TY  - CHAP
A1  - Peters, H.
A1  - Ziemons, Karl
A1  - Dammers, J.
A1  - Müller-Veggian, Mattea
ED  - Nenonen, Jukka
T1  - Continuous head motion detection during MEG measurement using head location coils
T2  - Proceedings of the 12th International Conference on Biomagnetism : August 13 - 17, 2000, Helsinki University of Technology, Espoo, Finland
Y1  - 2001
SN  - 951-22-5401-8
N1  - Biomag <12, 2000, Espoo> ; Teknillinen Korkeakoulu <Helsinki> ; International Conference on Biomagnetism <12, 2000, Espoo>
PB  - Helsinki Univ. of Technology, Laboratory of Biomedical Engineering
CY  - Espoo
ER  - 
TY  - CHAP
A1  - Streun, M.
A1  - Al-Kaddoum, R.
A1  - Parl, C.
A1  - Pietrzyk, U.
A1  - Ziemons, Karl
A1  - Waasen, S. van
T1  - Simulation studies of optical photons in monolithic block scintillators
T2  - 2011 IEEE Nuclear Science Symposium Conference Record (NSS/MIC)
N2  - The interest in PET detectors with monolithic block scintillators is growing. In order to obtain high spatial resolutions dedicated positioning algorithms are required. But even an ideal algorithm can only deliver information which is provided by the detector. In this simulation study we investigated the light distribution on one surface of cuboid LSO scintillators of different size. Scintillators with a large aspect ratio (small footprint and large height) showed significant position information only for a minimum interaction depth of the gamma particle. The results allow a quantitative estimate for a useful aspect ratio.
Y1  - 2012
SN  - 978-1-4673-0120-6 (electronic ISBN)
SN  - 978-1-4673-0118-3 (print ISBN)
U6  - http://dx.doi.org/10.1109/NSSMIC.2011.6154621
SP  - 1380
EP  - 1382
PB  - IEEE
CY  - New York
ER  - 
TY  - CHAP
A1  - Olderog, M.
A1  - Mohr, P.
A1  - Beging, Stefan
A1  - Tsoumpas, C.
A1  - Ziemons, Karl
T1  - Simulation study on the role of tissue-scattered events in improving sensitivity for a compact time of flight compton positron emission tomograph
T2  - 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)
N2  - In positron emission tomography improving time, energy and spatial detector resolutions and using Compton kinematics introduces the possibility to reconstruct a radioactivity distribution image from scatter coincidences, thereby enhancing image quality. The number of single scattered coincidences alone is in the same order of magnitude as true coincidences. In this work, a compact Compton camera module based on monolithic scintillation material is investigated as a detector ring module. The detector interactions are simulated with Monte Carlo package GATE. The scattering angle inside the tissue is derived from the energy of the scattered photon, which results in a set of possible scattering trajectories or broken line of response. The Compton kinematics collimation reduces the number of solutions. Additionally, the time of flight information helps localize the position of the annihilation. One of the questions of this investigation is related to how the energy, spatial and temporal resolutions help confine the possible annihilation volume. A comparison of currently technically feasible detector resolutions (under laboratory conditions) demonstrates the influence on this annihilation volume and shows that energy and coincidence time resolution have a significant impact. An enhancement of the latter from 400 ps to 100 ps leads to a smaller annihilation volume of around 50%, while a change of the energy resolution in the absorber layer from 12% to 4.5% results in a reduction of 60%. The inclusion of single tissue-scattered data has the potential to increase the sensitivity of a scanner by a factor of 2 to 3 times. The concept can be further optimized and extended for multiple scatter coincidences and subsequently validated by a reconstruction algorithm.
Y1  - 2021
SN  - 978-1-7281-7693-2
U6  - http://dx.doi.org/10.1109/NSS/MIC42677.2020.9507901
N1  - 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 31 Oct.-7 Nov. 2020, Boston, MA, USA
PB  - IEEE
ER  -