Effect of tissue density on PET spatial resolution in magnetic environment Chong Li, Xingzhong Cao, Fuyan Liu, Peng Zhang, Zhiming Zhang, Long Wei and Baoyi Wang Eur. Phys. J. Plus, 135 1 (2020) 118 Published online: 23 January 2020 DOI: 10.1140/epjp/s13360-020-00198-x