Medicine and Health Sciences Commons^™

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 …

Investigation Of Respiratory Motion Management Techniques For Proton And Photon Radiotherapy Of Lung Cancer, Jason E. Matney

Dissertations & Theses (Open Access)

Protons as a source of therapeutic radiation can provide a substantial improvement over dose distributions that can be achieved with conventional sources of radiation such as high-energy photons. However, respiratory motion can significantly impact the delivered proton and photon dose distributions during lung cancer radiotherapy. The goals of this dissertation research were to evaluate the impact of respiratory motion and to estimate the benefit of respiratory gating for passively scattered proton therapy (PSPT) and intensity modulated photon therapy (IMRT).

The first aim of this project was to determine the impact of respiratory motion in PSPT and IMRT. Four dimensional dose …

Evaluation Of Presage® Dosimeters For Brachytherapy Sources And The 3d Dosimetry And Characterization Of The New Agx100 125i Seed Model, Olivia Huang

Dissertations & Theses (Open Access)

With continuous new improvements in brachytherapy source designs and techniques, method of 3D dosimetry for treatment dose verifications would better ensure accurate patient radiotherapy treatment. This study was aimed to first evaluate the 3D dose distributions of the low-dose rate (LDR) Amersham 6711 Oncoseed^TM using PRESAGE^® dosimeters to establish PRESAGE^® as a suitable brachytherapy dosimeter. The new AgX100 ¹²⁵I seed model (Theragenics Corporation) was then characterized using PRESAGE^® following the TG-43 protocol.

PRESAGE^® dosimeters are solid, polyurethane-based, 3D dosimeters doped with radiochromic leuco dyes that produce a linear optical density response to radiation dose. …

Improving Cervical Cancer Nodal Boost Radiation Therapy By Quantifying Uncertainties And Exploring Advanced Radiation Therapy Modalities, Zhiqian Yu

Dissertations & Theses (Open Access)

Radiation therapy for patients with intact cervical cancer is frequently delivered using primary external beam radiation therapy (EBRT) followed by two fractions of intracavitary brachytherapy (ICBT). Although the tumor is the primary radiation target, controlling microscopic disease in the lymph nodes is just as critical to patient treatment outcome. In patients where gross lymphadenopathy is discovered, an extra EBRT boost course is delivered between the two ICBT fractions. Since the nodal boost is an addendum to primary EBRT and ICBT, the prescription and delivery must be performed considering previously delivered dose. This project aims to address the major issues of …