The Classroom Problem: An algorithm to find an optimal classroom lay-out

"Who do you want to sit next to?'' In this thesis we develop an algorithm that optimizes a classroom lay-out based on this question. Besides the couples that sit next to each other, it also matters who sits in front (or behind). Even the relations across the aisles matter in the lay-out optimization. Each student chooses three other students and...

Treatment planning of intensity modulated proton therapy by using sparsity inducement for spot selection

In intensity modulated proton therapy (IMPT), patients are irradiated with small spots, that deliver a local dose to the tumor. The number of possible spots to choose from is virtually infinite, but practically limited, which requires a spot selection. This spot selection should result in an optimal treatment plan, i.e., to deliver a sufficient...

Identifying the most relevant cost-functions for radiotherapy treatment planning with multicriteria optimisation

Cancer is a disease that one of every three people will get in The Netherlands. One of the treatment methods for this disease is radiotherapy. Approximately half of all cancer patients will get radiotherapy at some point of their treatment. During radiotherapy cancer cells are destroyed with ionizing radiation, but healthy cells get destroyed...

Beamlet and energy layer reduction in IMPT by sparsity induced optimisation

In Intensity Modified Proton Therapy, the number of energy layers and the number of beamlets determine the radiation time and the plan calculation time. The purpose of this research project is to test sparsity inducing terms to reduce both the energy layers and the beamlets.

Local Pareto navigation for treatment plan trade-off analysis in radiotherapy

The method Erasmus-iCycle is able to generate a treatment plan for cancer patients, based on the patient's anatomy and a predefined wish list. This wish list contains goals for different organs near the tumour, listed by priority. However, it is not certain that the generated iCycle plan is the best fit for an individual patient, since every...

Using collected patient’s data to configure treatment plans for new patients in radiotherapy

Nowadays around 50% of all patients diagnosed with cancer are treated with radiotherapy. Radiotherapy uses ionizing beams to irradiate the tumour. This radiation damages and destroys cells, such that it is impossible for this cell to grow and divide. When the tumour is irradiated, the surrounding healthy tissues gets damaged as well. The goal is...

Fast re-planning for radiotherapy by using the reference point method

When a patient is diagnosed with cancer, a number of treatments is possible. About half of these patients is treated with radiotherapy. This is a multi-disciplinary field of research, where mathematics, physics and medicine come together. In this thesis the focus will lie on prostate cancer. One of the main problems with this type of cancer is...

Inverse Modeling for Magnetic Signature Monitoring of Naval Ships

We propose a prediction model that predicts the magnetic signature of a naval ship, based on on-board measurements of the magnetic field.

Optimale importance sampling in Markovketens: Efficiënte simulatie zeldzame gebeurtenissen

Toepassing importance sampling op credit risk probleem met onafhankelijke schuldenaren.

Modelling Turbulent Non-Premixed Combustion in Industrial Furnaces

Measuring the temperature distribution inside the rotary kilns, using thermocouples for instance has proven to be difficult due to the harsh operating conditions of the kiln. Numerical modelling of turbulent combustion and the associated physical phenomenon thus proves to be an indispensable tool towards predicting the kiln operating conditions....

Multicriteria Optimization for Radiotherapy

Radiotherapy is one of the main treatments for cancer, and a multi-disciplinary field of research, mostly involving medicine, physics and mathematics. The focus of this thesis lies in improvements for the treatment planning, which is a multi-criteria process. We have been constructing a new method to form the Pareto front for certain objectives....

Investigation of Different Solvers for Radiotherapy Treatment Planning Problems

Radiotherapy treatment planning involves solving inequality constrained minimization problems. The currently used interior point solver performs well, but is considered relatively slow. In this thesis we investigate two different solvers based on the logarithmic barrier method and Sequential Quadratic Programming (SQP) respectively. We argue...

Lexicographic Reference Point Method for Automatic Treatment Planning in Radiation Therapy

Treatment plan generation in radiation therapy is a multicriteria optimization problem, in which multiple, often conflicting, criteria need to be optimized simultaneously. Several methods can be used to obtain Pareto optimal treatment plans, meaning that no criterion can be improved without deteriorating another criterion. The focus is on the 2...

Multileaf collimator optimisation for column generation in radiotherapy

Radiation therapy is a form of therapy for cancer treatments, where ionizing radiation is used to eradicate malignant cells. The patient is treated with a device called a linear particle accelerator. It contains a source, from which photons are emitted. Constructing an optimal treatment plan for radiation therapy involves optimising the angles...

Slimme multi-criteria optimalisatie voor radiotherapie

For multi-criteria optimization of radiation therapy treatment planning, several methods can be used. One method, the 2-phase ?-constraint method, is to optimize each criterium, one at a time, to find an optimal radiation plan. The disadvantage of this method is that it takes a lot of computation time. The purpose of this thesis is to...

Improving the tumor coverage by dynamic steering in Hyperthermia

Hyperthermia is a cancer treatment in which tumours are heated. This makes them more vulnerable to other cancer treatments like radiotherapy and chemotherapy. In this report we search for a way to improve the tumour coverage. Here the tumour coverage is how much of the tumour is heated.

A calibration procedure for a planning-guided application of head and neck hyperthermia

Hyperthermia, heating of tissue, is a method of cancer treatment. Due to dispositioning of the patient, the treatment will not be optimal. In this thesis we try to correct for such errors. This bachelorproject was performed at the Hyperthermia Unit of the Erasmus Medical Centre.

Verificatie van een model voor deformaties van de prostaat voor radiotherapie

Een promovendus bij DIAM is bezig om de deformaties van de prostaat preciezer te modelleren, en alleen de echt voorkomende deformaties mee te nemen in de optimalisering van het bestralingsplan. Het is de verwachting dat kwetsbare organen in de buurt van de prostaat meer ontzien kunnen worden dan met uniforme marges. Bij het bestralen wordt er...