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Interobserver delineation variation in lung tumour stereotactic body radiotherapy

Persson, Gitte Fredberg ; Nygaard, D. E. LU ; Hollensen, C. ; Af Rosenschöld, P. Munck LU orcid ; Mouritsen, L. S. ; Due, A. K. ; Berthelsen, A. K. ; Nyman, J. LU ; Markova, E. and Roed, A. P. , et al. (2012) In British Journal of Radiology 85(1017). p.654-660
Abstract

Objectives: In radiotherapy, delineation uncertainties are important as they contribute to systematic errors and can lead to geographical miss of the target. For margin computation, standard deviations (SDs) of all uncertainties must be included as SDs. The aim of this study was to quantify the interobserver delineation variation for stereotactic body radiotherapy (SBRT) of peripheral lung tumours using a cross-sectional study design. Methods: 22 consecutive patients with 26 tumours were included. Positron emission tomography/CT scans were acquired for planning of SBRT. Three oncologists and three radiologists independently delineated the gross tumour volume. The interobserver variation was calculated as a mean of multiple SDs of... (More)

Objectives: In radiotherapy, delineation uncertainties are important as they contribute to systematic errors and can lead to geographical miss of the target. For margin computation, standard deviations (SDs) of all uncertainties must be included as SDs. The aim of this study was to quantify the interobserver delineation variation for stereotactic body radiotherapy (SBRT) of peripheral lung tumours using a cross-sectional study design. Methods: 22 consecutive patients with 26 tumours were included. Positron emission tomography/CT scans were acquired for planning of SBRT. Three oncologists and three radiologists independently delineated the gross tumour volume. The interobserver variation was calculated as a mean of multiple SDs of distances to a reference contour, and calculated for the transversal plane (SD trans) and craniocaudal (CC) direction (SD cc) separately. Concordance indexes and volume deviations were also calculated. Results: Median tumour volume was 13.0 cm 3, ranging from 0.3 to 60.4 cm 3. The mean SD trans was 0.15 cm (SD 0.08 cm) and the overall mean SD cc was 0.26 cm (SD 0.15 cm). Tumours with pleural contact had a significantly larger SD trans than tumours surrounded by lung tissue. Conclusions: The interobserver delineation variation was very small in this systematic cross-sectional analysis, although significantly larger in the CC direction than in the transversal plane, stressing that anisotropic margins should be applied. This study is the first to make a systematic cross-sectional analysis of delineation variation for peripheral lung tumours referred for SBRT, establishing the evidence that interobserver variation is very small for these tumours.

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publishing date
type
Contribution to journal
publication status
published
subject
in
British Journal of Radiology
volume
85
issue
1017
pages
654 - 660
publisher
British Institute of Radiology
external identifiers
  • pmid:22919015
  • scopus:84866084015
ISSN
0007-1285
DOI
10.1259/bjr/76424694
language
English
LU publication?
no
id
eca51e61-a4b0-470e-9dd4-7e6c2747a368
date added to LUP
2023-07-19 17:16:23
date last changed
2024-01-05 03:35:35
@article{eca51e61-a4b0-470e-9dd4-7e6c2747a368,
  abstract     = {{<p>Objectives: In radiotherapy, delineation uncertainties are important as they contribute to systematic errors and can lead to geographical miss of the target. For margin computation, standard deviations (SDs) of all uncertainties must be included as SDs. The aim of this study was to quantify the interobserver delineation variation for stereotactic body radiotherapy (SBRT) of peripheral lung tumours using a cross-sectional study design. Methods: 22 consecutive patients with 26 tumours were included. Positron emission tomography/CT scans were acquired for planning of SBRT. Three oncologists and three radiologists independently delineated the gross tumour volume. The interobserver variation was calculated as a mean of multiple SDs of distances to a reference contour, and calculated for the transversal plane (SD <sub>trans</sub>) and craniocaudal (CC) direction (SD <sub>cc</sub>) separately. Concordance indexes and volume deviations were also calculated. Results: Median tumour volume was 13.0 cm <sup>3</sup>, ranging from 0.3 to 60.4 cm <sup>3</sup>. The mean SD <sub>trans</sub> was 0.15 cm (SD 0.08 cm) and the overall mean SD <sub>cc</sub> was 0.26 cm (SD 0.15 cm). Tumours with pleural contact had a significantly larger SD <sub>trans</sub> than tumours surrounded by lung tissue. Conclusions: The interobserver delineation variation was very small in this systematic cross-sectional analysis, although significantly larger in the CC direction than in the transversal plane, stressing that anisotropic margins should be applied. This study is the first to make a systematic cross-sectional analysis of delineation variation for peripheral lung tumours referred for SBRT, establishing the evidence that interobserver variation is very small for these tumours.</p>}},
  author       = {{Persson, Gitte Fredberg and Nygaard, D. E. and Hollensen, C. and Af Rosenschöld, P. Munck and Mouritsen, L. S. and Due, A. K. and Berthelsen, A. K. and Nyman, J. and Markova, E. and Roed, A. P. and Roed, H. and Korreman, S. and Specht, L.}},
  issn         = {{0007-1285}},
  language     = {{eng}},
  number       = {{1017}},
  pages        = {{654--660}},
  publisher    = {{British Institute of Radiology}},
  series       = {{British Journal of Radiology}},
  title        = {{Interobserver delineation variation in lung tumour stereotactic body radiotherapy}},
  url          = {{http://dx.doi.org/10.1259/bjr/76424694}},
  doi          = {{10.1259/bjr/76424694}},
  volume       = {{85}},
  year         = {{2012}},
}