Dosimetric impact of interobserver variability in MRI-based delineation for cervical cancer brachytherapy

作者：Hellebust Taran Paulsen^*; Tanderup Kari; Lervag Christoffer; Fidarova Elena; Berger Daniel; Malinen Eirik; Poetter Richard; Petric Primoz

来源：Radiotherapy and Oncology, 2013, 107(1): 13-19.

DOI：10.1016/j.radonc.2012.12.017

• Brachytherapy
• Cervical cancer
• Interobserver variability

Purpose and background: To study the dosimetric impact of interobserver delineation variability (IODV) in MRI-based cervical cancer brachytherapy. %26lt;br%26gt;Materials and methods: MR images of six patients were distributed to 10 experienced observers worldwide. They were asked to delineate the target volumes and the organs at risk (OARs) for each patient. Two types of reference contours were created (Expert Consensus - EC and Simultaneous Truth and Performance Level Estimation - STAPLE). Optimised plans based on both EC- and STAPLE-contours were prepared. These plans were transferred to each of the observer contour sets and the resulting DVH parameters (D-90 and D-2cc) were calculated. For each patient the standard deviation (SD) for the 10 observers was calculated. %26lt;br%26gt;Results: A mean relative SD of 8-10% was found for GTV and High Risk CTV (HR-CTV) D-90 analysing one single fraction. For rectum and bladder the mean relative SD for D-2cc was 5-8% while sigmoid was at 11%. For the whole treatment the IODV in HR-CTV caused an uncertainty of +/- 5 Gy(alpha/beta=10)(1SD). The corresponding figure for OARs was +/- 2-3 Gy(alpha/beta=3). The results were not sensitive as to which structure set was used for the optimisation. %26lt;br%26gt;Conclusions: For the target volumes the dosimetric impact of IODV was smallest for the GTV and HR-CTV, while IODV had an even smaller impact on the bladder and rectum.

• 出版日期2013-4