Imaging for Physicists

Count Rate Performance  Ratio Trues/Randoms unbalanced for high Activities  Processing of detected photons takes finite time  Noise Equivalent Count Rate: T 2

T : trues S : scattered R : randoms f : rel. area of object on proj. surface

NECR

=

2 ++

fR ST

Count rate curves for true, random and multiple coincidences. Derived curves for expected and noise equivalent count rate [2]. Data recorded on a CTI ECAT 953B PET

Maximum image quality

Low image contrast

using a 11 C-filled cylinder in water.

Noisy image

30

ESTRO Teaching Course Advanced Imaging: PET – Basic Principles