Digital Commons Network^™

Growing Need For A Standardized Response To Radiopharmaceutical Extravasations, Michael Richard Drelich

All ETDs from UAB

Extravasations are medical occurrences where an injected or infused pharmaceutical is unintentionally deposited into the soft tissue near the injection site, rather than into the bloodstream. With radiopharmaceuticals, extravasations can result in potentially large radiation doses to skin and tissue. The current rate of extravasations in clinical settings is estimated to be between 3-23%. In the interest of patient safety, a clearer understanding of the dosimetry and differences in extravasation scenarios to simplify dose estimation is needed. Similarly, the NRC is considering modifying regulations to include extravasations as reportable medical events rather than to continue considering them as patient interventions. …

Interfraction Variability Of Breathing Amplitude Of Patients Undergoing Sbrt Lung Treatment And The Potential Impact On Dosimetry, Christian Padilla Gallegos

Culminating Experience Projects

Abstract

Introduction

The study investigated the consistency of free breathing planning margins for fractionated SBRT treatment in the lung. The study compared breathing motion from the average CT (AVE CT) scan to the Cone Beam Computed Tomography (CBCT) from each treatment session. Various breathing techniques were also discussed, including deep inspiration breath hold (DIBH), gated breathing, abdominal compression (AC), and free breathing (FB). Free-breathing may lead to overdosing on surrounding healthy tissue if significant changes in breathing amplitude occur. Abdominal compression or breath hold may reduce abnormal breathing movement if erratic breathing occurs. The study's aim was to ensure the …

Quantitative Benefits Of Reducing The Inferior Border Of Right-Sided Free Breathing Intact Breast Treatment Plans Regarding Liver Dose, Shelby Handshue

Culminating Experience Projects

Introduction

Breast cancer is a prevalent disease in the United States, affecting approximately one in eight women during their lifetime (Leaver & Washington, 2010). Advancements in medical treatments have evolved from mastectomy to a multidisciplinary approach. Radiation therapy plays a crucial role in preventing local recurrence after breast conserving surgery. Traditionally, whole breast irradiation has been administered over 25-28 fractions to a total dose of 45-50 Gray (Gy), followed by a boost of 5-8 fractions to the tumor bed. In recent times, hypofractionation, which involves a shorter treatment schedule of 15-16 fractions to a total dose of 42.5 Gy, followed …

A Dosimetric Comparison Of Coplanar And Non-Coplanar Beam Arrangement For Apbi Treatment Techniques, Reuben Granger

Culminating Experience Projects

Abstract

Introduction

Breast cancer is a prevalent malignancy among women in the United States, necessitating a variety of treatment strategies. Accelerated Partial Breast Irradiation (aPBI) has emerged as an effective treatment technique for early-stage breast cancer, offering reduced treatment duration and potential benefits in terms of cosmesis and patient convenience. One of the critical factors influencing the success of APBI is the choice of beam arrangement during radiation delivery. This research paper presents a dosimetric comparison of coplanar and non-coplanar beam arrangements for APBI treatment techniques.

Methods

The study includes 15 patients with left-sided breast cancer. The patients underwent two …

Determination Of Optimal Block Margins For Stereotactic Body Radiotherapy (Sbrt) Of Island-Type Lung Lesions With Dynamic Conformal Arc Therapy (Dcat) And Acuros Xb., George C. Kozan

Culminating Experience Projects

Abstract

Introduction

Stereotactic Body Radiotherapy (SBRT) has become a highly effective treatment option for patients with island-type lung lesions, offering precise targeting and minimal damage to the surrounding healthy tissue. Acuros XB dose calculation algorithm has shown promising results in delivering high radiation doses with improved accuracy. Dynamic Conformal Arc Therapy (DCAT) has shown promise with lesions that are uniform and non-concave. Combining Acuros and DCAT has potential to help when planning Island-type lung SBRT. However, determining the optimal block margins for this treatment approach remains a critical challenge to find a balance between tumor coverage and sparing of critical …

Preliminary Characterisation Of An Active Cmos Pad Detector For Dosimetry In Hdr Brachytherapy, Thi Ngoc Hang Bui

University of Wollongong Thesis Collection 2017+

This thesis aims to characterise the accuracy of a new active CMOS pad detector for dosimetry in HDR Brachytherapy. A 1x1x1 mm³ detector is doped with high resistivity n-type silicon, thickness of 100 μm (Wafer10) and 48 μm (Wafer20) epitaxial substrate and built in standard CMOS along with a transimpedance amplifier. This work investigates and examine this detector’s sensitivity and signal to noise ratio in air for use in High Dose Rate Brachytherapy (HDR BT) dosimetry.

To understand operational characteristics of the detector, a current-voltage (I-V) characteristic curve was created, and the depletion voltage of the junction observed by …

Toward A Pixelated Solid State Detector For In-Vivo Dosimetry In Radiotherapy, Owen John Brace

University of Wollongong Thesis Collection 2017+

A large area pixelated silicon array detector named \MP987" has been developed for in-vivo dosimetry. The detector was developed to overcome the non-water equivalent response of EPID (Electronic Portal Imaging Device) dosimetry systems, due to the shortfalls of the extensive corrections required. The detector, readout system and software have all been custom designed and operate independently from the linac. The MP987 array is secured directly above the EPID, to be used in combination with the 6 MV imaging system.

During the course of this thesis many aspects of in-vivo dosimetry were looked at, including: electrical and dosimetric characteristics of silicon …

A Quantitative Investigation Of Treating Lung Tumors With Dynamic Conformal Arcs Vs. Vmat For Lung Sbrt Plans, Shawn Loutos

Culminating Experience Projects

Introduction

This study aims to investigate the comparisons in dynamic conformal arc, VMAT (no ASC), forced MU limitations (ASC), or a 50/50 hybrid arc (ASC) in how they can improve a lung SBRT case where the tumor is abutting a dose critical structure. The goal of this research is to investigate multiple treatment techniques in an attempt to increase the dose constraint pass rate. The variables in comparison are how well different plan iterations can successfully meet constraints as well as pass a 0.5 modulation complexity score (MCS).

Methods

10 previously treated patients were used in this study who exhibited …

Effects Of Ezfluence Planning Software On Dosimetric Parameter Compliance For Early-Stage Breast Cancer, Jackie Loomis

Culminating Experience Projects

Each year over 2 million women are given a breast cancer diagnosis and over half a million women succumb to the disease yearly. As technology advances in the world of radiation oncology, automated planning softwares, such as Radformation’s EZFluence, are being utilized to streamline the treatment planning process. This study was designed to investigate whether the automated plans are dosimetrically equivalent to traditionally planned 3D field in field tangential plans. Is there a disadvantage to using these automated softwares? Three different dosimetrists with varying backgrounds replanned 27 previously treated breast cancer patients and an assortment of comparisons were ran between …

Using Radformation Ezfluence Software To Simplify Three Field Breast Radiation Therapy Planning Compared To Field-In-Field Technique, Brianna L. Woodburn

Culminating Experience Projects

Purpose: To evaluate time savings, efficiency, and accuracy of an automated planning software.

Methods: 10 previously treated breast cancer patients with supraclavicular involvement were retrospectively planned using a monosiocentric field-in-field technique by both an automated treatment planning software and a human planner. Time spent on planning was recorded and after plans were generated, dose constraints and target coverage were measured to evaluate overall plan quality.

Results: Time spent for planning was significantly decreased when using a FIF plan generated by the automated planning software. CTV target coverage for both the breast and supraclavicular volumes and dose to OARs for both …

Optical Dosimeters For Radiotherapy With Mri-Linacs, Levi J. Madden

University of Wollongong Thesis Collection 2017+

In modern radiation therapy, treatment delivery techniques are getting increasingly complex to optimise patient outcomes. In modern radiation therapy clinics, there are conditions where accurate dosimetry is challenging, yet essential to ensure that optimal treatments are being delivered. These challenging dosimetry conditions require specialised dosimeters with a set of dosimetric qualities that allow them to remain accurate in such conditions. Fibre-coupled luminescent dosimeters possess a wealth of desirable qualities that make them advantageous for a wide range of dosimetry conditions. Due to their all-optical composition (i.e. no electronics or wires attached to the sensitive volume) and their typically compact sensitive …

Optimisation Of The End-To-End Phantom For Real-Time High Dose Rate Prostate Brachytherapy Verification, Nicholas Ambrosi

University of Wollongong Thesis Collection 2017+

High dose rate (HDR) brachytherapy is a form of close range radiotherapy whereby dose is delivered by means of an internal radiation source. By doing so, a high level of dose con-formity and accuracy can be achieved. However, due to the high source activity coupled with the close proximity of radio-sensitive organs such as the rectum, bladder and urethra, there exists the potential of incorrect dose delivery; the irradiation of these organs may con-sequently lead to post-treatment complications. As a result, the need for accurate forms of quality assurance methodology which can verify different aspects of the treatment delivery is …

Analyses For The Production And Dosimetry Of Adding Uranium-232 As A Tracer To The Uranium Fuel Cycle, Joshua H. Rhodes

Doctoral Dissertations

This dissertation is an examination of the use of uranium-232 as a tracer in nuclear fuel. Decay daughters from ²³²U, particularly thallium-208, produce high energy gamma rays that, when added to uranium, may increase detectability in case of theft or diversion, but are also hazardous in high quantities. Previous studies of the ²³²U decay chain are examined. This work will go in to a dosimetry study to determine how hazardous varying levels of ²³²U are, and how to efficiently produce ²³²U in sufficient quantities.

A dosimetry study was performed to determine the dose hazards due to …

A Volumetric Modulated Arc Therapy Retrospective Planning Study Of Left Sided Chest Wall Treatments With And Without Bolus, Telly J. Armstrong

Culminating Experience Projects

Introduction

VMAT planning techniques have been used more to treat difficult‐to‐plan post‐mastectomy cases. The primary advantage of VMAT is the better performance at intermediate-high dose sparing and mean heart dose, without sacrificing target coverage. The location of the chest wall leads to clinical target volumes (CTV) adjoined to the skin which would generate a planning target volume (PTV) located outside the body. To overcome these limitations a virtual bolus is used during optimization. The purpose of the study is to evaluate if a VMAT technique without a bolus, with 5 mm virtual bolus, or 1 cm virtual bolus provides better …

Verification And Validation Of Radiation Protection Factors From Monte Carlo Simulations, William J. Erwin

Theses and Dissertations

This dissertation describes the verification and validation of methods for producing radiation protection factors (RPFs) using experiments and Monte Carlo N-Particle 6 (MCNP6) simulations. RPF validation of a steel enclosure using a plutonium-beryllium source produced a validated RPF with statistically significant agreement between neutron MCNP6 models and experiments and a gamma protection factor (GPF) with statistically significant agreement to the measured GPF. Efforts to validate more complex enclosures using the Fast Burst Reactor (FBR) yielded the first-ever direct measurements of this reactor’s prompt gamma emission spectrum and revealed irreconcilable differences between the FBR facility-provided source spectrum and spectrometer measurements, resulting …

A Quantitative Study Of Correlations Between Patient Load With The Usage Of Artificial Intelligence Treatment Planning Tools (Auto Planning, Adaptive Rt, Clear Check, Deformable Dose, Auto-Contouring, Ezfluence, Etc.) A United States Context, Casey Joy Ervick

Culminating Experience Projects

Abstract

Introduction:

Artificial intelligence (AI) is the process of automating tasks that were traditionally done manually. AI can be used throughout the dosimetry treatment planning process for external beam radiation treatments. Artificial intelligence has the opportunity to help reduce treatment planning time and help to increase the quality of treatment plans. The workload of cancer treatment facilities across the United States varies greatly. This study aims to determine if the workload of a treatment facility has an impact upon the usage of artificial intelligence during treatment planning.

Methods:

This study is a qualitative study of 96 survey participants. The survey …

A Dosimetric Study On Photon Beam Energies With And Without A Flattening Filter In Sbrt Treatments For Prostate Cancer, Alexis F. Puruleski

Culminating Experience Projects

Purpose: The role of radiation therapy in managing prostate cancer has developed and improved greatly throughout the years. The purpose of this study was to analyze a newly developing method of treatment practices with two different therapy energies.

Methods: This retrospective study pulled patient data from the facility’s treatment planning system database who had primary prostate cancer treated to the prostate bed. Each patient was planned for the same treatment technique with two different beam energies, 6X and 6FFF (flattening filter free).

Results: A two-sample t-test was done to compare means of the max doses to the bladder, rectum, and …

Delivering Highly-Characterized Low-Dose X-Ray Radiation To Biological Samples, Jaclyn D'Avanzo

All Theses

Since the advent and swift adoption of x-ray imaging in 1986, the understanding of radiation among the general populace has markedly increased as has the average annual radiation exposure. The biological effects of high doses and high dose-rates, particularly related to x-ray radiation, became a concern of the scientific and medical communities within the same year due to the unregulated use of such imaging. The dangers of these high doses sparked extensive studies, health recommendations, and regulations. However, after it became common practice to use the lowest dose necessary to facilitate medical treatment, the research on the biological effects of …

Validation Of Geant4-Based Simulation And Characterisation Of Silicon Dosimeters For Quality Assurance And Beam Monitoring In Microbeam Radiation Therapy, Andrew Dipuglia

University of Wollongong Thesis Collection 2017+

Despite extensive research into improvements in brain cancer treatment, the cancer re- lated mortality since 1983 has remained nearly constant. Synchrotron-based radiotherapy microbeam radiation therapy (MRT) has emerged as a promising novel treatment aimed at improving tumour control while reducing normal tissue toxicities in brain cancer pa- tients. The complex features of the synchrotron source and microbeam (MB) array re- quires careful consideration in the quest towards the progression of MRT to clinical trials. The research presented in this PhD thesis aims contributes to the international field of re- search through advances in MRT quality assurance (QA) processes relating to …

Dosimetry Of Photon And Proton Mri Guided Radiotherapy Beams Using Silicon Array Dosimeters, Trent James Causer

University of Wollongong Thesis Collection 2017+

The integration of online magnetic resonance imaging (MRI) with photon and pro-ton radiotherapy has potential to overcome the soft tissue contrast limitations of the current standard of care kV-image guided radiotherapy in some challenging treat-ment sites. By directly visualising soft tissue targets and organs at risk, removing the dependence on surrogates for image guidance, it is expected there will be a decrease in the geometric uncertainties related to daily patient setup. This new approach to image guided radiotherapy presents unique challenges due to the permanent mag-netic field of the integrated MRI unit. The trajectory of charged particles including dose depositing …

Quality Assurance Dosimetry In Particle Therapy, Benjamin James

University of Wollongong Thesis Collection 2017+

This thesis presents research pertaining to the application of silicon microdosimetry for radiation protection and quality assurance (QA) in heavy ion therapy. Heavy ion therapy has a number of advantages compared to conventional photon therapy, particularly for treating tumours near high risk organs, due to its greater conformal energy deposition. However, successful treatment with heavy ions depends largely on knowledge of the relative biological effectiveness (RBE) of the radiation produced by primary and secondary charged particles. Sparsely ionising radiation such as x-rays, electrons and gamma rays produce approximately equivalent biological effects for the same absorbed dose. However, heavy ions produce …

High Spatial Resolution Fibre-Optic Dosimetry, James Archer

University of Wollongong Thesis Collection 2017+

External beam radiation therapy (EBRT) is one of the most common forms of therapy used to treat cancers worldwide. New EBRT modalities are being developed across a range of therapies to improve patient outcomes. With these new therapies comes unique challenges for dosimetry and quality assurance which is vital for safe and effective treatments. Microbeam radiation therapy (MRT) is a novel form of EBRT that uses spatially fractionated synchrotron sourced kilovoltage x-rays to deliver highly-targeted planes of x-rays to the target volume. These microbeams are typically 25 – 50 µm in thickness, with a peak-to-peak separation of 200 – 400 …

Dosimetry And 4d Modelling For Advanced Radiotherapy Treatments: Towards Mri-Guided Lung Sbrt, Natalia F. Roberts

University of Wollongong Thesis Collection 2017+

A major problem for radiation therapy of lung cancer is respiration-induced motion, which causes both the tumour and surrounding normal tissue to move during treatment. This motion often results in inadequate target coverage and increases the likelihood of additional healthy tissue exposure; therefore detracting from the therapeutic benefits and increasing the risk of radiation induced toxicity. Some motion-management techniques include additional treatment margins to encompass the range of tumour motion, monitoring the respiratory cycle and treating only when in a particular phase i.e. respiratory gating, or imaging the tumour during treatment and adapting the radiation beam aperture to follow the …

Development Of A System For Comprehensive In-Vivo Validation Of Transrectal Ultrasound Based High Dose Rate Prostate Brachytherapy Treatments, Joel Poder

University of Wollongong Thesis Collection 2017+

High dose rate (HDR) brachytherapy is a treatment modality commonly used for the treatment of prostate cancer. In this technique, radiation is emitted from within the prostate, allowing for high doses to be delivered to the prostate whilst still sparing the surrounding organs at risk such as the urethra, bladder, and rectum. However, due to the close proximity of these organs at risk to the prostate, and therefore the radiation source, there is potential that small errors in placement of the source may lead to substantial changes in the delivered dose distribution. Consequently, these errors may lead to significant post-treatment …

Kilovoltage Range X-Ray Characterisation And Diagnostic Applications Of The Moskin Dosimeter, Nathan Kenneth Thorpe

University of Wollongong Thesis Collection 2017+

The use of diagnostic imaging services has been increasing significantly over recent decades as the availability and the sophistication of diagnostic imaging equipment has expanded. This has resulted in improved patient outcome through earlier and more accurate diagnoses at cost of increasing radiation exposure to the general populace. This may result in an increased incidence of radiation-induced conditions and cancer. Monitoring the radiation exposures during these procedures is crucial to preventing ra-diation induced conditions and minimising radiation exposure both to patients and to operators of radiation imaging technologies where possible. This thesis investigated the applications of the MOSkin dosimeter, in …

High Resolution Radiation Dosimetry In An Mri-Linac Using Novel Silicon Array Detectors, Sarah Jane Alnaghy

University of Wollongong Thesis Collection 2017+

The integration of a linear accelerator with magnetic resonance imaging, or MRI-linac, provides a means to acquire gated images of the tumour and surrounding organs. This may enable more accurate radiation therapy treatment with the potential for motion-tracking using these images. Challenges of this kind of treatment include effects due to the magnetic and radiofrequency (RF) fields on the dose distribution. Magnetic fields in uence charged particles via the Lorentz force. The `Electron Return Effect' (ERE) and asymmetry of the point spread kernel are dosimetric effects due to a magnetic field that is transversely orientated with respect to the radiation …

Development And Characterization Of Solid-State Detectors For Medical Dosimetry In Intensity Modulated Radiation Therapy And Stereotactic Radiosurgery, Sultan Fahad Alhujaili

University of Wollongong Thesis Collection 2017+

In the last decade, the majority of radiotherapy treatments are delivered via advanced radiotherapy technologies such as intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT) and stereotactic body radiation therapy (SBRT). The unique properties of these modalities such as small and irregular field shapes, continuously varying fluence/dose rates, and beam delivered at several different angles and from non-coplanar directions produces non-uniform, modulated intensity and conformed absorbed dose distribution which in turn improves the outcome of the treatment. However, the complexities associated with these technologies can create large deviations in treatment dose, requiring extensive dose measurement verification and quality assurance (QA) …

Audiometric Status, Self-Perception Of Hearing Disorders, And Noise Dose In Audio Post-Production Engineers, Laura M. Sinnott

Dissertations, Theses, and Capstone Projects

Numerous studies have assessed the risk of hearing injury for musicians and other sound professionals due to excessive sound exposure, however no studies have investigated whether audio post-production engineers have this same risk. This preliminary study first measured 23 participants’ hearing thresholds and prevalence of audiometric notches. Second, a questionnaire, the Questionnaire for Sound Professionals (QUSP), was designed and administered to determine whether correlations between audiometric status and self-perception of hearing loss and hearing disorders existed. Third, sound dosimetry measurements were conducted at film audio post-production studios to assess whether this population is at risk for permanent hearing loss due …

Development Of A Positron-Emitting Surrogate Microsphere For Image-Based Dosimetry In Yttrium-90 Radioembolization Therapy, Gregory D. Chambers

Nuclear Engineering ETDs

Radioembolization of liver tumors using yttrium-90 (Y-90) labeled microspheres is a proven method of treatment. The primary decay mode of Y-90 is beta-minus decay. The electrons produced during decay deliver a cytotoxic radiation dose in a localized volume. The radiation dose is sufficient to kill tumor cells yet spare the normal liver. The Y-90 microspheres are delivered via a catheter that has been placed in an artery that supplies blood to the tumor. Microspheres are injected and the blood distributes the microspheres. The current practice involves two separate procedures. The first procedure is an assessment of the vasculature of the …

2d Monolithic Silicon Detectors For Dosimetry In Small Beam Radiotherapy (Stereotactic Radiotherapy), Khalsa Ali Al Shukaili

University of Wollongong Thesis Collection 2017+

Radiation Therapy is one type of cancer’s treatment, which aims to kill or control tumour cells by using high energy radiation. However, it can affect both normal and tumour cells. Due to that, scientists worked to develop a new treatment technique of radiation delivery that focuses the high prescribed dose on the small localized area of tumour cells and protects the normal cells. This focal irradiation technique is called Stereotactic Radiosurgery (SRS). Using SRS allows the treatment of hard-to-reach lesions where surgery is not possible because of the risks resulting in the surgical procedures. The commissioning and Quality Assurance of …