Euromedim 2006 :1st European Conference on Molecular Imaging Technology

Detector normalization and scatter correction for the jPET-D4: a 4-layer depth-of-interaction PET scanner

9 May 2006, 14:00

1h

Palais du Pharo, Marseille

poster • Image reconstruction and processing Poster Session :Simulation, Modeling, Reconstruction

Speaker

Dr Keishi Kitamura (Shimadzu Corporation)

Description

The jPET-D4 is a brain PET scanner composed of 4-layer depth-of-interaction (DOI) detectors with a large number of GSO crystals, which achieves both high spatial resolution and high scanner sensitivity. Since the sensitivity of each crystal elements highly depends on the depth of DOI layers and the energy of an incident gamma ray, it is difficult to estimate normalization factors and scatter components with high statistical accuracy. In this work, we implemented a hybrid scatter correction method combined with component-based normalization, which estimates scatter components with a dual energy acquisition through an estimation of trues from an upper energy window using a convolution subtraction method. In order to reduce statistical noise in sinograms, the implemented scheme uses the DOI compression (DOIC) method, which combines deep pairs of DOI layers into the nearest shallow pairs of DOI layers with natural detector samplings. Since the compressed data preserve block detector configuration as if acquired with ‘virtual’ detectors having a high stopping power for the gamma rays, the correction methods can be applied directly to DOIC sinograms. To investigate the performance, we compare the DOIC based correction with the conventional non-DOI correction using phantom measurements of the jPET-D4. The results indicate that the quality of normalization and scatter correction of the DOIC data is almost the same as those of the non-DOI data, while the statistical error in uncompressed DOI data increases rapidly with the depth of DOI layers. The proposed method also allows us to improve computational efficiency and to reduce acquisition time and storage size for normalization data even for multi-layer DOI detectors.