Search for dissertations about: "collimator"

Showing result 1 - 5 of 25 swedish dissertations containing the word collimator.

  2. 1. Development of optimized radiation therapy using external electron and photon beams

    Author : Mats Åsell; Henk Huizenga; Stockholms universitet; []
    Keywords : Target design; Collimator Scattered Radiation; Collimator Scatter Kernel; Treatment Planning; Radiation Therapy Optimization; Intensity Modulation; Energy Modulation; Beam Modality Combinations; medicinsk strålningsfysik; Medical Radiation Physics;

    Abstract : The development of new intensity modulated radiation therapy (IMRT) techniques and treatment optimization tools makes it desirable to further improve modulation methods by using scanned photon and electron beams. It is shown that the narrowest possible photon beams have the potential to improve the flexibility in dose delivery, speed up the dose delivery and improve the treatment outcome. READ MORE

  4. 2. Improvements of SPECT by a new collimator design and simultaneous transmission-emission tomography

    Author : Shahrokh Kimiaei; Marija Ivanovic; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Gamma camera; SPECT; Emission tomography; Transmission tomography; Planar-concave collimators; Spatial resolution; Other physics; Övrig fysik; medicinsk strålningsfysik; Medical Radiation Physics;

    Abstract : SPECT (Single Photon Emission Computed Tomography) and planar scintigraphy are the most established and world wide-spread nuclear medicine imaging techniques for clinical use today. SPECT is a tomographic technique that allows 3-D visualization of biochemical processes or physiological flow in the human body by external detection of photons from an administered radiopharmaceutical. READ MORE

  5. 3. Corrections for improved quantitative accuracy in SPECT and planar scintigraphic imaging

    Author : Anne Larsson; Lennart Johansson; Katrine Åhlström Riklund; Bertil Axelsson; Umeå universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Quantitative SPECT; scintigraphic imaging; attenuation correction; scatter correction; collimator-detector response; septal penetration; background correction; Monte Carlo simulation; Radiological physics; Radiofysik;

    Abstract : A quantitative evaluation of single photon emission computed tomography (SPECT) and planar scintigraphic imaging may be valuable for both diagnostic and therapeutic purposes. For an accurate quantification it is usually necessary to correct for attenuation and scatter and in some cases also for septal penetration. READ MORE

  6. 4. Methods for selection and optimisation of radiotherapy and early therapy evaluation in breast cancer

    Author : Tomas Jansson; Uppsala universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Oncology; Breast cancer; human; radiotherapy; multi-leaf collimator; breast-conservingsurgery; local recurrence; p53; positron emission tomography; chemotherapy evaluation; Onkologi; Oncology; Onkologi; Oncology; onkologi;

    Abstract : Adjuvant systemic therapy for breast cancer, the most common malignancy in females, increases survival and this has recently also been demonstrated for postoperative radiotherapy. The aims of this study were to develop an optimised radiotherapeutic technique for postoperative treatment, to analyse the association between p53 status in node-negative patients and radiotherapy, to investigate the incidence of in-breast relapses after conservative surgery and radiotherapy and to determine if positron emissiontomography could be useful for early evaluation of polychemotherapy. READ MORE

  7. 5. Gamma radiation techniques for non-destructive post-irradiation examination of nuclear fuel : Predicting performance and optimizing instrument design

    Author : Lorenzo Senis; Peter Andersson; Erik Andersson Sundén; Ane Håkansson; Fabiola Cappia; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Collimated gamma spectroscopy; Gamma emission tomography; Gamma transmission micro-densitometry; Pareto optimization; Post-irradiation examination; Applied Nuclear Physics; Tillämpad kärnfysik;

    Abstract : Collimated gamma-based techniques are widely used to study nuclear fuel, especially for non-destructive post-irradiation examination (PIE). Examples of such techniques include gamma emission tomography (GET) and gamma transmission densitometry (GTD). READ MORE