Physics Commons^™

Multi-Modality Automatic Lung Tumor Segmentation Method Using Deep Learning And Radiomics, Siqiu Wang

Theses and Dissertations

Delineation of the tumor volume is the initial and fundamental step in the radiotherapy planning process. The current clinical practice of manual delineation is time-consuming and suffers from observer variability. This work seeks to develop an effective automatic framework to produce clinically usable lung tumor segmentations. First, to facilitate the development and validation of our methodology, an expansive database of planning CTs, diagnostic PETs, and manual tumor segmentations was curated, and an image registration and preprocessing pipeline was established. Then a deep learning neural network was constructed and optimized to utilize dual-modality PET and CT images for lung tumor segmentation. …

Direction Modulated Brachytherapy For The Treatment Of Cervical Cancer, Dylan Richeson

Theses and Dissertations

Purpose: To evaluate and compare the performance of 9 experimental DMBT tandem models of varying physical dimensions in relation to 24 previously planned HDR cervical cancer treatment plans from multiple institutions that used conventional tandem and rings or ovoid applicators.

Methods and Materials: The DMBT tandem is designed to be used concurrently with IGABT and is made from an MRI-compatible tungsten-alloy rod with 6 channels grooved out of its periphery. 9 experimental DMBT tandem prototypes were provided. Each of the models was of equal lengths but varied in thickness, channel diameter size, and circle channel diameter size. Replanning …

Periodic Trends In The Infrared And Optical Absorption Spectra Of Metal Chalcogenide Clusters, Alain Ward

Theses and Dissertations

We have investigated the Optical absorption, Infrared spectra, Binding Energies, and various other cluster properties to determine the existence of periodic trend for Transition Metal Chalcogenide Clusters ligated with CO ligands. We were motivated to answer the question of whether periodic behavior can be observed in properties of octahedral metal-chalcogenide clusters. We have used the Amsterdam Density Functional code to calculate the electronic structure of Transition Metal Chalcogenide Clusters using gradient-corrected density functional theory. We determined the existence of several periodic trends in properties of octahedral Transition Metal Chalcogenide Clusters TM₆Se₈(CO)₆. To investigate these …

Development Of Novel Intracavitary Intensity Modulated Brachytherapy Applicators For Optimizing The Target Coverage In Gynecologic Malignancies, Monte Carlo Simulation Dosimetry, Moeen Meftahi

Theses and Dissertations

Gynecologic brachytherapy (GYN-BT) is essential for treating cervical and endometrial cancers, the most prevalent female reproductive cancers. This technique enables high radiation doses to a target with rapid dose fall-off to protect adjacent healthy organs. This dissertation aims to address some of the limitations of intracavitary GYN-BT using an intensity modulated brachytherapy (IMBT) technique and Monte Carlo (MC) simulations.

First, a novel non-invasive shielded vaginal cylinder (VC) applicator was designed to provide optimized radiation coverage for the target volume at vaginal apex, site of most recurrences without BT, for endometrial cancer BT. Physical limitations of current applicators and their resulting …