1. A method for positron emission tomography, comprising the following steps: a) two photons are emitted in opposite directions by an annihilation event in a sample; b) at least two of a plurality of detectors arranged around the sample are prompted to output a signal by the two photons; c) a signal line on which the event may have taken place is determined from the location of the detectors which have output a signal; and d) this signal line is evaluated in the tomographic reconstruction of the sample, wherein prior to the tomographic reconstruction of the sample, for each event a plurality of signal lines are determined, the plurality of signal lines then being evaluated in the tomographic reconstruction of the sample.