ESTRO course on Image Guided Radiotherapy in Clinical Practice 2018

Observer variation in the neck



18 observers

– MCA, AvL, VUMC, ARTI, RISO, MST, MCH,

UMCG, RIF, MAASTRO, UMCN, DDHK,

UMCU, Leuven, Middelheim,



1 patient



Delineation according to guidelines as

published by Gregoire et al

– R&O 2003

Prevertebral Level 1-2

Gregoire et al 2003 R&O

2 top

2 mid

2 bottom

Overall observer variation (SD)

Anatomical regions

Lymph nodes

GTV CT

GTV CT MRI

SD CT (mm)

All regions

3.6

4.4

3.3

4.4

3.4

2.7

Dorsal

3.7

3.6

2.7

Caudal

4.6

7.7

3.5

Cranial

3.8

L-R

3.0

Parotid

4.0

Vertebrae

2.2

Vessels

2.3