Radiation Medicine Commons^™

Atr-Mediated Cd47 And Pd-L1 Upregulation Restricts Radiotherapy-Induced Immune Priming And Abscopal Responses In Colorectal Cancer, Cheng-En Hsieh, Cheng-En Hsieh

Dissertations & Theses (Open Access)

Radiotherapy of colorectal cancer (CRC) can prime adaptive immunity against tumor-associated antigen (TAA)-expressing CRC cells systemically. However, incidences of abscopal tumor remission are extremely rare, and the post-irradiation immune escape mechanisms in CRC remain elusive. We report that CRC cells utilize a common DNA repair signaling pathway — ATR/Chk1/STAT3 — to upregulate both CD47 and PD-L1 in response to radiotherapy, which through engagement of SIRPα and PD-1 suppresses the capacity of antigen-presenting cells to phagocytose them thereby preventing TAA cross-presentation and innate immune activation. This post-irradiation CD47 and PD-L1 upregulation can be observed across various human solid tumor cells. Concordantly, …

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 …

A Method For Predicting Dose Changes For Hn Treatment Using Surface Imaging, Sarah E. Holler

Theses and Dissertations

Head and neck cancer is commonly treated with a six- to seven-week course of radiotherapy, during which a patient’s anatomy may change substantially, due to target reduction or weight loss. Anatomical changes lead to reduction in treatment quality due to decreased setup reproducibility and altered dose deposition compared to the original plan. Few clinics have developed a standard method for triggering resimulation and replan due to anatomic changes. This work investigates a new method for determining when to resimulate and replan HNC patients by utilizing their topographic anatomical changes to predict differences in planned versus delivered dose distributions. The first …

Automation Of Radiation Treatment Planning For Cervical Cancer, Dong Joo Rhee

Dissertations & Theses (Open Access)

Cervical cancer is one of the most common cancer in low- and middle-income countries (LMICs). The mortality rate can be reduced if radiation treatment becomes widely available. However, due to the lack of radiation treatment facilities and human resources, many cervical cancer patients in Africa are not able to receive timely treatments or advanced therapies. To increase the availability of radiation treatment in low-and middle-income countries (LMICs) including African countries, many attempts have been made to reduce the cost of medical linear accelerators. However, increasing the number of treatment machines would not instantly resolve the issues, as there would be …

Analytical Setup Margin For Spinal Sbrt Based On Measured Errors, Audrey Copeland

LSU Master's Theses

Purpose: No consensus currently exists in the radiotherapy community about the correct margin size to use for spinal SBRT. Margins have been proposed to account for various errors individually, but not with all errors combined to result in a single margin value. The purpose of this work was to determine a setup margin for spinal SBRT based on known and measurable errors during radiotherapy to achieve at least 90% coverage of the clinical target volume (CTV) with the prescription dose for at least 90% of patients and not exceed a 30 Gy point dose or 23 Gy to 10% of …

Development Of Automated Radiotherapy Treatment Planning For Cervical And Breast Cancer For Resource-Constrained Clinics, Kelly Kisling

Dissertations & Theses (Open Access)

Globally, cancer rates are on the rise, especially in low- and middle-income countries (LMICs). However, many of these countries lack access to radiotherapy, which is due in part to a substantial shortage of the staff necessary to deliver safe and effective radiotherapy. This staff shortage could be mitigated by the automation of the radiation treatment planning process. To this end, we developed automated planning for cervical and postmastectomy breast cancer radiotherapy, the two most common types of cancer in women in many LMICs.

For radiotherapy of cervical cancer in resource-constrained clinics, the recommended treatment technique is a four-field box. We …