Physical characteristics of the ECAT 953B/31: A new high resolution brain positron tomograph
IEEE Trans. Med. Imaging. 1991-01-01; 10(4): 499-504
Lire sur PubMed
1. IEEE Trans Med Imaging. 1991;10(4):499-504.
Physical characteristics of the ECAT 953B/31: a new high resolution brain
Mazoyer B(1), Trebossen R, Deutch R, Casey M, Blohm K.
(1)Service Hospitalier Frederic Joliot, CEA, Orsay.
A high spatial resolution brain positron tomograph, the ECAT 953B/31, is
presented. The machine consists of two 76.5 cm diameter rings (patient port
diameter: 36 cm) made of 24 8×8 BGO detector blocks each, each block being
coupled to four 1 in(2) Hammamatsu phototubes. The machine has 15 9 cmx1 mm
motorized removable septa, which allows reconstruction of 31 slices 3.375 mm
apart. The transaxial resolution (FWHM) in the reconstructed image (with
wobbling) is 4.5 mm at center, 5.2 mm (tangential) and 5.6 mm at 10 cm from
center. With septa out of the field of view (FOV), the axial resolution degrades
to 5.5 mm a center and 6.3 mm at 10 cm from center. At 1 muCi/cc with a 250 keV
threshold and a 12 ns coincidence window, the sensitivity is 146100 true events,
the ratio of randoms to trues is 0.10, the scatter fraction is 17% and the
dead-time losses are 30%. With septa out of the FOV, the sensitivity is increased
by a factor 3.6, while the scatter fraction reaches 0.9. Images obtained with (18
)F-DG and H(2)(15)O in human brains and (18 )F-DOPA in a baboon brain demonstrate
that the ECAT 953B/31 will be suitable for high resolution and for low count rate