Use of a magnetic field to increase the spatial resolution of positron emission tomography

Abstract

Detector geometry, spatial sampling, and more fundamentally, positron range and noncollinearity of annihilation photon emission define Positron Emission Tomography (PET) spatial resolution. In this paper, a strong magnetic field is used to constrain positron travel transverse to the field. Measurement of the spread function from a 500 microns diameter 68Ga impregnated resin bead shows a squeezing of the full width at half maximum (FWHM) by a factor of 1.0, 1.22, 1.42, and 2.05, at 0, 4.0, 5.0, and 9.4 Tesla, respectively. The full width at tenth maximum (FWTM) decreases by a factor of 1.0, 1.73, 2.09, and 3.20, at 0, 4.0, 5.0, and 9.0 Tesla, respectively. Acquiring a PET image in a magnetic field should significantly reduce resolution loss due to positron range.