3D imaging of geometrical structure and defect location of inner cavity in aviation devices by positron injection

摘要

Aviation devices such as aero powertrain, hydraulic system are usually with inner cavity structure which is relatively complex. One of the most important challenges are how to determine the spatial geometrical structure and defect in the inner cavity. A 3D imaging method of interior and defect in inner cavity by positron injection is presented on the basis of positron annihilation theory in this paper. Low energy radionuclide is injected into inner cavity in which radionuclide produce positron. PET records the amount of γ photons produced by positron annihilation. Then the maximum likelihood estimation model is introduced and by solving which a 2D slice image sequence is obtained by Ordered Subset Expectation Maximization algorithm (OSEM). At last, a 3D image is reconstructed by the 2D slice image sequence and the 3D image is used to analyze the spatial geometrical structure and defect of inner cavity and thus a new method for the analysis of spatial geometrical structure and defect of inner cavity in aviation devices is generated.