A geometrical correction method for radioactive intensity image reconstruction in tomographic gamma scanning

Zhe Liu; Li Zhang; Xiaolei Jiang

doi:10.1117/12.928444

17 October 2012 A geometrical correction method for radioactive intensity image reconstruction in tomographic gamma scanning

Zhe Liu, Li Zhang, Xiaolei Jiang

Author Affiliations +

Proceedings Volume 8506, Developments in X-Ray Tomography VIII; 85061L (2012) https://doi.org/10.1117/12.928444
Event: SPIE Optical Engineering + Applications, 2012, San Diego, California, United States

Abstract

Tomographic Gamma Scanning (TGS) is one of the non-destructive analysis technologies based on the principles of Emission Computed Tomography (ECT). Dedicated on imaging of the Gamma ray emission, TGS reveals radioactivity distributions for different radionuclides inside target objects such as nuclear waste barrels. Due to the special characteristics of TGS imaging geometry, namely, the relatively larger detector cell size and more remarkable view change in the imaging region, the line integral projection model widely used in ECT problems is no longer applicable for the radioactive intensity image reconstruction in TGS. The alternative Monte-Carlo based methods which calculate the detection efficiency at every detecting position for each voxel are effective and accurate, however time consuming. In this paper, we consider the geometrical detection efficiency of detector that is dependent on the detector-voxel relative position independently from the intrinsic detection efficiency. Further, a new geometrical correction method is proposed, where the voxel volume within the detector view is applied as the projection weight substituting the track length used in line integral model. And the geometrical detection efficiencies at different positions are analytically expressed by the volume integral on the voxel of geometrical point-source response function of the detector. Numerical simulations are taken and discussions are provided. The results show that the proposed method reduces the reconstruction errors compared to the line integral projection method while gaining better calculating efficiency and flexibility than former Monte-Carlo methods.

Citation Download Citation

Zhe Liu, Li Zhang, and Xiaolei Jiang "A geometrical correction method for radioactive intensity image reconstruction in tomographic gamma scanning", Proc. SPIE 8506, Developments in X-Ray Tomography VIII, 85061L (17 October 2012); https://doi.org/10.1117/12.928444

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