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Random Correction
ESTRO Teaching Course Advanced Imaging: PET – Reconstruction, Contouring
3
Randoms:
Correction Methods:
Tail Fitting
●
Estimate random distribution in the object
by fitting the tails outside the object
Estimation from Single Rates
●
Direct determination from single rates
N
a
and
N
b
Delayed Coincidence Channel Estimation
●
Data stream containing signals from one channel is delayed for
several times the coincidence window
●
Removal of all annihilation events
●
Any coincidences detected are random
●
Subtraction from coincidences in the prompt channel
2
2
N NN R
b a
ab
∝ ⋅
=
τ