Essays about: "intensity-modulated radiation therapy"

Showing result 1 - 5 of 16 essays containing the words intensity-modulated radiation therapy.

  1. 1. Direct optimization of dose-volume histogram metrics in intensity modulated radiation therapy treatment planning

    University essay from KTH/Skolan för teknikvetenskap (SCI)

    Author : Tianfang Zhang; [2018]
    Keywords : Optimization; intensity-modulated radiation therapy; DVH functions; dose-at-volume; volume-at-dose; value-at-risk; smooth approximation; kernel density estimation; fluence map optimization; Optimering; intensitetsmodulerad strålterapi; DVH-funktioner; dose-at-volume; volumeat- dose; value-at-risk; slätapproximation; ickeparametrisk skattning; fluensoptimering;

    Abstract : In optimization of intensity-modulated radiation therapy treatment plans, dose-volumehistogram (DVH) functions are often used as objective functions to minimize the violationof dose-volume criteria. Neither DVH functions nor dose-volume criteria, however,are ideal for gradient-based optimization as the former are not continuously differentiableand the latter are discontinuous functions of dose, apart from both beingnonconvex. READ MORE

  3. 2. Robust optimization of radiotherapy treatment plans considering time structures of the delivery

    University essay from Uppsala universitet/Avdelningen för datalogi

    Author : Erik Orvehed Hiltunen; [2018]
    Keywords : Radiation therapy; optimization; interplay effect; lung cancer; 4DCT; RayStation; Strålterapi; optimering; interplay; lungcancer;

    Abstract : Cancer is the second largest mortal disease in Sweden, and high efforts are made to develop the treatment of cancer. One of the main treatment methods is radiotherapy, which uses ionizing radiation to damage the cancerous cells. This has the chance of stopping the cell reproduction, and the goal is to reduce the tumor and stop the tumor growth. READ MORE

  4. 3. Investigation of the prognostic value of CT and PET-based radiomic image features in oropharyngeal squamous cell carcinoma

    University essay from Lunds universitet/Medicinsk strålningsfysik, Lund; Lunds universitet/Sjukhusfysikerutbildningen

    Author : Mohammed Mosad Said; [2016]
    Keywords : Medicine and Health Sciences;

    Abstract : Background Medical data in the form of radiographic routine scans is steadily accumulating. The analysis of such data through automated quantitative methods is believed to produce new information which would allow for more personalization of therapy. The present thesis investigated the use of such methods in head and neck cancer. READ MORE

  5. 4. MRI only radiotherapy using synthetic CT images: Dosimetric accuracy and patient positioning strategies in an MRI only workflow

    University essay from Lunds universitet/Sjukhusfysikerutbildningen; Lunds universitet/Medicinsk strålningsfysik, Lund

    Author : Emilia Persson; [2015]
    Keywords : Medicine and Health Sciences;

    Abstract : Background and purpose: Magnetic resonance imaging (MRI) only radiotherapy has, due to superior soft tissue contrast of MRI and the possible reduction of systematic uncertainties, grown into a promising technique. The purpose of this work is to investigate parts of an MRI only workflow with synthetic computed tomography (sCT) images generated from MRI. READ MORE

  6. 5. Breathing interplay effects during Tomotherapy. A 3D gel dosimetry study

    University essay from Lunds universitet/Sjukhusfysikerutbildningen

    Author : Anna Ljusberg; [2013]
    Keywords : Medicine and Health Sciences;

    Abstract : Tomotherapy delivers intensity modulated radiation therapy, IMRT, which enables highly advanced treatment plans with homogenous absorbed dose coverage of the target with sharp dose gradients to spare surrounding healthy tissue. Helical tomotherapy consists of a linear accelerator mounted on a rotating gantry, the construction is similar to a CT although the energy is in the MV-range instead of kV and extra collimators and beam stopper are inserted [1-3]. READ MORE