“…Efforts by Hasegawa and colleagues in the late 1980s paved the way for combined SPECT/CT (in 1996) and PET/CT (in 1998) platforms for human imaging that generally facilitated sequential data acquisitions with high spatial correspondence of the multimodality data (Townsend, 2008). Simultaneous PET/MRI is now possible in humans (Catana et al, 2008;Herzog et al, 2011;Schlemmer et al, 2008) after an extensive technical development period that includes early study of magnetic field effects on positron range (Christensen et al, 1995;Iida et al, 1986) and subsequent development of a preclinical simultaneous PET/MR scanner by Cherry and colleagues (Townsend, 2008, for review). In the preclinical animal imaging arena, multimodality molecular imaging has been widely applied with dual and triple modality options (i.e., PET/MR, PET/SPECT/CT, or SPECT/CT/optical) possible or under development (Goorden and Beekman, 2010;Stout and Zaidi, 2009;Wehrl et al, 2009).…”