Change search
ReferencesLink to record
Permanent link

Direct link
Assessment of organs-at-risk contouring practices in radiosurgery institutions around the world - The first initiative of the OAR Standardization Working Group
Stockholm University, Faculty of Science, Department of Physics. Karolinska Institutet, Sweden.
University of Toronto, Canada.
Tohoku University School of Medicine, Japan.ORCID iD: 0000-0001-8880-2865
Hygeia Hospital, Greece.
Show others and affiliations
2016 (English)In: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, Vol. 121, no 2, 180-186 p.Article in journal (Refereed) Published
Abstract [en]

Materials and methods

Imaging datasets for typical lesions (cavernous sinus meningioma, vestibular schwannoma, pituitary adenoma) treated with Leksell Gamma Knife Perfexion were circulated to 12 centers. Observers were asked to contour the target and OARs as per their standard clinical practice. The analyzed parameters were the intersection (AV100), union volumes (AV100/N) and the 50% agreement volume (AV50). The ratio of AV100 and AV100/N (the Agreement Volume Index, AVI) was used as a measure of agreement level together with a generalized conformity index (CIgen) and a pairwise averaged conformity index (CIpairs). The maximum doses were also determined.


Results showed a wide variability in terminology, choice of structures contoured and in the size and shape of the contoured structures. The highest variability was observed for the left and right optic tract for cavernous sinus meningioma where the AV100 was zero. The highest consistency was observed for the right optic nerve in the cavernous sinus case followed by the cochlea for the vestibular schwannoma case for which the AVI was still only 0.13 and 0.054, respectively. Corresponding results for the CIgen and CIpairs also showed the highest variability for the right optic tract and the highest consistency in contours for the right optic nerve, both in the cavernous sinus meningioma case.


The results quantify the large variability in OAR contouring in clinical practice across Gamma Knife radiosurgery centers with respect to the choice of OARs to be contoured, nomenclature and size and shape of OARs. This motivates future effort to standardize practices to enable more effective collaboration.

Place, publisher, year, edition, pages
2016. Vol. 121, no 2, 180-186 p.
Keyword [en]
Optic nerve, Chiasm, Cochlea, Stereotactic radiosurgery, Inter-observer variability
National Category
Cancer and Oncology
Research subject
Medical Radiation Physics
URN: urn:nbn:se:su:diva-135331DOI: 10.1016/j.radonc.2016.10.014ISI: 000390517600002PubMedID: 27816408OAI: diva2:1044574
Available from: 2016-11-03 Created: 2016-11-03 Last updated: 2017-02-07Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Sandström, HelenaJokura, HidefumiToma-Dasu, Iuliana
By organisation
Department of Physics
In the same journal
Radiotherapy and Oncology
Cancer and Oncology

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 37 hits
ReferencesLink to record
Permanent link

Direct link