Treatment planning strategies for proton therapy in the presence of a cranial fixation clip

This thesis outlines the project conducted at HollandPTC for the Master Biomedical Engineering, track Medical Physics, at Delft University of Technology. <br/><br/>Metal implants create dosimetric uncertainties in treatment planning and delivery for proton therapy. The purpose of this thesis was to determine the most suitable treatment planning...

The Influence of Porosity and Flow Rate in an Aquifer on its Temperature Distribution: A mathematical model

Geothermal energy can be promising to help the energy transition. Warm water is pumped up from a geothermal well and after it is cooled down, the cold water is reinjected into the hot aquifer underground. The temperature change could cause chemical balances to be disturbed and result in precipitation on the porous medium of the aquifer. This...

Characterizing the effects of delineation uncertainties in head and neck cancer radiotherapy

The goal of radiotherapy is to maximize the dose to the target while minimizing the dose to normal tissue. Treatment plans are optimized for this goal and dose delivery is improved in accuracy and precision. The optimization is based on the delineations of the volumes of interest on the medical images of the patient. The problem is that these...

Non-Intrusive Multi-Fidelity Reduced Order Modeling using Adaptive Sparse Grids: Analysis of Nuclear Reactors using Non-Intrusive Adaptive Multi-Fidelity Reduced Order Modeling Techniques

Computational power is a challenge when it comes to the high-fidelity modeling of nuclear reactors. Detailed simulations of reactor physics involve complex calculations that require significant computing resources, which can be time-consuming and expensive. Reduced Order Modeling (ROM) allows for an approximation of a complex model by only...

Virtual Reduction of Focal Spot Size in Computed Tomography using Collimation

This thesis aimed to validate Beekman's patent on how collimation could virtually reduce the focal spot size of an existing small-animal cone beam Computed Tomography (CT) system to diminish the penumbra effect. The ever-remaining drive to improve the spatial resolution in CT for enhanced image quality introduces the need for small focal spot...

Simulation of temperature and dose distribution of a proposed minimally invasive treatment of early‐stage breast cancer by combining thermal ablation and LDR brachytherapy using Pd-103 SPIO nanoparticles

Treatment of early stage breast cancer is generally invasive to a patient's daily life while being treated. Therefore, to diminish the physical and psychological impact during and after recovery, a newly proposed minimally invasive therapy for early-stage breast cancer treatment is proposed. Within this study, this proposed treatment is modelled...

Uncertainty Quantification of the Neutronics Model of the U-Battery with Reduced Models

High-fidelity models are computationally intensive to work with in many-query applications, such as the design process of small modular reactors. A reduced order model of the high-fidelity model can still accurately determine the quantities of interest with only a fraction of the computational cost, and thus can potentially solve the...

Physics-Guided Deep Learning for Volumetric-Modulated Arc Therapy Treatment Planning Quality Assurance

Treatment planning for radiation therapy is a complex process, as there are many machine parameters to determine for a treatment. To decrease the required labour and improve the plan quality, auto-planning systems have been developed, which can automatically generate high-quality treatment plans. These plans still have to be checked to ensure...

Conceptual probabilistic treatment planning approaches to deal with microscopic disease as an alternative to the Clinical Target Volume

Radiotherapy is one of the main treatment modalities available to treat cancer. Radiotherapy treatment plans are created based on CT scans of the patient. In such scans the macroscopic tumor is visible, but microscopic disease present in the surrounding tissue cannot be observed. To achieve an optimal clinical outcome, both the macroscopic and...

Delineation uncertainties in radiotherapy: Modeling the effect of delineation uncertainties in radiotherapy with Polynomial Chaos Expansion

The delineation of the regions of interest (ROIs) plays an important role in the radiotherapy workflow. The ROIs include the gross tumor volume (GTV), the clinical target volume (CTV), the planning target volume (PTV) and organs at risk (OARs). There are however uncertainties related to the delineation of the ROIs due to inter­observer...

The increased risk of post-treatment contrast-enhancing brain lesion in IMPT of glioma, and the mitigation thereof in treatment planning

Proton radiotherapy has a dosimetric advantage over photon therapy to spare healthy tissue closely positioned to the tumor mainly due to the absent exit dose. In The Netherlands, the Proton therapy centers currently take a relative biological effectiveness (RBE) of 1.1 compared to photons to deliver an iso-effective treatment. However, initial...

Automated multi-criterial treatment planning for adaptive high-dose-rate brachytherapy for locally advanced cervical cancer

Purpose - To develop and evaluate a fast and automated multi-criterial treatment planning strategy for High-Dose-Rate (HDR) brachytherapy (BT) for patients with locally advanced cervical cancer. This automated strategy avoids suboptimal and slow manual treatment planning and results in reproducible and conformal treatment plans with a clinically...

Sample-holder design and proof-of-principle experiments with protons: biology versus dosimetry

Purpose/Objective: The aim of the thesis project is to design and build a sample-holder that is suited for radiobiological experiments on cell and tissue level in Holland PTC. In order to create accurate dose plans for radiobiological experiments, dosimetry and range calculations need to be worked out. Finally the sample-holder is used for the...

Reduced Order Modelling methodologies for proton therapy applications

In proton therapy, the calculation of the dose distribution is of great importance in order to find the best treatment plan. For a treatment plan with high quality, several error scenarios are investigated, in order to come up with a general plan that suits best in these scenarios. All of the scenarios have a different simulated error, e.g., in...

Improvement of tumour heterogeneity quantification in PET images: A study to design and develop a new PET heterogeneous phantom

In medical images intratumour heterogeneity well translates specific cancer cells properties in a fast and non-invasive way. Medical community and researchers have developed proper tools (texture features, shape features…) permitting the quantification and the analysis of this tumour heterogeneity in particular in PET images. Yet so far, both...