Sökning: WFRF:(Chen Han)
> Doktorsavhandling >
Characterization an...
Characterization and Optimization of Silicon-strip Detectors for Mammography and Computed Tomography
-
- Chen, Han, 1986- (författare)
- KTH,Medicinsk bildfysik,Physics of Medical imaging
-
- Danielsson, Mats, Professor (preses)
- KTH,Medicinsk bildfysik
-
- xu, cheng, Doctor (preses)
- KTH,Medicinsk bildfysik
-
visa fler...
-
Maidment, Andrew (opponent)
-
visa färre...
-
(creator_code:org_t)
- ISBN 9789175959191
- STOCKHOLM : KTH Royal Institute of Technology, 2016
- Engelska viii, 73 s.
-
Serie: TRITA-FYS, 0280-316X ; 0280-316X
- Relaterad länk:
-
https://kth.diva-por... (primary) (Raw object)
-
visa fler...
-
https://urn.kb.se/re...
-
visa färre...
Abstract
Ämnesord
Stäng
- 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). Inthis thesis, dose optimization schemes were investigated in two x-ray imagingsystems: digital mammography and computed tomography (CT).In digital mammography, the usefulness of anti-scatter grids was investigatedas a function of breast thickness with varying geometries and experimentalconditions. The general conclusion is that keeping the grid is optimalfor breasts thicker than 5 cm, whereas the dose can be reduced without a gridfor thinner breasts.A photon-counting silicon-strip detector developed for spectral mammographywas characterized using synchrotron radiation. Energy resolution, ΔE/Ein, was measured to vary between 0.11-0.23 in the energy range 15-40 keV, which is better than the energy resolution of 0.12-0.35 measured inthe state-of-the-art photon-counting mammography system. Pulse pileup hasshown little effect on energy resolution.In CT, the performance of a segmented silicon-strip detector developedfor spectral CT was evaluated and a theoretical comparison was made withthe state-of-the-art CT detector for some clinically relevant imaging tasks.The results indicate that the proposed photon-counting silicon CT detector issuperior to the state-of-the-art CT detector, especially for high-contrast andhigh-resolution imaging tasks.The beam quality was optimized for the proposed photon-counting spectralCT detector in two head imaging cases: non-enhanced imaging and Kedgeimaging. For non-enhanced imaging, a 120-kVp spectrum filtered by 2half value layer (HVL) copper (Z = 29) provides the best performance. Wheniodine is used in K-edge imaging, the optimal filter is 2 HVL iodine (Z = 53)and the optimal kVps are 60-75 kVp. In the case of gadolinium imaging, theradiation dose can be minimized at 120 kVp filtered by 2 HVL thulium (Z =69).
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Medicinteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Medical Engineering (hsv//eng)
Nyckelord
- 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
Publikations- och innehållstyp
- vet (ämneskategori)
- dok (ämneskategori)
Hitta via bibliotek
Till lärosätets databas