Impact of manual and automated interpretation of fused PET/CT data on esophageal target definitions in radiation planning.
OBJECTIVE
We compare CT-only based esophageal tumor definition with two PET/CT based methods: (1) manual contouring and (2) a semiautomated method based on specific thresholds.


METHODS
Patients with esophageal cancer treated at Brigham and Women's Hospital from 2003 to 2006 were identified. CT-based tumor volumes were compared with manual PET/CT-based volumes and semiautomated PET-based tumor volumes. Differences were scored as (1) minor if the superior or inferior extent of the primary tumor (or both) differed by 1-2 cm and (2) major if the difference was > 2 cm or if different noncontiguous nodal regions were identified as being grossly involved.


RESULTS
Comparing CT-based gross tumor volumes (GTVs) to manually defined PET/CT-based GTVs, use of PET changed volumes for 21 of 25 (84%) patients: 12 patients (48%) exhibited minor differences, whereas for 9 patients (36%), the differences were major. For 4 (16%) patients, the major difference was due to discrepancy in celiac or distant mediastinal lymph node involvement. Use of automated PET volumes changed the manual PET length in 14 patients (56%): 8 minor and 6 major.


CONCLUSIONS
The use of PET/CT in treatment planning for esophageal cancer can affect target definition. Two PET-based techniques can also produce significantly different tumor volumes in a large percentage of patients. Further investigations to clarify the optimal use of PET/CT data in treatment planning are warranted.
Hong
Theodore S
TS
Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA.
Killoran
Joseph H
JH
Mamede
Marcelo
M
Mamon
Harvey J
HJ
D001331:Automation; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000379:methods; D012189:Retrospective Studies; D013899:Thoracic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D014057:Tomography, X-Ray Computed / Q000379:methods; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18