Rotating positron tomographs revisited.
We have compared the performance of a PET scanner comprising two rotating arrays of detectors with that of the more conventional stationary-ring design. The same total number of detectors was used in each, and neither scanner had septa. For brain imaging, we find that the noise-equivalent count rate is greater for the rotating arrays by a factor of two. Rotating arrays have a sensitivity profile that peaks in the centre of the field of view, both axially and transaxially. In the transaxial plane, this effect offsets to a certain extent the decrease in the number of photons detected towards the centre of the brain due to self-absorption. We have also compared the performance of a rotating scanner to that of a full-ring scanner with the same number of rings. We find that a full-ring scanner with an axial extent of 16.2 cm (24 rings) is a factor of 3.5 more sensitive than a rotating scanner with 40% of the detectors and the same axial extent.
Townsend
D
D
Division of Nuclear Medicine, Geneva University Hospital, Geneva, Switzerland.
Byars
L
L
Defriset
M
M
Geissbuhler
A
A
Nutt
R
R
D001921:Brain / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D015233:Models, Statistical; D009068:Movement; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods*; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014055:Tomography, Emission-Computed / Q000379:methods*