1. The problem statement, all variables and given/known data Why does PET scanner use positron emitters? 1-positrons have more penetrating power than electrons 2-positron emitting isotopes are cheap and widely available 3-the location of emission can be located better because a pair of gamma rays get emitted from the body 4-positron radiation is more highly absorbed by cancer tumours, providing contrast in images one or more can be correct. 2. Relevant equations 3. The attempt at a solution Well I believe it should 3 be the correct solution. But I'm not entirely sure.