Sökning: "Tomography"

Visar resultat 21 - 25 av 1143 avhandlingar innehållade ordet Tomography.

  1. 21. Attenuation correction in pulmonary and myocardial single photon emission computed tomography

    Författare :Helén Almquist; Lund Klinisk fysiologi; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER

  3. 22. Experimental Evaluation of a Microwave Tomography System for Breast Cancer Detection

    Författare :Tomas Rydholm; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tomography; microwave imaging; phantom; breast cancer;

    Sammanfattning : Microwave tomography is a potential candidate for future breast-cancer screening or diagnosis. Contrary to x-rays, microwaves are non-ionizing and therefore not a health risk by their own. The examination procedure would also be more comfortable for the patient compared to conventional mammography since no compression of the breast is needed. LÄS MER

  4. 23. Conventional spiral and low-dose computed mandibular tomography for dental implant planning

    Författare :Annika Ekestubbe; Göteborgs universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Artifacts; Dental Implantation; Endosseous; methods; Dental Implants; Humans; Jaw; Edentulous; radiography; Mandible; radiography; Patient Care Planning; Phantoms; Imaging; Radiation Dosage; Radiography; Dental; methods; Reproducibility of Results; Tomography; X-Ray; instrumentation; methods; Tomography; X-Ray Computed; methods;

    Sammanfattning : Absorbed doses to radiosensitive organs in the head and neck from pre-implant conventional hypocycloidal, conventional spiral and computed tomography (CT) were measured with thermoluminescent dosimeters in an anthropomorphic phantom head. From conventional tomography organ doses, except to the major salivary glands, were below 0.2 mGy. LÄS MER

  5. 24. 3D Reconstruction of Porous and Poorly Conductive Soft Materials using FIB-SEM Tomography

    Författare :Cecilia Fager; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; insulating material; 3D; interconnectivity; focused ion beam; tomography; polymer film; scanning electron microscopy;

    Sammanfattning : Focused ion beam combined with scanning electron microscope (FIB-SEM) is a powerful tool that can be utilised to reveal the internal microstructure of materials. It basically uses ions to make cross-sections with high precision and electrons to image the cross-section surface with high spatial resolution. LÄS MER

  7. 25. 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