adaptive Radiation Therapy Of Prostate Cancer, Ning Wen

Wayne State University Dissertations

ART is a close-loop feedback algorithm which evaluates the organ deformation and motion right before the treatment and takes into account dose delivery variation daily to compensate for the difference between planned and delivered dose. It also has potential to allow further dose escalation and margin reduction to improve the clinical outcome. This retrospective study evaluated ART for prostate cancer treatment and radiobiological consequences. An IRB approved protocol has been used to evaluate actual dose delivery of patients with prostate cancer undergoing treatment with daily CBCT.

The dose from CBCT was measured in phantom using TLD and ion chamber techniques ...


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