Using a stimulated parametric down-conversion process combined with a conventional detector, we theoretically propose a scheme to realize the stimulated emission-based detector, and investigate the antinormalty ordere...Using a stimulated parametric down-conversion process combined with a conventional detector, we theoretically propose a scheme to realize the stimulated emission-based detector, and investigate the antinormalty ordered correlation function and Fano factor for the coherent field based on it. Such a detection has advantages over the normally ordered one especially when the intensity of the field is weak.展开更多
Scatter correction in single photon emission computed tomography （SPECT） has been focused on either using multiple-window acquisition technique or the scatter modeling technique in iterative image reconstruction. We...Scatter correction in single photon emission computed tomography （SPECT） has been focused on either using multiple-window acquisition technique or the scatter modeling technique in iterative image reconstruction. We propose a technique that uses ：only the emission data for scatter correction in SPECT. We assume that the scatter data can be approximated by convolving the primary data with a scatter kernel followed by the normalization using the scatter-to-primary ratio （SPR）, Since the emission data is the superposition of the primary data and the scatter data, the convolution normalization process approximately results in the sum of the scatter data and a convolved version of scatter data with the kernel. By applying a proper scaling factor, we can make the estimation approximately equal to or less than the scatter data anywhere in the projection domain. Phantom and patient cardiac SPECT studies show that using the proposed emission-based scatter estimation can effectively reduce the scatter-introduced background in the reconstructed images. And additionally, the computational time for scatter correction is negligible as compared to no scatter correction in iterative image reconstruction.展开更多
基金Project supported in part by the National Natural Science Foundation of China (Grant Nos. 10774096 and 60708010)the National Basic Research Program of China (Grant No. 2006CB921101)the Research Fund for the Returned Overseas Chinese Scholars of Shanxi Province,China (Grant No. 200713)
文摘Using a stimulated parametric down-conversion process combined with a conventional detector, we theoretically propose a scheme to realize the stimulated emission-based detector, and investigate the antinormalty ordered correlation function and Fano factor for the coherent field based on it. Such a detection has advantages over the normally ordered one especially when the intensity of the field is weak.
文摘Scatter correction in single photon emission computed tomography （SPECT） has been focused on either using multiple-window acquisition technique or the scatter modeling technique in iterative image reconstruction. We propose a technique that uses ：only the emission data for scatter correction in SPECT. We assume that the scatter data can be approximated by convolving the primary data with a scatter kernel followed by the normalization using the scatter-to-primary ratio （SPR）, Since the emission data is the superposition of the primary data and the scatter data, the convolution normalization process approximately results in the sum of the scatter data and a convolved version of scatter data with the kernel. By applying a proper scaling factor, we can make the estimation approximately equal to or less than the scatter data anywhere in the projection domain. Phantom and patient cardiac SPECT studies show that using the proposed emission-based scatter estimation can effectively reduce the scatter-introduced background in the reconstructed images. And additionally, the computational time for scatter correction is negligible as compared to no scatter correction in iterative image reconstruction.
