Table 1.

Main specifications of brain PET state of the art systems. The Transaxial Field Of View (TFOV) and Axial Field Of View (AFOV) are reported as well as spatial resolution (in terms of Full Width Half Maximum), sensitivity and the energy window (EW) applied.

	TFOV [mm]	AFOV [mm]	FWHM [mm]	Sens.	EW [keV]
HRRT [18]	312	252	≃2.5	4.3%	350–650
jPET-D4 [19,20,21]	390	260	3	9.82%	400–600
Neuro PET/CT [22]	357	220	3	0.75%	400–650
PET-Hat [23]	280	N.A.	4.2	0.72%	>350
CareMiBrain [24]	256	154	≃1.7	7%	355–664
Hamamatsu [25]	330	201.6	2	2.14%	400–650