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Gradient-based delineation of the primary GTV on FDG-PET in non-small cell lung cancer: A comparison with threshold-based approaches, CT and surgical specimens
- Source :
- Radiotherapy and Oncology. 98:117-125
- Publication Year :
- 2011
- Publisher :
- Elsevier BV, 2011.
-
Abstract
- PURPOSE: The aim of this study was to validate a gradient-based segmentation method for GTV delineation on FDG-PET in NSCLC through surgical specimen, in comparison with threshold-based approaches and CT. MATERIALS AND METHODS: Ten patients with stage I-II NSCLC were prospectively enrolled. Before lobectomy, all patients underwent contrast enhanced CT and gated FDG-PET. Next, the surgical specimen was removed, inflated with gelatin, frozen and sliced. The digitized slices were used to reconstruct the 3D macroscopic specimen. GTVs were manually delineated on the macroscopic specimen and on CT images. GTVs were automatically segmented on PET images using a gradient-based method, a source to background ratio method and fixed threshold values at 40% and 50% of SUV(max). All images were finally registered. Analyses of raw volumes and logarithmic differences between GTVs and GTV(macro) were performed on all patients and on a subgroup excluding the poorly defined tumors. A matching analysis between the different GTVs was also conducted using Dice's similarity index. RESULTS: Considering all patients, both lung and mediastinal windowed CT overestimated the macroscopy, while FDG-PET provided closer values. Among various PET segmentation methods, the gradient-based technique best estimated the true tumor volume. When analysis was restricted to well defined tumors without lung fibrosis or atelectasis, the mediastinal windowed CT accurately assessed the macroscopic specimen. Finally, the matching analysis did not reveal significant difference between the different imaging modalities. CONCLUSIONS: FDG-PET improved the GTV definition in NSCLC including when the primary tumor was surrounded by modifications of the lung parenchyma. In this context, the gradient-based method outperformed the threshold-based ones in terms of accuracy and robustness. In other cases, the conventional mediastinal windowed CT remained appropriate.
- Subjects :
- Male
medicine.medical_specialty
Lung Neoplasms
Atelectasis
Context (language use)
Fluorodeoxyglucose F18
Carcinoma, Non-Small-Cell Lung
medicine
Humans
Radiology, Nuclear Medicine and imaging
Prospective Studies
Stage (cooking)
Aged
Aged, 80 and over
Fluorodeoxyglucose
medicine.diagnostic_test
business.industry
Hematology
Middle Aged
medicine.disease
Primary tumor
Oncology
Positron emission tomography
Positron-Emission Tomography
Female
Radiology
Tomography
Radiopharmaceuticals
Tomography, X-Ray Computed
Nuclear medicine
business
Emission computed tomography
medicine.drug
Subjects
Details
- ISSN :
- 01678140
- Volume :
- 98
- Database :
- OpenAIRE
- Journal :
- Radiotherapy and Oncology
- Accession number :
- edsair.doi.dedup.....1cb1b174257754a11f0714edb87e2da4
- Full Text :
- https://doi.org/10.1016/j.radonc.2010.10.006