PURPOSE: To assess uncertainties in the definition of the clinical target volume (CTV) for @entity1 scheduled for primary radiotherapy of @entity189 . METHODS AND MATERIALS: Seven physicians (five radiation oncologists and two gynaecologists) independently contoured the CTVs for three @entity1 . All observers were provided with the same clinical information. CTVs were entered directly in the treatment planning system. Differences were analysed qualitatively and quantitatively. RESULTS: The qualitative analysis revealed a good agreement by all observers on anatomical structures identified to be at risk for @entity5 spread. Quantitatively, however, a large interobserver variability was found. The ratio between largest and smallest volumes ranged between 3.6 and 4.9 for all observers (3.6-4.9 for the radiation oncologists, 1.3-2.8 for the gynaecologists). The median three-dimensional difference in gravity centres ranged between 10.9 and 26.3mm for the respective @entity1 . The ratio of common volumes to encompassing volumes ranged between 0.11 and 0.13 for the radiation oncologists, and between 0.30 and 0.57 for the gynaecologists. CONCLUSIONS: Although there was a good consistency in outlined anatomical structures, for the radiation therapy of @entity189 of the uterine cervix a large interobserver variability in CTV delineation concerning the magnitude and relative location of volumes was observed. Compared to other factors, e.g. set-up and organ motion, interobserver variability in CTV definition seems to have the highest impact on the geometrical accuracy in the radiotherapy of this @entity5 entity.

XXXX : differences in the delineation of the clinical target volume. A comparison between gynaecologic and radiation oncologists.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumour'] @entity189 :: ('MESH:D002277', 'Disease') :: ['carcinomas', 'cervix carcinoma']
@entity189 :: (MESH:D002277,Disease) :: ['Conformal radiotherapy planning of cervix carcinoma']
