Impact of computed tomography and 18F-deoxyglucose coincidence detection emission tomography image fusion for optimization of conformal radiotherapy in non-small-cell lung cancer.
OBJECTIVE
To report a retrospective study concerning the impact of fused 18F-fluoro-deoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and CT images on three-dimensional conformal radiotherapy planning for patients with non-small-cell lung cancer.


METHODS
A total of 101 patients consecutively treated for Stage I-III non-small-cell lung cancer were studied. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same treatment position. Images were coregistered using five fiducial markers. Target volume delineation was initially performed on the CT images, and the corresponding FDG-PET data were subsequently used as an overlay to the CT data to define the target volume.


RESULTS
18F-fluoro-deoxy-D-glucose-PET identified previously undetected distant metastatic disease in 8 patients, making them ineligible for curative conformal radiotherapy (1 patient presented with some positive uptake corresponding to concomitant pulmonary tuberculosis). Another patient was ineligible for curative treatment because the fused PET-CT images demonstrated excessively extensive intrathoracic disease. The gross tumor volume (GTV) was decreased by CT-PET image fusion in 21 patients (23%) and was increased in 24 patients (26%). The GTV reduction was > or = 25% in 7 patients because CT-PET image fusion reduced the pulmonary GTV in 6 patients (3 patients with atelectasis) and the mediastinal nodal GTV in 1 patient. The GTV increase was > or = 25% in 14 patients owing to an increase in the pulmonary GTV in 11 patients (4 patients with atelectasis) and detection of occult mediastinal lymph node involvement in 3 patients. Of 81 patients receiving a total dose of > or = 60 Gy at the International Commission on Radiation Units and Measurements point, after CT-PET image fusion, the percentage of total lung volume receiving >20 Gy increased in 15 cases and decreased in 22. The percentage of total heart volume receiving >36 Gy increased in 8 patients and decreased in 14. The spinal cord volume receiving at least 45 Gy (2 patients) decreased. Multivariate analysis showed that tumor with atelectasis was the single independent factor that resulted in a significant effect on the modification of the size of the GTV by FDG-PET: tumor with atelectasis (with vs. without atelectasis, p = 0.0001).


CONCLUSIONS
The results of our study have confirmed that integrated hybrid PET/CT in the treatment position and coregistered images have an impact on treatment planning and management of non-small-cell lung cancer. However, FDG images using dedicated PET scanners and respiration-gated acquisition protocols could improve the PET-CT image coregistration. Furthermore, the impact on treatment outcome remains to be demonstrated.
Deniaud-Alexandre
Elisabeth
E
Department of Radiation Oncology, Tenon Hospital A.P.-H.P., Paris, France.
Touboul
Emmanuel
E
Lerouge
Delphine
D
Grahek
Dany
D
Foulquier
Jean-Noël
JN
Petegnief
Yolande
Y
Grès
Benoît
B
El Balaa
Hanna
H
Keraudy
Katia
K
Kerrou
Kaldoun
K
Montravers
Françoise
F
Milleron
Bernard
B
Lebeau
Bernard
B
Talbot
Jean-Noël
JN
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000532:radiotherapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000379:methods*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18