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Title: Characterization and Management of Interfractional Anatomic Changes for Pancreatic Cancer Radiotherapy

Abstract

Purpose: To quantitatively characterize interfractional anatomic variations in pancreatic cancer radiotherapy (RT) and to study dosimetric advantages for using an online adaptive replanning scheme to account for these variations. Methods and Materials: Targets and organs at risk (OAR) were delineated by autosegmentation based on daily computed tomography (CT) images acquired using a respiration-gated in-room CT during daily image-guided RT (IGRT) for 10 pancreatic cancer patients. Various parameters, including the maximum overlap ratio (MOR) between the volumes based on planning and daily CTs for a structure, while the overlapping volumes were maximized, were used to quantify the interfractional organ deformation with the intrafractional variations largely excluded. An online adaptive RT (ART) was applied to these daily CTs. To evaluate the dosimetric benefits of ART, the dose distributions from the online ART were compared to those from the repositioning in the current standard IGRT practice. Results: The interfractional anatomic variations, particularly the organ deformation, are significant during pancreas irradiation. For the patients studied, the average MORs of all daily CTs were 80.2%, 61.7%, and 72.2% for pancreatic head, duodenum, and stomach, respectively. The online ART leads to improved dosimetric plan with better target coverage and/or OAR sparing than IGRT repositioning. For themore » patients studied, the mean V{sub 50.4Gy} (volume covered by 50.4 Gy) for the duodenum was reduced from 43.4% for IGRT to 15.6% for the online ART scheme. Conclusions: The online adaptive RT scheme can effectively account for the significant interfractional anatomic variations observed in pancreas irradiation. The dosimetric advantages with the online ART may enable safe dose escalation in radiation therapy for pancreatic cancer.« less

Authors:
; ;  [1]
  1. Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States)
Publication Date:
OSTI Identifier:
22058931
Resource Type:
Journal Article
Journal Name:
International Journal of Radiation Oncology, Biology and Physics
Additional Journal Information:
Journal Volume: 83; Journal Issue: 3; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0360-3016
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; CAT SCANNING; HAZARDS; HEAD; IMAGES; IRRADIATION; NEOPLASMS; PANCREAS; PATIENTS; PLANNING; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; RADIOTHERAPY; RESPIRATION; SMALL INTESTINE; STOMACH

Citation Formats

Feng, Liu, Erickson, Beth, Cheng, Peng, and Li, X. Allen, E-mail: ali@mcw.edu. Characterization and Management of Interfractional Anatomic Changes for Pancreatic Cancer Radiotherapy. United States: N. p., 2012. Web. doi:10.1016/J.IJROBP.2011.12.073.
Feng, Liu, Erickson, Beth, Cheng, Peng, & Li, X. Allen, E-mail: ali@mcw.edu. Characterization and Management of Interfractional Anatomic Changes for Pancreatic Cancer Radiotherapy. United States. https://doi.org/10.1016/J.IJROBP.2011.12.073
Feng, Liu, Erickson, Beth, Cheng, Peng, and Li, X. Allen, E-mail: ali@mcw.edu. 2012. "Characterization and Management of Interfractional Anatomic Changes for Pancreatic Cancer Radiotherapy". United States. https://doi.org/10.1016/J.IJROBP.2011.12.073.
@article{osti_22058931,
title = {Characterization and Management of Interfractional Anatomic Changes for Pancreatic Cancer Radiotherapy},
author = {Feng, Liu and Erickson, Beth and Cheng, Peng and Li, X. Allen, E-mail: ali@mcw.edu},
abstractNote = {Purpose: To quantitatively characterize interfractional anatomic variations in pancreatic cancer radiotherapy (RT) and to study dosimetric advantages for using an online adaptive replanning scheme to account for these variations. Methods and Materials: Targets and organs at risk (OAR) were delineated by autosegmentation based on daily computed tomography (CT) images acquired using a respiration-gated in-room CT during daily image-guided RT (IGRT) for 10 pancreatic cancer patients. Various parameters, including the maximum overlap ratio (MOR) between the volumes based on planning and daily CTs for a structure, while the overlapping volumes were maximized, were used to quantify the interfractional organ deformation with the intrafractional variations largely excluded. An online adaptive RT (ART) was applied to these daily CTs. To evaluate the dosimetric benefits of ART, the dose distributions from the online ART were compared to those from the repositioning in the current standard IGRT practice. Results: The interfractional anatomic variations, particularly the organ deformation, are significant during pancreas irradiation. For the patients studied, the average MORs of all daily CTs were 80.2%, 61.7%, and 72.2% for pancreatic head, duodenum, and stomach, respectively. The online ART leads to improved dosimetric plan with better target coverage and/or OAR sparing than IGRT repositioning. For the patients studied, the mean V{sub 50.4Gy} (volume covered by 50.4 Gy) for the duodenum was reduced from 43.4% for IGRT to 15.6% for the online ART scheme. Conclusions: The online adaptive RT scheme can effectively account for the significant interfractional anatomic variations observed in pancreas irradiation. The dosimetric advantages with the online ART may enable safe dose escalation in radiation therapy for pancreatic cancer.},
doi = {10.1016/J.IJROBP.2011.12.073},
url = {https://www.osti.gov/biblio/22058931}, journal = {International Journal of Radiation Oncology, Biology and Physics},
issn = {0360-3016},
number = 3,
volume = 83,
place = {United States},
year = {Sun Jul 01 00:00:00 EDT 2012},
month = {Sun Jul 01 00:00:00 EDT 2012}
}