Non-uniformity measurements in PET.
To gain practical experience with the procedures suggested by the EEC task group on performance evaluation of positron tomographs, the non-uniformity of the Scanditronix PC 2048-7WB positron tomograph was measured. The test was performed using both a cylindrical head phantom and the EEC body phantom. According to the recommendation of the task group, 2 million counts were collected in each emission scan as a standard. As to be expected, non-uniformity decreased when more counts were collected or a wider reconstruction filter was used. Non-uniformity increased when going from the head phantom to the body phantom leaving all parameters unchanged. It was concluded that this effect was caused by increased noise due to the larger attenuation lengths but not to attenuation correction. The preliminary results of this study show that counting statistics dominates non-uniformity in the count range of about 2 million counts per image. Measured non-uniformity values are in the range of +/- 30%.
Ostertag
H J
HJ
Deutsches Krebsforschungszentrum, Institut für Radiologie und Pathophysiologie, Heidelberg, Germany.
Doll
J
J
Kübler
W K
WK
D004867:Equipment Design; D005060:Europe; D005069:Evaluation Studies as Topic; D014055:Tomography, Emission-Computed / Q000295:instrumentation*