Sökning: "collimator"
Visar resultat 1 - 5 av 25 avhandlingar innehållade ordet collimator.
1. Development of optimized radiation therapy using external electron and photon beams
Sammanfattning : 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. LÄS MER
2. Improvements of SPECT by a new collimator design and simultaneous transmission-emission tomography
Sammanfattning : 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. LÄS MER
3. Corrections for improved quantitative accuracy in SPECT and planar scintigraphic imaging
Sammanfattning : 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. LÄS MER
4. Methods for selection and optimisation of radiotherapy and early therapy evaluation in breast cancer
Sammanfattning : 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. LÄS MER
5. Gamma radiation techniques for non-destructive post-irradiation examination of nuclear fuel : Predicting performance and optimizing instrument design
Sammanfattning : 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). LÄS MER