2016_Imaging for Physicists

Attenuation Correction

Probability P 1 detector:

for quant γ 1

to reach a

∫ ⋅ = − ox x dx x ek P )( µ for quant γ 2 : ∫ ⋅ = − x ux dx x e k P )( µ

x O

γ 1

x

1

1

γ 2

Accordingly P 2

x U

2

2

Probability for a coincidence event:

∫ ⋅ ⋅ = ⋅ = − ox ux dx x e kk PP P )( µ

2 1

2 1

tot

ESTRO Teaching Course Advanced Imaging: PET – Reconstruction, Contouring Accurate attenuation correction is possible if the line integral can be obtained from a transmission measurement. CT is used for attenuation correction! ∫ o u x x

dxx )( µ

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