Search for dissertations about: "Transmission tomography"

Showing result 1 - 5 of 71 swedish dissertations containing the words Transmission tomography.

2. 1. 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

4. 2. Attenuation correction in pulmonary and myocardial single photon emission computed tomography

   Author : Helén Almquist; Lund Klinisk fysiologi; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Klinisk fysiologi; tomography; medical instrumentation; radiology; Clinical physics; downscatter; myocardial perfustion; ventilation-perfusion ratio; radiologi; pulmonary density; pulmonary perfusion; attenuation correction; SPECT; transmission measurement; tomografi; medicinsk instrumentering;

   Abstract : The objective was to develop and validate methods for single photon emission computed tomography, SPECT, allowing quantitative physiological and diagnostic studies of lung and heart. A method for correction of variable attenuation in SPECT, based on transmission measurements before administration of an isotope to the subject, was developed and evaluated. READ MORE

5. 3. Transmission Electron Tomography and In-situ Analysis of Nanowires

   Author : Axel Persson; NanoLund: Centre for Nanoscience; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Transmission electron microscopy TEM ; Electron tomography; Nanowires NWs ; Aerotaxy; In-situ;

   Abstract : As semiconducting nanowires have promising applications for materials science, nanoelectronics and photovoltaic devices, absolute control of their structure, morphology and composition is a prerequisite for their functionality. Nanowires, grown through the vapor-liquid-solid (VLS) method, exhibit a complex relationship between their liquid seed particle and what properties, such as the aforementioned ones, the wire adopts in the end. READ MORE

6. 4. 3D nano-tomography using coherent X-rays

   Author : Maik Kahnt; Lunds universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ptychography; Tomography; Phase reconstruction; X-ray microscopy;

   Abstract : X-rays allow to non-destructively investigate biological, chemical or physical processes at the nano-scale. Their high penetration depth in matter allows to investigate samples even inside sample environments, which would be difficult with complementary methods such as transmission electron microscopy (TEM). READ MORE

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

   Author : Stefan Johnsson; Lund Medicinsk strålningsfysik; []
   Keywords : 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;

   Abstract : 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. READ MORE