Observation of interfractional variations in lung tumor position using respiratory gated and ungated megavoltage cone-beam computed tomography Journal Article


Authors: Chang, J.; Mageras, G. S.; Yorke, E.; De Arruda, F.; Sillanpaa, J.; Rosenzweig, K. E.; Hertanto, A.; Pham, H.; Seppi, E.; Pevsner, A.; Ling, C. C.; Amols, H.
Article Title: Observation of interfractional variations in lung tumor position using respiratory gated and ungated megavoltage cone-beam computed tomography
Abstract: Purpose: To evaluate the use of megavoltage cone-beam computed tomography (MV CBCT) to measure interfractional variation in lung tumor position. Methods and Materials: Eight non-small-cell lung cancer patients participated in the study, 4 with respiratory gating and 4 without. All patients underwent MV CBCT scanning at weekly intervals. Contoured planning CT and MV CBCT images were spatially registered based on vertebral anatomy, and displacements of the tumor centroid determined. Setup error was assessed by comparing weekly portal orthogonal radiographs with digitally reconstructed radiographs generated from planning CT images. Hypothesis testing was performed to test the statistical significance of the volume difference, centroid displacement, and setup uncertainty. Results: The vertebral bodies and soft tissue portions of tumor within lung were visible on the MV CBCT scans. Statistically significant systematic volume decrease over the course of treatment was observed for 1 patient. The average centroid displacement between simulation CT and MV CBCT scans were 2.5 mm, -2.0 mm, and -1.5 mm with standard deviations of 2.7 mm, 2.7 mm, and 2.6 mm in the right-left, anterior-posterior and superior-inferior directions. The mean setup errors were smaller than the centroid shifts, while the standard deviations were comparable. In most cases, the gross tumor volume (GTV) defined on the MV CBCT was located on average at least 5 mm inside a 10 mm expansion of the GTV defined on the planning CT scan. Conclusions: The MV CBCT technique can be used to image lung tumors and may prove valuable for image-guided radiotherapy. Our conclusions must be verified in view of the small patient number. © 2007 Elsevier Inc. All rights reserved.
Keywords: clinical article; cancer radiotherapy; cancer diagnosis; tumor localization; computer assisted tomography; observer variation; lung non small cell cancer; carcinoma, non-small-cell lung; lung neoplasms; radiotherapy; tomography, x-ray computed; patient monitoring; algorithms; simulation; computerized tomography; tumors; feasibility studies; radiation dose fractionation; radiotherapy planning, computer-assisted; particle accelerators; image reconstruction; cells; image-guided radiotherapy; movement; respiratory gating; megavoltage radiation; setup verification; interfractional variation; mega-voltage cbct; pulmonary diseases
Journal Title: International Journal of Radiation Oncology, Biology, Physics
Volume: 67
Issue: 5
ISSN: 0360-3016
Publisher: Elsevier Inc.  
Date Published: 2007-04-01
Start Page: 1548
End Page: 1558
Language: English
DOI: 10.1016/j.ijrobp.2006.11.055
PUBMED: 17394950
PROVIDER: scopus
PMCID: PMC2278042
DOI/URL:
Notes: --- - "Cited By (since 1996): 24" - "Export Date: 17 November 2011" - "CODEN: IOBPD" - "Source: Scopus"
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MSK Authors
  1. Alexander Pevsner
    12 Pevsner
  2. Jenghwa Chang
    63 Chang
  3. Gikas S Mageras
    273 Mageras
  4. Ellen D Yorke
    384 Yorke
  5. Howard I Amols
    157 Amols
  6. C Clifton Ling
    331 Ling
  7. Hai Pham
    37 Pham