Euromedim 2006 :1st European Conference on Molecular Imaging Technology

Status of the optimized ClearPET(tm) Neuro scanner

10 May 2006, 09:30

15m

Palais du Pharo, Marseille

oral S1-S2 Small animal imaging

Speaker

Dr Karl Ziemons (Forschungszentrum Juelich)

Description

The ClearPET(tm) Neuro scanner, a dedicated high performance small animal PET scanner at Forschungszentrum Jülich GmbH, has been developed as a device for molecular neuroimaging in rodents and non-human primates under physiological conditions. Innovative features developed within the Crystal Clear Collaboration (CCC) have been implemented in particular with regard to crystal material and electronics which allow achieving both high resolution and high sensitivity. Each of the 80 detector modules consist of a crystal matrix with two crystal materials, LSO and LuYAP:Ce, combined in a phoswich arrangement which are coupled to a multi-channel PMT. The gantry allows rotation of the detector modules as well as tilting by 90 degrees to measure non-human primates in an upright sitting position. The opening diameter of the ring is variable between 130mm and 300mm, the axial detector length is 110mm. The reconstruction of the images has been performed by using the 3D-OSEM algorithm based on the STIR library (Software for Tomografic Image Reconstruction, http://stir.irsl.org <http://stir.irsl.org/> ). A suitable normalization procedure takes account of the unconventional geometry. Already the very first measurements of phantoms and also with rats confirmed the high performance of the scanner and showed its capabilities for in vivo small animal scanning. Based on these preliminary results during the first testing periode the ClearPET(tm) Neuro System has been modified to optimize specific properties like the DOI, the detector positions and the maximum count rate. For the new assembly the crystal matrices have been repackaged in firmer and more compact blocks with BaSO4 as reflector material between crystals. The axial distance between the detector blocks within the detector cassettes has been reduced and the shift between every other cassette has been changed. The new positioning of the detectors was implemented to achieve a higher packaging density and a distance between the detector blocks which is an integer multiple of the slice width. To improve the count rate performance further a new file server is implemented which will allow a maximum count rate of 9 Mcps single events. We present the current status of the ClearPET Neuro scanner and elaborate on the effects of the recently implemented modifications.