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Visar resultat 1 - 5 av 10 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Characterisation and application of photon counting X-ray detector systems

   Författare :Börje Norlin; Christer Fröjdh; Hans-Erik Nilsson; Sherwood Parker; Mittuniversitetet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Monte Carlo simulation; Three-dimensional; X-ray flouriscence; Charge transport; Semiconductor materials; Image sensors; CdTe; Photon counting; Synchrotron radiation; Material recognition; X-ray; Pixel Detector; Silicon; Charge sharing; Imaging; Medipix; Spectroscopy; Dental diagnosis; Image quality; Energy weighting; Electronics; Elektronik;

   Sammanfattning : This thesis concerns the development and characterisation of X-ray imaging systems based on single photon processing. “Colour” X-ray imaging opens up new perspectives within the fields of medical X-ray diagnosis and also in industrial X-ray quality control. LÄS MER

3. 2. Tidig aritmetisk kunskapsbildning : Ett radikalkonstruktivistiskt perspektiv

   Författare :Göta Eriksson; Siv Fischbein; Olof Magne; Stockholms universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Radical Constructivism; model building; ontogenesis of arithmetic; counting scheme; cognitive system of self-regulation and self-organising; conceptual progression; longitudinal approach; special education.; Education; Pedagogik;

   Sammanfattning : From a Radical Constructivist (RC) perspective this thesis deals with children’s construction of early arithmetic learning as an evolving process through the cognitive system of self-regulation and self-organising. Thus the child’s learning must guide teaching. RC views early arithmetic as verbal and preceding the system of written arithmetic. LÄS MER

4. 3. Characterization and Optimization of Silicon-strip Detectors for Mammography and Computed Tomography

   Författare :Han Chen; Mats Danielsson; cheng xu; Andrew Maidment; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; mammography; anti-scatter grid; photon-counting; spectral computed tomography; silicon strip; ASIC; energy resolution; Compton scatter; material decomposition; K-edge imaging; Medical Technology; Medicinsk teknologi;

   Sammanfattning : The goal in medical x-ray imaging is to obtain the image quality requiredfor a given detection task, while ensuring that the patient dose is kept as lowas reasonably achievable. The two most common strategies for dose reductionare: optimizing incident x-ray beams and utilizing energy informationof transmitted beams with new detector techniques (spectral imaging). LÄS MER

5. 4. Spectral Mammography with X-Ray Optics and a Photon-Counting Detector

   Författare :Erik Fredenberg; Mats Danielsson; Björn Cederström; Jeffrey H. Siewerdsen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; 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; mammography; x-ray optics; photon counting; spectral shaping; spectral imaging; collimation; radiation dose; signal-to-noise ratio; quantum noise; anatomical noise; spatial resolution; x-ray flux; ; TECHNOLOGY; TEKNIKVETENSKAP; Engineering physics; Teknisk fysik; Optical physics; Optisk fysik; Other engineering physics; Övrig teknisk fysik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik; Medical engineering; Medicinsk teknik; Radiological research; Radiologisk forskning;

   Sammanfattning : Early detection is vital to successfully treating breast cancer, and mammography screening is the most efficient and wide-spread method to reach this goal. Imaging low-contrast targets, while minimizing the radiation exposure to a large population is, however, a major challenge. LÄS MER

7. 5. Methods of image acquisition and calibration for x-ray computed tomography

   Författare :Martin Sjölin; Mats Danielsson; J. Webster Stayman; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Medical Technology; Medicinsk teknologi;

   Sammanfattning : X-ray computed tomography (CT) is a common medical imaging device for acquiring high-resolution 3D images of the interior of the human body. The images are formed by mathematical reconstruction from hundreds of planar x-ray images that have been acquired during less then a second. LÄS MER