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Title: SU-E-J-267: Weekly Volumetric and Dosimetric Changes in Adaptive Conformal Radiotherapy of Non-Small-Cell-Lung Cancer Using 4D CT and Gating

Abstract

Purpose: This study was to evaluate the significance of weekly imageguided patient setup and to assess the volumetric and dosimetric changes in no-small-cell-lung cancer (NSCLC) patients treated with adaptive conformal radiotherapy (CRT). Methods: 9 NSCLC patients treated with 3D CRT underwent 4D CT-on-rail every five fractions. ITV was generated from three phases of the 4DCT (the end of exhalation, 25% before and after the end of exhalation). The margin of ITV to PTV is 5mm. 6 weekly CTs were acquired for each patient. The weekly CTs were fused with the planning CT by vertebrae. The couch shift was recorded for each weekly CT to evaluate the setup error. The gross tumor volumes (GTVs) were contoured on weekly CT images by a physician. Beams from the original plans were applied to weekly CTs to calculate the delivered doses. All patients underwent replanning after 20 fractions. Results: Among the total 54 CTs, the average setup error was 2.0± 1.7, 2.6± 2.1, 2.7± 2.2 mm in X, Y, and Z direction, respectively. The average volume of the primary GTV was reduced from 42.45 cc to 22.78 cc (47.04%) after 6 weeks. The maximal volume regression occurred between 15 and 20 fractions. Adaptive radiationmore » therapy (ART) reduced the V20 and V5 of the lung by 33.5% and 16.89%, respectively. ART also reduced Dmean and D1/3 of the heart by 31.7% and 32.32%, respectively. Dmax of the spinal cord did not vary much during the treatment course. Conclusion: 5 mm margin is sufficient for 4D weekly CTguided radiotherapy in lung cancer. Tumor regression was observed in the majority of patients. ART significantly reduced the OARs dose. Our preliminary results indicated that an off-line ART approach is appropriate in clinical practice.« less

Authors:
 [1];  [2]; ; ; ;  [1]
  1. the 6th People's Hospital of Shanghai Jiaotong University, Shanghai, Shanghai (China)
  2. Cleveland Clinic, Cleveland, OH (United States)
Publication Date:
OSTI Identifier:
22339946
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 41; Journal Issue: 6; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; BEAMS; COMPUTERIZED TOMOGRAPHY; ERRORS; EXHALATION; HEART; LUNGS; NEOPLASMS; PATIENTS; PLANNING; PROFITS; RADIOTHERAPY; SPINAL CORD; VERTEBRAE

Citation Formats

Li, Z, Cleveland Clinic, Cleveland, OH, Shang, Q, Xiong, F, Zhang, X, Zhang, Q, and Fu, S. SU-E-J-267: Weekly Volumetric and Dosimetric Changes in Adaptive Conformal Radiotherapy of Non-Small-Cell-Lung Cancer Using 4D CT and Gating. United States: N. p., 2014. Web. doi:10.1118/1.4888321.
Li, Z, Cleveland Clinic, Cleveland, OH, Shang, Q, Xiong, F, Zhang, X, Zhang, Q, & Fu, S. SU-E-J-267: Weekly Volumetric and Dosimetric Changes in Adaptive Conformal Radiotherapy of Non-Small-Cell-Lung Cancer Using 4D CT and Gating. United States. https://doi.org/10.1118/1.4888321
Li, Z, Cleveland Clinic, Cleveland, OH, Shang, Q, Xiong, F, Zhang, X, Zhang, Q, and Fu, S. 2014. "SU-E-J-267: Weekly Volumetric and Dosimetric Changes in Adaptive Conformal Radiotherapy of Non-Small-Cell-Lung Cancer Using 4D CT and Gating". United States. https://doi.org/10.1118/1.4888321.
@article{osti_22339946,
title = {SU-E-J-267: Weekly Volumetric and Dosimetric Changes in Adaptive Conformal Radiotherapy of Non-Small-Cell-Lung Cancer Using 4D CT and Gating},
author = {Li, Z and Cleveland Clinic, Cleveland, OH and Shang, Q and Xiong, F and Zhang, X and Zhang, Q and Fu, S},
abstractNote = {Purpose: This study was to evaluate the significance of weekly imageguided patient setup and to assess the volumetric and dosimetric changes in no-small-cell-lung cancer (NSCLC) patients treated with adaptive conformal radiotherapy (CRT). Methods: 9 NSCLC patients treated with 3D CRT underwent 4D CT-on-rail every five fractions. ITV was generated from three phases of the 4DCT (the end of exhalation, 25% before and after the end of exhalation). The margin of ITV to PTV is 5mm. 6 weekly CTs were acquired for each patient. The weekly CTs were fused with the planning CT by vertebrae. The couch shift was recorded for each weekly CT to evaluate the setup error. The gross tumor volumes (GTVs) were contoured on weekly CT images by a physician. Beams from the original plans were applied to weekly CTs to calculate the delivered doses. All patients underwent replanning after 20 fractions. Results: Among the total 54 CTs, the average setup error was 2.0± 1.7, 2.6± 2.1, 2.7± 2.2 mm in X, Y, and Z direction, respectively. The average volume of the primary GTV was reduced from 42.45 cc to 22.78 cc (47.04%) after 6 weeks. The maximal volume regression occurred between 15 and 20 fractions. Adaptive radiation therapy (ART) reduced the V20 and V5 of the lung by 33.5% and 16.89%, respectively. ART also reduced Dmean and D1/3 of the heart by 31.7% and 32.32%, respectively. Dmax of the spinal cord did not vary much during the treatment course. Conclusion: 5 mm margin is sufficient for 4D weekly CTguided radiotherapy in lung cancer. Tumor regression was observed in the majority of patients. ART significantly reduced the OARs dose. Our preliminary results indicated that an off-line ART approach is appropriate in clinical practice.},
doi = {10.1118/1.4888321},
url = {https://www.osti.gov/biblio/22339946}, journal = {Medical Physics},
issn = {0094-2405},
number = 6,
volume = 41,
place = {United States},
year = {Sun Jun 01 00:00:00 EDT 2014},
month = {Sun Jun 01 00:00:00 EDT 2014}
}