PET-CT-Based Auto-Contouring in Non-Small-Cell Lung Cancer Correlates With Pathology and Reduces Interobserver Variability in the Delineation of the Primary Tumor and Involved Nodal Volumes

Journal Article · Sun Jul 01 00:00:00 EDT 2007 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2006.12.067· OSTI ID:20951704

Baardwijk, Angela van ^[1]; Bosmans, Geert ^[1]; Boersma, Liesbeth ^[1]; Buijsen, Jeroen ^[1]; Wanders, Stofferinus ^[1]; Hochstenbag, Monique ^[2]; Suylen, Robert-Jan van ^[3]; Dekker, Andre ^[1]; Dehing-Oberije, Cary ^[1]; Houben, Ruud ^[1]; Bentzen, Soren M ^[4]; Kroonenburgh, Marinus van ^[5]; Lambin, Philippe ^[1]; Ruysscher, Dirk de ^[1]

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1. Department of Radiation Oncology (MAASTRO), GROW, University Hospital Maastricht, Maastricht (Netherlands)
2. Department of Pulmonology, University Hospital Maastricht, Maastricht (Netherlands)
3. Department of Pathology, University Hospital Maastricht, Maastricht (Netherlands)
4. Department of Human Oncology, University of Wisconsin, Madison, WI (United States)
5. Department of Nuclear Medicine, University Hospital Maastricht, Maastricht (Netherlands)

Purpose: To compare source-to-background ratio (SBR)-based PET-CT auto-delineation with pathology in non-small-cell lung cancer (NSCLC) and to investigate whether auto-delineation reduces the interobserver variability compared with manual PET-CT-based gross tumor volume (GTV) delineation. Methods and Materials: Source-to-background ratio-based auto-delineation was compared with macroscopic tumor dimensions to assess its validity in 23 tumors. Thereafter, GTVs were delineated manually on 33 PET-CT scans by five observers for the primary tumor (GTV-1) and the involved lymph nodes (GTV-2). The delineation was repeated after 6 months with the auto-contour provided. This contour was edited by the observers. For comparison, the concordance index (CI) was calculated, defined as the ratio of intersection and the union of two volumes (A intersection B)/(A union B). Results: The maximal tumor diameter of the SBR-based auto-contour correlated strongly with the macroscopic diameter of primary tumors (correlation coefficient = 0.90) and was shown to be accurate for involved lymph nodes (sensitivity 67%, specificity 95%). The median auto-contour-based target volumes were smaller than those defined by manual delineation for GTV-1 (31.8 and 34.6 cm{sup 3}, respectively; p = 0.001) and GTV-2 (16.3 and 21.8 cm{sup 3}, respectively; p 0.02). The auto-contour-based method showed higher CIs than the manual method for GTV-1 (0.74 and 0.70 cm{sup 3}, respectively; p < 0.001) and GTV-2 (0.60 and 0.51 cm{sup 3}, respectively; p = 0.11). Conclusion: Source-to-background ratio-based auto-delineation showed a good correlation with pathology, decreased the delineated volumes of the GTVs, and reduced the interobserver variability. Auto-contouring may further improve the quality of target delineation in NSCLC patients.

• OSTI ID: 20951704
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 68, Issue 3; Other Information: DOI: 10.1016/j.ijrobp.2006.12.067; PII: S0360-3016(07)00082-X; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CARCINOMAS
COMPUTERIZED TOMOGRAPHY
LUNGS
LYMPH NODES
PATHOLOGY
PATIENTS
SENSITIVITY
SPECIFICITY