TY  - JOUR
A1  - Khodaverdi, M.
A1  - Chaziioannou, A. F.
A1  - Weber, S.
A1  - Ziemons, Karl
A1  - Halling, H.
A1  - Pietrzyk, U.
T1  - Investigation of different microCT scanner configurations by GEANT4 simulations
JF  - 2003 IEEE Nuclear Science Symposium Conference Record, Vol. 4
N2  - This study has been performed to design the combination of the new ClearPET TM (ClearPET is a trademark of the Crystal Clear Collaboration), a small animal Positron Emission Tomography (PET) system, with a microComputed Tomography (microCT) scanner. The properties of different microCT systems have been determined by simulations based on GEANT4. We demonstrate the influence of the detector material and the X-ray spectrum on the obtained contrast. Four different detector materials (selenium, cadmium zinc telluride, cesium iodide and gadolinium oxysulfide) and two X-ray spectra (a molybdenum and a tungsten source) have been considered. The spectra have also been modified by aluminum filters of varying thickness. The contrast between different tissue types (water, air, brain, bone and fat) has been simulated by using a suitable phantom. The results indicate the possibility to improve the image contrast in microCT by an optimized combination of the X-ray source and detector material.
Y1  - 2004
SN  - 1082-3654
SP  - 2989
EP  - 2993
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
A1  - Heinrichs, U.
A1  - Streun, M.
A1  - Pietrzyk, U.
T1  - Validation of GEANT3 simulation studies with a dual-head PMT ClearPET™ prototype
JF  - 2003 IEEE Nuclear Science Symposium Conference Record, Vol. 5
N2  - The ClearPET™ project is proposed by working groups of the Crystal Clear Collaboration (CCC) to develop a 2nd generation high performance small animal positron emission tomograph (PET). High sensitivity and high spatial resolution is foreseen for the ClearPET™ camera by using a phoswich arrangement combining mixed lutetium yttrium aluminum perovskite (LuYAP:Ce) and lutetium oxyorthosilicate (LSO) scintillating crystals. Design optimizations for the first photomultiplier tube (PMT) based ClearPET camera are done with a Monte-Carlo simulation package implemented on GEANT3 (CERN, Geneva, Switzerland). A dual-head prototype has been built to test the frontend electronics and was used to validate the implementation of the GEANT3 simulation tool. Multiple simulations were performed following the experimental protocols to measure the intrinsic resolution and the sensitivity profile in axial and radial direction. Including a mean energy resolution of about 27.0% the simulated intrinsic resolution is about (1.41±0.11)mm compared to the measured of (1.48±0.06)mm. The simulated sensitivity profiles show a mean square deviation of 12.6% in axial direction and 3.6% in radial direction. Satisfactorily these results are representative for all designs and confirm the scanner geometry.
Y1  - 2004
SN  - 1082-3654
SP  - 3053
EP  - 3056
ER  -