TY  - JOUR
A1  - Heinrichs, U.
A1  - Pietrzyk, U.
A1  - Ziemons, Karl
T1  - Design optimization of the PMT-ClearPET prototypes based on simulation studies with GEANT3
JF  - 2002 IEEE Nuclear Science Symposium Conference Record, Vol. 3
N2  - Within the Crystal Clear Collaboration four centres are developing 2nd generation high performance small animal PET scanners for different kinds of animals and medical applications. The first prototypes are PMT-based systems including depth of interaction (DOI) detection by using a phoswich layer of LSO and LuYAP. The aim of these simulation studies is to optimize sensitivity and spatial resolution of given designs, which vary in FOVs caused by different detector configurations (ring/octagon) and sizes. For this purpose the simulation tool GEANT3 (CERN) was used. The simulations have shown that all PMT designs with one-to-one coupling of crystals have a very nonlinear axial sensitivity profile. By shifting every other PMT 1/4 of a PMT length in axial direction the sampling of the FOVs became more homogeneous. At an energy threshold of 350keV the regression coefficient increases from 0.818 for the non-shifted to 0.993 for the shifted design. Simulations of a point source centred in the FOV (threshold: 350keV) resulted in sensitivities of 4.2% for a 4×20PMT (LSO/LuYAP a 10mm) and 3.8% for a 4×16PMT (LSO/LuYAP a 8mm) ring design. The 3D-MLEM reconstruction of a point source shows the enormous improvement of resolution using a crystal double layer with DOI (3.1mm at 40mm from CFOV) instead of a 20mm single layer (11.9mm).
Y1  - 2003
SN  - 1082-3654
SP  - 682
EP  - 686
ER  - 
TY  - JOUR
A1  - Heinrichs, U.
A1  - Pietrzyk, U.
A1  - Ziemons, Karl
T1  - Design optimization of the PMT-ClearPET prototypes based on simulation studies with GEANT3
JF  - IEEE Transactions on Nuclear Science
N2  - Within the Crystal Clear Collaboration (CCC), four centers are developing second generation high performance small animal positron emission tomography (PET) scanners for different kinds of animals and medical applications. The first prototypes are photomultiplier tube (PMT)-based systems including depth of interaction (DOI) detection by using a phoswich layer of lutetium oxyorthosilicate (LSO) and lutetium yttrium aluminum perovskite (LuYAP). The aim of these simulation studies is to optimize sensitivity and spatial resolution of given designs, which vary in fields of view (FOVs) caused by different detector configurations (ring/octagon) and sizes. For this purpose the simulation tool GEANT3 (CERN, Geneva, Switzerland) was used.
Y1  - 2003
SN  - 0018-9499
VL  - 50
IS  - 5
SP  - 1428
EP  - 1432
ER  - 
TY  - JOUR
A1  - Streun, M.
A1  - Brandenburg, G.
A1  - Larue, H.
A1  - Saleh, H.
A1  - Zimmermann, E.
A1  - Ziemons, Karl
A1  - Halling, H.
T1  - Pulse shape discrimination of LSO and LuYAP scintillators for depth of interaction detection in PET
JF  - 2002 IEEE Nuclear Science Symposium Conference Record, Vol. 3
N2  - A feasible way to gain the depth of interaction information in a PET scanner is the use of phoswich detectors. In general the layer of interaction is identified front the pulse shape of the corresponding scintillator material. In this work pulses from LSO and LuYAP crystals were investigated in order to find a practical method of distinguishing. It turned out that such a pulse processing could he kept simple due to an additional slow component in the light decay of the LuYAP pulse. At the same time the short decay time guarantees that the major amount of the light output is still collected within a short pulse recording time.
Y1  - 2003
SN  - 1082-3654
SP  - 1636
EP  - 1639
ER  - 
TY  - JOUR
A1  - Streun, M.
A1  - Brandenburg, G.
A1  - Larue, H.
A1  - Saleh, H.
A1  - Zimmermann, E.
A1  - Ziemons, Karl
A1  - Halling, H.
T1  - Pulse shape discrimination of LSO and LuYAP scintillators for depth of interaction detection in PET
JF  - IEEE Transactions on Nuclear Science
N2  - A feasible way to gain the depth of interaction information in a positron emission tomography scanner is the use of phoswich detectors. In general, the layer of interaction is identified from the pulse shape of the corresponding scintillator material. In this work, pulses from LSO and LuYAP crystals were investigated in order to find a practical method of distinguishing. It turned out that such a pulse processing could be kept simple because of an additional slow component in the light decay of the LuYAP pulse. At the same time, the short decay time guarantees that the major amount of the light output is still collected within a short pulse recording time.
Y1  - 2003
SN  - 0018-9499
VL  - 50
IS  - 3
SP  - 344
EP  - 347
ER  -