PET in radiotherapyGradient-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
Section snippets
Patient selection
Ten patients (mean age 66 years; range 54–85) with histologically proven NSCLC stage I–II were prospectively enrolled in this study between October 2008 and February 2010. From these 10 patients, 6 had squamous cell carcinoma (SCC) and 4 had an adenocarcinoma (ADC). All patients were exclusively treated by lobectomy, excluding thus atypical resections and pneumonectomy. One patient had pre-operative chemotherapy. The patients and their primary tumor characteristics are summarized in Table 1.
Results
The GTVs delineated with the considered imaging modalities are reported in Table 2. The mean and standard deviations of the raw GTVs are provided as well. As detailed in the statistical analysis section, they were computed after logarithmic transformation of the volumes in order to process data distributions that were closer to normality (Fig. 1). Means and standard deviations of transformed volumes are illustrated in Fig. 1 with error bars (mean ± 1SD).
With all patients taken into consideration,
Discussion
Overall, we showed that FDG-PET outperformed CT for the delineation of primary tumor volumes in NSCLC, as previously observed in HNSCC patients [44]. We also confirmed the superiority of the gradient-based segmentation, compared to usual threshold-based delineation, both in terms of raw volumes and logarithmically transformed ones. However, the added value of FDG-PET was more pronounced in cases of tumors surrounded by densifications of the lung parenchyma (atelectasis, BOOP). In other cases,
Acknowledgements
This research program was supported by a grant from the Belgian National Fund for Scientific Research (FNRS Télévie, Grant No. 7.4537.09). Xavier Geets is a postdoctoral researcher partially funded by the FNRS (Grant No. 3.4600.08). John A. Lee is a research associate funded by the FNRS.
References (69)
- et al.
Can we optimize chemo-radiation and surgery in locally advanced stage III non-small cell lung cancer based on evidence from randomized clinical trials? A hypothesis-generating study
Radiother Oncol
(2009) - et al.
Radiation dose prescription for non-small-cell lung cancer according to normal tissue dose constraints: an in silico clinical trial
Int J Radiat Oncol Biol Phys
(2008) - et al.
Individualized radical radiotherapy of non-small-cell lung cancer based on normal tissue dose constraints: a feasibility study
Int J Radiat Oncol Biol Phys
(2008) - et al.
Clinical implications of defining the gross tumor volume with combination of CT and 18FDG-positron emission tomography in non-small-cell lung cancer
Int J Radiat Oncol Biol Phys
(2007) - et al.
Impact of computed tomography and 18F-deoxyglucose coincidence detection emission tomography image fusion for optimization of conformal radiotherapy in non-small-cell lung cancer
Int J Radiat Oncol Biol Phys
(2005) - et al.
The impact of (18)FDG-PET on target and critical organs in CT-based treatment planning of patients with poorly defined non-small-cell lung carcinoma: a prospective study
Int J Radiat Oncol Biol Phys
(2002) - et al.
Increased therapeutic ratio by 18FDG-PET CT planning in patients with clinical CT stage N2–N3M0 non-small-cell lung cancer: a modeling study
Int J Radiat Oncol Biol Phys
(2005) - et al.
CT and (18)F-deoxyglucose (FDG) image fusion for optimization of conformal radiotherapy of lung cancers
Int J Radiat Oncol Biol Phys
(2001) - et al.
Radiotherapy treatment planning for patients with non-small cell lung cancer using positron emission tomography (PET)
Radiother Oncol
(2002) - et al.
18F-deoxyglucose positron emission tomography (FDG-PET) for the planning of radiotherapy in lung cancer: high impact in patients with atelectasis
Int J Radiat Oncol Biol Phys
(1999)