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Title: Validation of a 4D-PET Maximum Intensity Projection for Delineation of an Internal Target Volume

Purpose: The delineation of internal target volumes (ITVs) in radiation therapy of lung tumors is currently performed by use of either free-breathing (FB) {sup 18}F-fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET/CT) or 4-dimensional (4D)-CT maximum intensity projection (MIP). In this report we validate the use of 4D-PET-MIP for the delineation of target volumes in both a phantom and in patients. Methods and Materials: A phantom with 3 hollow spheres was prepared surrounded by air then water. The spheres and water background were filled with a mixture of {sup 18}F and radiographic contrast medium. A 4D-PET/CT scan was performed of the phantom while moving in 4 different breathing patterns using a programmable motion device. Nine patients with an FDG-avid lung tumor who underwent FB and 4D-PET/CT and >5 mm of tumor motion were included for analysis. The 3 spheres and patient lesions were contoured by 2 contouring methods (40% of maximum and PET edge) on the FB-PET, FB-CT, 4D-PET, 4D-PET-MIP, and 4D-CT-MIP. The concordance between the different contoured volumes was calculated using a Dice coefficient (DC). The difference in lung tumor volumes between FB-PET and 4D-PET volumes was also measured. Results: The average DC in the phantom using 40% and PET edge, respectively,more » was lowest for FB-PET/CT (DCAir = 0.72/0.67, DCBackground 0.63/0.62) and highest for 4D-PET/CT-MIP (DCAir = 0.84/0.83, DCBackground = 0.78/0.73). The average DC in the 9 patients using 40% and PET edge, respectively, was also lowest for FB-PET/CT (DC = 0.45/0.44) and highest for 4D-PET/CT-MIP (DC = 0.72/0.73). In the 9 lesions, the target volumes of the FB-PET using 40% and PET edge, respectively, were on average 40% and 45% smaller than the 4D-PET-MIP. Conclusion: A 4D-PET-MIP produces volumes with the highest concordance with 4D-CT-MIP across multiple breathing patterns and lesion sizes in both a phantom and among patients. Freebreathing PET/CT consistently underestimates ITV when compared with 4D PET/CT for a lesion affected by respiration.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1] ;  [6] ;  [6] ;  [3] ;  [1] ;  [1] ;  [3]
  1. Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia)
  2. Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia)
  3. (Australia)
  4. Department of Medical Imaging and Radiation Science, Monash University, Clayton, Victoria (Australia)
  5. Department of Applied Physics, RMIT University, Melbourne (Australia)
  6. Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia)
Publication Date:
OSTI Identifier:
22224537
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 86; Journal Issue: 4; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; COMPUTERIZED TOMOGRAPHY; CONTRAST MEDIA; FLUORINE 18; FLUORODEOXYGLUCOSE; IMAGE PROCESSING; LUNGS; NEOPLASMS; PATIENTS; PHANTOMS; POSITRON COMPUTED TOMOGRAPHY; RADIOTHERAPY; RESPIRATION