Characterization of tomographic sampling in Hybrid PET using the Fourier crosstalk matrix

Hybrid positron emission tomography (PET) cameras can be used to measure the distribution of positron emitting radionuclides. An important system parameter for Hybrid PET is the appropriate tomographic sampling requirements. In this paper, a previously developed theoretical formulation for quantifying sampling in continuous-to-discrete tomographic systems, termed the "crosstalk matrix," is used to provide information on the recoverability of the Fourier coefficients that represent the continuous object. In addition, the crosstalk matrix can be related to image quality assessment. Here, we use the crosstalk matrix to evaluate tomographic sampling for Hybrid PET systems. Dual- and triple-head systems were compared, with emphasis placed on studying how system performance changes as the number of gantry stops is increased, and as the line-of-response acceptance angle is reduced. Examination of the crosstalk matrix, as well as figures-of-merit measuring task performance that are computed using the crosstalk matrix, show that increasing angular sampling improves Fourier coefficient recoverability and reduces aliasing.