Sökning: "counting"

Visar resultat 11 - 15 av 253 avhandlingar innehållade ordet counting.

1. 11. A Segmented Silicon Strip Detector for Photon-Counting Spectral Computed Tomography

   Författare :Cheng Xu; Hans Bornefalk; Mats Danielsson; Ami Altman; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; photon counting; spectral computed tomography; silicon strip detector; ASIC; energy resolution; cadmium telluride; charge sharing; Monte Carlo simulation; synchrotron;

   Sammanfattning : Spectral computed tomography with energy-resolving detectors has a potential to improve the detectability of images and correspondingly reduce the radiation dose to patients by extracting and properly using the energy information in the broad x-ray spectrum. A silicon photon-counting detector has been developed for spectral CT and it has successfully solved the problem of high photon flux in clinical CT applications by adopting the segmented detector structure and operating the detector in edge-on geometry. LÄS MER

3. 12. Spectral Photon-Counting Computed Tomography with Silicon Detectors: New Models and Applications

   Författare :Fredrik Grönberg; Mats Danielsson; Mats Persson; Amir Pourmorteza; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; photon-counting; spectral computed tomography; material decomposition; pulse pileup; Compton scatter; image formation; fotonräknande; spektral datortomografi; materialbasupdelning; pulsöverlagring; Comptonspridning; bildbildning; Physics; Fysik;

   Sammanfattning : X-ray computed tomography (CT) is a widely used imaging modality that enables visualization of nearly every part of the human body. It is used for diagnosis of disease and injury as well as medical treatment planning. LÄS MER

4. 13. Digital Mammography with a Photon Counting Detector in a Scanned Multislit Geometry

   Författare :Magnus Åslund; Mats Danielsson; Ehsan Samei; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mammography; digital; photon counting; scanning; detective quantum effciency; scattered radiation; automatic exposure control; Physics; Fysik;

   Sammanfattning : Mammography screening aims to reduce the number of breast cancer deaths by early detection of the disease, which is one of the leading causes of deaths for middle aged women in the western world. The risk from the x-ray radiation in mammography is relatively low but still a factor in the benefit-risk ratio of screening. LÄS MER

5. 14. Quantification and Maximization of Performance Measures for Photon Counting Spectral Computed Tomography

   Författare :Moa Yveborg; Hans Bornefalk; Franz Pfeiffer; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spectral computed tomography; silicon detector; detectability index; photon counting; Hotelling SDNR; material basis decomposition;

   Sammanfattning : During my time as a PhD student at the Physics of Medical Imaging group at KTH, I have taken part in the work of developing a photon counting spectrally resolved silicon detector for clinical computed tomography. This work has largely motivated the direction of my research, and is the main reason for my focus on certain issues. LÄS MER

7. 15. Neutron Multiplicity Counting with the Analysis of Continuous Detector Signals

   Författare :Lajos Nagy; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Kolmogorov equation; fissile material assay; nuclear safeguards; fission chamber; neutron multiplicity counting; master equation;

   Sammanfattning : Neutron multiplicity counting is a non-destructive assay method for determining the mass of fissile materials (primarily plutonium) using the measured values of the singles, doubles and triples detection rates. Traditionally, the detection rates are obtained from the counting statistics of neutron detectors. LÄS MER