Ae. Saarnak et al., Inter-observer variation in delineation of bladder and rectum contours forbrachytherapy of cervical cancer, RADIOTH ONC, 56(1), 2000, pp. 37-42
Citations number
20
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Onconogenesis & Cancer Research
Background and purpose: In 3D treatment planning of low dose rate brachythe
rapy of cervical carcinoma the dose in bladder and rectum can be estimated
from dose-volume histograms (DVHs). In this study, the influence of inter-o
bserver variation in delineation of bladder and rectum on DVHs and dose at
specific bladder and rectum points was investigated.
Materials and methods: Three observers delineated bladder and rectum on axi
al CT images of ten patients. The highest minimum dose in bladder and rectu
m was determined for, respectively, 2 cm(3) (D-2) and 5 cm(3) (D-5)r as wel
l as the dose at specific points placed on the bladder and rectum wall.
Results: The inter-observer variation in D-2 was 10% (1 average relative SD
) in bladder and 11% (1 SD) in rectum. In D-2 the variation was 8% (1 SD) i
n bladder and 11% in rectum. The variation in the bladder point was 13% (1
SD) and in the rectum point 11% (1 SD). Differences in delineation among th
e observers were caused by unclear organ boundaries on the CT images.
Conclusions: Taking the inter-observer variation caused by delineation diff
erences into account, dose in bladder and rectum can be determined within a
n accuracy of about 10% (1 SD). (C) 2000 Elsevier Science Ireland Ltd. All
rights reserved.