Radiology Commons^™

Improving Dose-Response Correlations For Locally Advanced Nsclc Patients Treated With Imrt Or Pspt, Yulun He

Dissertations & Theses (Open Access)

The standard of care for locally advanced non-small cell lung cancer (NSCLC) is concurrent chemo-radiotherapy. Despite recent advancements in radiation delivery methods, the median survival time of NSCLC patients remains below 28 months. Higher tumor dose has been found to increase survival but also a higher rate of radiation pneumonitis (RP) that affects breathing capability. In fear of such toxicity, less-aggressive treatment plans are often clinically preferred, leading to metastasis and recurrence. Therefore, accurate RP prediction is crucial to ensure tumor coverage to improve treatment outcome. Current models have associated RP with increased dose but with limited accuracy as they …

Absolute Quantification Of Tc-99m Activity Distributions Using A Planar Molecular Breast Imaging Commercial System, Benjamin P. Lopez

Dissertations & Theses (Open Access)

Molecular breast imaging (MBI) uses two dedicated-breast semiconductor detectors to visualize the preferential uptake of technetium-99m-sestamibi (^99mTc-sestamibi) by breast cancer cells relative to surrounding benign breast tissues. Clinically, MBI is used primarily as a supplementary tool to standard-of-care mammography because of its improved detection of breast cancers, especially in women with mammographically-dense breasts. Because of a lack of image corrections, MBI applications are currently limited to qualitative evaluations of relative pixel intensities between image regions with suspected lesions and normal tissue.

The objective of this dissertation was to use Monte Carlo simulations to better characterize the MBI imaging …

Development Of Advanced Mr-Guided Adaptive Radiation Therapy Methods For Head & Neck Cancers On The 1.5t Mr-Linac, Brigid Mcdonald

Dissertations & Theses (Open Access)

The 1.5T hybrid MRI/linear accelerator (MR-linac) has recently been introduced into clinical practice and used for the treatment of head and neck cancers (HNC). This device enables on-line adaptive radiation therapy (ART) based on anatomical changes throughout treatment and variations in patient position. This novel technology also has the potential for advanced ART strategies such as dose-optimized ART, in which the treatment plan is optimized based on the accumulated dose over previous fractions, or biological image-guided ART, in which the plan is adapted based on individual tumor response as measured through quantitative imaging techniques such as diffusion-weighted imaging (DWI). The …

Hepatocellular Carcinoma Image-Guided Intervention: Quantitative Characterization Of Reagents For Thermochemical Ablation, Emily A. Thompson

Dissertations & Theses (Open Access)

Thermochemical ablation (TCA) is a minimally invasive therapy under development for hepatocellular carcinoma, a leading cause of cancer death worldwide. TCA utilizes acid-base chemistry delivered simultaneously to induce local ablation when administered. When delivered via a mixing catheter placed directly into the tumor, acid (e.g., AcOH) and base (e.g., NaOH) react to completion at the catheter tip, producing the acetate salt, water, and releasing heat (Δ>50°C) in sufficient quantities to induce lethal osmotic and thermal stress in tumor cells. However, these two reagents are not distinguishable from tissues with noninvasive imaging modalities, which makes monitoring the delivery of TCA …

Integration Of Biomedical Imaging And Translational Approaches For Management Of Head And Neck Cancer, Abdallah Mohamed, Abdallah Mohamed

Dissertations & Theses (Open Access)

The aim of the clinical component of this work was to determine whether the currently available clinical imaging tools can be integrated with radiotherapy (RT) platforms for monitoring and adaptation of radiation dose, prediction of tumor response and disease outcomes, and characterization of patterns of failure and normal tissue toxicity in head and neck cancer (HNC) patients with potentially curable tumors. In Aim 1, we showed that the currently available clinical imaging modalities can be successfully used to adapt RT dose based-on dynamic tumor response, predict oncologic disease outcomes, characterize RT-induced toxicity, and identify the patterns of disease failure. We …

Quantitative Magnetic Resonance Imaging For The Early Prediction Of Treatment Response In Triple Negative Breast Cancer, Benjamin C. Musall

Dissertations & Theses (Open Access)

Triple Negative Breast Cancer (TNBC) is an aggressive subtype of breast cancer which lacks upregulated hormone receptors. Because of this, it is not vulnerable to clinically available targeted therapies. When treated with standard of care neoadjuvant systemic therapy (NAST), TNBC only shows approximately a 40% rate of pathologic complete response (pCR). A biomarker which could predict TNBC response to NAST early during treatment would be useful, as it would allow for non-responders to be triaged to alternative therapies and potentially allow for the treatment of responders to be de-escalated.

Quantitative Magnetic Resonance Imaging (MRI) may be used to probe and …

Development Of A Ct Metal Artifact Management Algorithm For Proton Therapy Planning (Ampp) For Head And Neck Cancer Patients, Daniela Branco

Dissertations & Theses (Open Access)

Purpose: Dental amalgams (high Z materials) are common sources of artifacts in Head and Neck (HN) images. Commercial artifact reduction techniques have been offered, but many are impractical, produce inaccurate CT images or are not clinically available, thus not widely implemented. The goal of this work is to use CT gantry tilts to develop and evaluate a stereoscopic HN metal artifact management algorithm and investigate its improvement in proton treatment planning.

Methods: The in-house CT metal artifact management method for proton planning (AMPP) uses two angled CT scans to generate a single image set with no metal artifacts posterior …

Investigating The Metabolic Progression Of Glioblastoma With Hyperpolarized Magnetic Resonance, Travis Salzillo

Dissertations & Theses (Open Access)

Rapid diagnosis and therapeutic monitoring of aggressive diseases such as glioblastoma (GBM) can improve patient survival by providing physicians the time to optimally deliver treatment. This includes early in development, while the tumor is still manageable, or following initial therapy, when alternative treatments should be considered. The main goal of this project was to determine whether metabolic imaging with hyperpolarized magnetic resonance spectroscopy (MRS) could detect changes in tumor progression more rapidly than conventional anatomic magnetic resonance imaging (MRI) in patient-derived GBM murine models. To comprehensively capture the dynamic nature of cancer metabolism, in vivo pyruvate-to-lactate conversion with hyperpolarized MRI, …

Development Of 3d-Printed Patient Specific Bolus For Clinical Use In Total Scalp Irradiation, Garrett Baltz

Dissertations & Theses (Open Access)

Total scalp irradiation (TSI) is a specialized radiation therapy technique that aims to deliver a uniform dose to the entire scalp. Original electron-based TSI techniques had limited homogeneity due to hot and cold spots created at field junctions due to the multiple matched fields that were required to treat the entire scalp. The transition to photon volumetric-modulated arc therapy based TSI techniques has improved homogeneity, to the point where non-conformal bolus is now a limiting factor. Bolus is required to build-up full dose to the scalp surface in total scalp irradiation. Creating bolus that is conformal to the scalp is …

Scanned Ion Beam Therapy For Thoracic Tumors, John Gordon Eley

Dissertations & Theses (Open Access)

Although frequently cured of Hodgkin lymphoma, adolescents and young adults can develop radiation induced second cancers. These patients could potentially benefit from scanned ion radiotherapy yet likely would require motion mitigation strategies. In theory, four-dimensional (4D) optimization of ion beam fields for individual motion states of respiration can enable superior sparing of healthy tissue near moving targets, compared to other motion mitigation strategies. Furthermore, carbon-ion therapy can sometimes provide greater relative biological effectiveness (RBE) for cell sterilization in a target but nearly equivalent RBE in tissue upstream of the target, compared to proton therapy. Thus, we expected that for some …

Novel Amino Acid Transporter-Targeted Radiotracers For Breast Cancer Imaging, Fanlin Kong

Dissertations & Theses (Open Access)

Breast cancer is the most common malignancy among women in the world. Its 5-year survival rate ranges from 23.4% in patients with stage IV to 98% in stage I disease, highlighting the importance of early detection and diagnosis. ¹⁸F-2-Fluoro-2-deoxy-glucose (¹⁸F-FDG), using positron emission tomography (PET), is the most common functional imaging tool for breast cancer diagnosis currently. Unfortunately, ¹⁸F-FDG-PET has several limitations such as poorly differentiating tumor tissues from inflammatory and normal brain tissues. Therefore, ¹⁸F-labeled amino acid-based radiotracers have been reported as an alternative, which is based on the fact that tumor cells uptake …

Thoracic Radiotherapy Treatment Planning With Cine Pet/Ct, Adam C. Riegel

Dissertations & Theses (Open Access)

Purpose: Respiratory motion causes substantial uncertainty in radiotherapy treatment planning. Four-dimensional computed tomography (4D-CT) is a useful tool to image tumor motion during normal respiration. Treatment margins can be reduced by targeting the motion path of the tumor. The expense and complexity of 4D-CT, however, may be cost-prohibitive at some facilities. We developed an image processing technique to produce images from cine CT that contain significant motion information without 4D-CT. The purpose of this work was to compare cine CT and 4D-CT for the purposes of target delineation and dose calculation, and to explore the role of PET in target …