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Showing result 1 - 5 of 13 essays matching the above criteria.

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

   University essay from KTH/Fysik

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

   Abstract : 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. READ MORE

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

   University essay from Lunds universitet/Sjukhusfysikerutbildningen

   Author : My Celander; [2023]
   Keywords : Medicine and Health Sciences;

   Abstract : 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. READ MORE

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

   University essay from KTH/Fysik

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

   Abstract : 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. READ MORE

5. 4. Detective Quantum Efficiency in the Image Domain

   University essay from KTH/Fysik

   Author : Per Lundhammar; [2022]
   Keywords : detective quantum efficiency; linear systems theory; projection domain; image domain; x-ray imaging; detektiv kvanteffektivitet; linjär-systemteori; projektionsdomän; bilddomän; röntgenavbildning;

   Abstract : We investigate the signal and noise transform characteristics from the projection domain to the image domain in a linear systems theory framework and predictions of the DQE within this framework are made. A simulation study of a photon counting silicon detector is made from which the energy information is used in order to produce synthetic monoenergetic images. READ MORE

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

   University essay from KTH/Fysik

   Author : Rickard Brunskog; [2022]
   Keywords : 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;

   Abstract : 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. READ MORE