Sökning: "Fotonräknande CT"

Visar resultat 1 - 5 av 10 uppsatser innehållade orden Fotonräknande CT.

  1. 1. Improving proton therapy planning with photon-counting spectral computed tomography

    Master-uppsats, KTH/Fysik

    Författare :Karin Larsson; [2023]
    Nyckelord :Proton therapy; Medical imaging; Computed Tomography; Protonterapi; Medicinsk avbildning; Datortomografi;

    Sammanfattning : Proton radiation therapy is an alternative to conventional photon radiation therapy, which accounts for the majority of radiation treatments today. The rationale for using protons in radiation therapy lies in their dose deposition properties; photons deposit a radiation dose inversely proportional to the energy, and therefore tissue depth, while protons exhibit a sharp Bragg peak when traversing matter. LÄS MER

  3. 2. Characterization of Carotid Atherosclerotic Stenosis on Photon-Counting Computed Tomography

    Master-uppsats, Lunds universitet/Sjukhusfysikerutbildningen

    Författare :My Celander; [2023]
    Nyckelord :Medicine and Health Sciences;

    Sammanfattning : Introduction and aim Atherosclerotic stenosis located at the carotid bifurcation accounts for 10% − 20% of all Transient Ischemic Attacks (TIA) and ischemic strokes, which occurs when Atherosclerotic stenosis, or so-called plaque, ruptures. The current method to evaluate carotid atherosclerotic stenosis is to measure the degree of stenosis. LÄS MER

  4. 3. Deep Ring Artifact Reduction in Photon-Counting CT

    Master-uppsats, KTH/Fysik

    Författare :Konstantinos Liappis; [2022]
    Nyckelord :Photon¬counting; Spectral CT; Material Decomposition; Deep learning; Resnet; Ring artifact; Sinogram; Fotonräknande; Spektral datortomografi; Materialdekomposition; Djupinlärning; Resnet; Ringartefakt; Sinogram;

    Sammanfattning : Ring artifacts are a common problem with the use of photon-counting detectors and commercial deployment rests on being able to compensate for them. Deep learning has been proposed as a candidate for tackling the inefficiency or high cost of traditional techniques. LÄS MER

  5. 4. En bildkvalitésutvärdering av två datortomografer i syfte att rättfärdiga ett inköp av en ny datortomograf : En fantomstudie

    Kandidat-uppsats, KTH/Medicinteknik och hälsosystem

    Författare :Molly Burke; Linnéa Gustafsson; [2022]
    Nyckelord :: Computed tomography CT ; Contrast-to-noise ratio CNR ; Radiation dose; Photon-counting detector; Datortomografi CT ; Kontrast-brus-förhållandet CNR ; Stråldos; Fotonräknande detektor;

    Sammanfattning : Antal datortomografiundersökningar har ökat under flera år i Sverige tack vare tekniska utvecklingar och ökad tillgänglighet på sjukvård. Södertälje sjukhus röntgenavdelningen är i behov av att byta ut en utdaterad datortomograf (eng: Computed tomography, CT) och avdelningen för medicinsk teknik har föreslagit ett inköp av en CT med fotonräknande-detektor. LÄS MER

  7. 5. Phase-Contrast Imaging, Towards G2-less Grating Interferometry With Deep Silicon

    Master-uppsats, KTH/Fysik

    Författare :Rickard Brunskog; [2022]
    Nyckelord :Phase-contrast imaging; phase-contrast; CT-scanning; Computed-tomography; 1 micrometer resolution x-ray; grating-less phase-contrast imaging; Faskontraströntgen; faskontrast; CT-skanning; 1 mikrometer upplösning x-ray; gitterlös faskontrast; datortomografi;

    Sammanfattning : Conventional phase-contrast imaging entails stepping an analyser grating across the detector to resolve the interference pattern caused by the x-rays after passing through a series of gratings in a so-called Talbot-Lau interferometer. However, the analyser grating in the interferometer poses a challenge, not only due to the machinery and alignment required but also due to each exposure delivering a dose to the subject. LÄS MER