Other Analytical, Diagnostic and Therapeutic Techniques and Equipment Commons^™

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 …

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 …

Quantitative Dwi As An Early Imaging Biomarker Of The Response To Chemoradiation In Esophageal Cancer, Benjamin C. Musall

Dissertations & Theses (Open Access)

For patients diagnosed with stages IIa-IIb esophageal cancer, the current standard of care treatment is tri-modality therapy (TMT), where neoadjuvant chemoradiation (nCRT) is followed by surgical resection. Histopathology of resected tumors reveals that pathological complete response (pCR) is achieved in 20-30% of patients through nCRT alone. Because of the high mortality and morbidity associated with esophagectomy, it may be advantageous for patients exhibiting pCR from nCRT alone to be placed under observation rather than completing their TMT. Therefore, a method for predicting response at an early time-point during nCRT is highly desirable. Conventional methods such as endoscopic ultrasound, re-biopsy, and …

Correlation Matrix Analysis Identifies Gene Signatures Of Immune Cell Subsets And Their Interactions In Follicular Lymphoma, Jason R. Westin

Dissertations & Theses (Open Access)

There are important but ill-defined interactions between benign immune cell subsets and neoplastic B cells within follicular lymphoma (FL). Using the novel technique of correlation matrix analysis (CMA) of publicly available FL whole-tumor gene expression profiling (GEP) data, we have identified signatures of immune cell subsets. Overall survival correlated most highly with a model using signatures of macrophages, T cells, and stroma, which was able to add significantly to existing clinical prognostic tools. From our own data of a cohort of 43 FL tumors sorted into B-cell and non-B cell (NB) fractions for GEP, CMA of the tumor infiltrating NB …

Utilizing Haplotypes For Sensitive Snp Array-Based Discovery Of Somatic Chromosomal Mutations, Selina M. Vattathil

Dissertations & Theses (Open Access)

Somatic copy-number (CN) gains and losses and copy-neutral loss of heterozygosity (CNLOH) frequently occur in tumors and play a major role in the progression of disease by altering gene dosage and unmasking deleterious recessive variants. Characterizing these mutations in an individual tumor sample is therefore critical for research on the relationship of specific mutations to disease outcome and for clinical decision-making based on mutations with known impact. A pervasive hindrance to sensitive detection of these mutations is genetic heterogeneity and high levels of contaminating normal cells in tumor samples, which limit the fraction of cells carrying informative mutations. The method …

Design, Synthesis And Development Of Transporter Targeting Agents For Image-Guided Therapy And Drug Delivery, Ning Tsao

Dissertations & Theses (Open Access)

The purpose of this study was to design, synthesize and develop novel transporter targeting agents for image-guided therapy and drug delivery. Two novel agents, N4-guanine (N4amG) and glycopeptide (GP) were synthesized for tumor cell proliferation assessment and cancer theranostic platform, respectively. N4amG and GP were synthesized and radiolabeled with ^99mTc and ⁶⁸Ga. The chemical and radiochemical purities as well as radiochemical stabilities of radiolabeled N4amG and GP were tested. In vitro stability assessment showed both ^99mTc-N4amG and ^99mTc-GP were stable up to 6 hours, whereas ⁶⁸Ga-GP was stable up to 2 hours. Cell culture studies …

Annexin A5-Conjugated Polymeric Micelles For Dual Spect And Optical Detection Of Apoptosis, Rui Zhang

Dissertations & Theses (Open Access)

Apoptosis, a form of programmed cell death, is critical to homoeostasis, normal development, and physiology. Dysregulation of apoptosis can lead to the accumulation of unwanted cells, such as occurs in cancer, and the removal of needed cells or disorders of normal tissues, such as heart, neurodegenerative, and autoimmune diseases. Noninvasive detection of apoptosis may play an important role in the evaluation of disease states and response to therapeutic intervention for a variety of diseases. It is desirable to have an imaging method to accurately detect and monitor this process in patients. In this study, we developed annexin A5-conjugated polymeric micellar …

The Development And Implementation Of An Anthropomorphic Head Phantom For The Assessment Of Proton Therapy Treatment Procedures, Paige A. Summers

Dissertations & Theses (Open Access)

Proton therapy has become an increasingly more common method of radiation therapy, with the dose sparing to distal tissue making it an appealing option, particularly for treatment of brain tumors. This study sought to develop a head phantom for the Radiological Physics Center (RPC), the first to be used for credentialing of institutions wishing to participate in clinical trials involving brain tumor treatment of proton therapy. It was hypothesized that a head phantom could be created for the evaluation of proton therapy treatment procedures (treatment simulation, planning, and delivery) to assure agreement between the measured dose and calculated dose within …

Evaluation Of Intensity Modulated Radiation Therapy (Imrt) Delivery Error Due To Imrt Treatment Plan Complexity And Improperly Matched Dosimetry Data, Jacqueline R. Tonigan

Dissertations & Theses (Open Access)

Intensity modulated radiation therapy (IMRT) is a technique that delivers a highly conformal dose distribution to a target volume while attempting to maximally spare the surrounding normal tissues. IMRT is a common treatment modality used for treating head and neck (H&N) cancers, and the presence of many critical structures in this region requires accurate treatment delivery. The Radiological Physics Center (RPC) acts as both a remote and on-site quality assurance agency that credentials institutions participating in clinical trials. To date, about 30% of all IMRT participants have failed the RPC’s remote audit using the IMRT H&N phantom. The purpose …

The Effect Of Shoulder Variation On Imrt And Smartarc For Head And Neck Cancer, Emily H. Neubauer

Dissertations & Theses (Open Access)

Purpose: First, to determine an average and maximum displacement of the shoulder relative to isocenter over the course of treatment. Second, to establish the dosimetric effect of shoulder displacements relative to correct isocenter alignment on the dose delivered to the target and the surrounding structures for head and neck cancer patients.

Method and Materials: The frequency of shoulder shifts of various magnitudes relative to isocenter was assessed for 4 patients using image registration software. The location of the center of the right and left humeral head relative to isocenter (usually C2) was found daily from CT on rails scans, and …

Clinical Impact Of Couch Top And Rails On Imrt And Arc Therapy, Kiley B. Pulliam

Dissertations & Theses (Open Access)

Purpose: To evaluate the clinical impact of the Varian Exact Couch on dose and volume coverage to targets and critical structures and tumor control probability (TCP) for 6-MV IMRT and Arc Therapy.

Methods: Five clinical prostate patients were planned with both, 6-MV 8-field IMRT and 6-MV 2-field RapidArc using the Eclipse treatment planning system (TPS). These plans neglected treatment couch attenuation, as is standard clinical practice. Dose distributions were then recalculated in Eclipse with the inclusion of the Varian Exact Couch (imaging couch top) and the rails in varying configurations. The changes in dose and coverage were evaluated using the …

Commissioning An Anthropomorphic Spine And Lung Phantom For Remote Dose Verification Of Institutions Participating In Rtog 0631, Douglas F. Caruthers

Dissertations & Theses (Open Access)

The RPC developed a new phantom to ensure comparable and consistent radiation administration in spinal radiosurgery clinical trials. This study assessed the phantom’s dosimetric and anatomic utility. The ‘spine phantom’ is a water filled thorax with anatomy encountered in spinal radiosurgery: target volume, vertebral column, spinal canal, esophagus, heart, and lungs. The dose to the target volume was measured with axial and sagittal planes of radiochromic film and thermoluminescent dosimeters (TLD). The dose distributions were measured with the radiochromic film calibrated to the absolute dose measured by the TLD. Four irradiations were administered: a four angle box plan, a seven …