Fig. 6.

Scatterplots showing lesion size, SUVmax, and CR increase obtained in 25 patients. Each panel represents a different reconstruction: TOF OSEM with 28 subsets and 2 iterations (a), TOF BSREM with regularization parameter β = 350 (b), 400 (c), 450 (d), 500 (e), and 700 (f). The CR range was limited from − 50 to 50% for clarity. It can be appreciated that with increasing β value, the SUVmax and CR decreases in all lesions. SUV standardized uptake value, SUVmax the average of the hottest 5 voxels in the lesion, CR the percentage increase of the tumor to background ratio of the indicated reconstruction compared to the reference TOF OSEM reconstruction with 2 iterations and 28 subsets. TOF time-of-flight, OSEM ordered subset expectation maximization, BSREM block sequential regularized expectation maximization