Fig. 5

Schematic illustration of the differences between conventional PET (top) and TOF-PET (bottom). In conventional PET, there is equal probability (illustrated by the blue bars) for the recorded event along the LOR (a). In TOF-PET, the time difference between the arrival of the two annihilation photons, is used to create a probability distribution locating the recorded event at distance ∆ from the axis of the tomography (dashed line). A timing resolution of 600 ps, for example, results in a FWHM of about 9 cm. The probability distribution and knowledge about the timing resolution of the detector system can be incorporated into the reconstruction process, illustrated here for a single projection (b). c Reconstructed PET emission images illustrate the improved SNR in TOF-PET for a patient with BMI 24