Sökning: "Collimator Scattered Radiation"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Collimator Scattered Radiation.

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

   Författare :Mats Åsell; Henk Huizenga; Stockholms universitet; []
   Nyckelord :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;

   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

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

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

   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

4. 3. Beam Modelling for Treatment Planning of Scanned Proton Beams

   Författare :Peter Kimstrand; Bengt Glimelius; Erik Traneus; Nina Tilly; Anders Ahnesjö; Thomas Bortfeld; Uppsala universitet; []
   Nyckelord :Radiation sciences; proton therapy; treatment planning; beam modelling; dose calculation; Monte Carlo; Strålningsvetenskap;

   Sammanfattning : Scanned proton beams offer the possibility to take full advantage of the dose deposition properties of proton beams, i.e. the limited range and sharp peak at the end of the range, the Bragg peak. LÄS MER

5. 4. Development and evaluation of an independent system for absorbed dose calculations in radiotherapy

   Författare :Stefan Johnsson; Lund Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; medicinsk instrumentering; tomografi; radiologi; Klinisk fysiologi; tomography; medical instrumentation; radiology; Clinical physics; cancer; Cytologi; onkologi; cancerology; oncology; Cytology; PDA; mini-phantom; in-air equivalence; primary kerma; transmission measurement; stopping power ratio; entrance dose; beam quality; quality control; error prevention; monitor unit calculation; radiation therapy; dose calculation;

   Sammanfattning : The aim of this work was to develop, implement and evaluate an independent system with which to calculate the absorbed dose, delivered by high-energy X-ray beams, to the prescription point and the depth of dose maximum. The introduction of such a system in the clinical routine may help ensure high-quality treatment and avoidance of errors which may jeopardise the clinical outcome of the treatment (i. LÄS MER

7. 5. Studies of clinical proton dosimetry using Monte Carlo simulation and experimental techniques

   Författare :Joakim Medin; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Proton dosimetry; Proton stopping power; Monte Carlo; Proton stopping-power ratios; Ionization chamber calibration; medicinsk strålningsfysik; Medical Radiation Physics;

   Sammanfattning : The present work aims at improving clinical proton dosimetry based on ionization chambers, and to bring its state of development closer to the corresponding status of conventional photon and electron dosimetry. In order to accomplish this, both theoretical and experimental methods have been used. LÄS MER