A new approach to the measurement of resolution and sampling on a positron emission tomograph

Two technical difficulties underlie the accurate determination of spatial resolution in positron emission tomography (PET): (1) measuring the full-width half-maximum (FWHM) and full-width tenth-maximum (FWTM) from undersampled profiles; (2) measuring axial resolution from multiple reconstructed data sets. To address the first problem, a technique that involves a quadratic estimation of the peak of the profile distribution was developed. This method was compared with the standard technique of Gaussian fitting and was found to be as accurate for constant background distributions. For axial resolution, a second method involving a single scan and imaging of line sources oriented 45 degrees to the axis of the scanner was proposed. Axial FWHM estimations were achieved by deconvolving the values obtained with line spread functions from sources placed parallel to the axis of the scanner. This technique was validated by comparing the results with those obtained by others using a multiple-scan technique on a similar machine