626910.fig.001a
(a)
626910.fig.001b
(b)
626910.fig.001c
(c)
Figure 1: Comparison of positron emission tomography (PET) and single-photon emission computed tomography (SPECT). (a) Schematic representation of the principle behind PET, (b) schematic representation of the principle behind SPECT, and (c) comparison between PET and SPECT.