| dc.description.abstract | This study simulates the pinhole tunneling effect of the single-photon emission microscope (SPEM) and establishes the imaging system matrix from the simulated point response functions. The system configuration of SPEM includes a pinhole collimator, a thallium-doped cesium iodide crystal (CsI(Tl)), an electron multiplying charge-coupled device (EMCCD), and an electrostatic de-magnifier tube (DM tube). In simulation of pinhole tunneling effect, we have to first establish the pinhole surface equation to identify whether the pinhole tunneling effect will occur when a gamma ray is incident onto the pinhole plane. We also use the three-point collinear model to establish the relationship between the object space, the pinhole plane, and the detector plane. Then, we perform the forward projections of point sources, apply Gaussian parameterization to the projected blur functions and establish the imaging model.
The imaging model includes the flux model, width model and principal angle model. By using the established imaging model and the three-point collinear model, we can build the imaging system matrix. Finally, we use the ordered subset expectation maximization (OSEM) to reconstruct 3D object images with target forward projection images and the system matrix. The image reconstruction results validate the established pinhole tunneling model and imaging system matrix. We anticipate this modeling procedure along with the sampling completeness analysis can aid in pinhole pattern design.
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