Fig. 5.

Example dataset showing axial PET images of the pelvic frame. The reconstructions are TOF OSEM with 28 subsets and 2 iterations (a); TOF BSREM with regularization parameter β = 400 (b), 500 (c), 700 (d), 900 (e), and 1200 (f). All images have SUV scale 0–5 g/ml. Red arrow indicates the same lymph node lesion as in Fig. 2. It can be appreciated that the background noise decreases with increasing β values. It can also be appreciated that the SUV of the lymph node lesion decreases with increasing β values; however, the lesion is still clearly detectable even with β = 1200 (f). SUV standardized uptake value, TOF time-of-flight, OSEM ordered subset expectation maximization, BSREM block sequential regularized expectation maximization