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Title: A technique for adaptive image-guided helical tomotherapy for lung cancer

Abstract

Purpose: The gross tumor volume (GTV) for many lung cancer patients can decrease during the course of radiation therapy. As the tumor reduces in size during treatment, the margin added around the GTV effectively becomes larger, which can result in the excessive irradiation of normal lung tissue. The specific goal of this study is to evaluate the feasibility of using image-guided adaptive radiation therapy to adjust the planning target volume weekly based on the previous week's CT image sets that were used for image-guided patient setup. Methods and Materials: Megavoltage computed tomography (MVCT) images of the GTV were acquired daily on a helical tomotherapy system. These images were used to position the patient and to measure reduction in GTV volume. A planning study was conducted to determine the amount of lung-sparing that could have been achieved if adaptive therapy had been used. Treatment plans were created in which the target volumes were reduced after tumor reduction was measured. Results: A total of 158 MVCT imaging sessions were performed on 7 lung patients. The GTV was reduced by 60-80% during the course of treatment. The tumor reduction in the first 60 days of treatment can be modeled using the second-order polynomialmore » R 0.0002t {sup 2} - 0.0219t + 1.0, where R is the percent reduction in GTV, and t is the number of elapsed days. Based on these treatment planning studies, the absolute volume of ipsilateral lung receiving 20 Gy can be reduced between 17% and 23% (21% mean) by adapting the treatment delivery. The benefits of adaptive therapy are the greatest for tumor volumes {>=}25 cm{sup 3} and are directly dependent on GTV reduction during treatment. Conclusions: Megavoltage CT-based image guidance can be used to position lung cancer patients daily. This has the potential to decrease margins associated with daily setup error. Furthermore, the adaptive therapy technique described in this article can decrease the volume of healthy lung tissue receiving above 20 Gy. However, further study is needed to determine whether adaptive therapy could result in the underdosing of microscopic extension.« less

Authors:
 [1];  [2];  [2];  [3];  [2];  [3];  [3]
  1. Department of Radiation Oncology, Thompson Cancer Survival Center, Knoxville, TN (United States). E-mail: cramsey@utk.edu
  2. Department of Radiation Oncology, M.D. Anderson Cancer Center Orlando, Orlando, FL (United States)
  3. Department of Radiation Oncology, Thompson Cancer Survival Center, Knoxville, TN (United States)
Publication Date:
OSTI Identifier:
20793406
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 64; Journal Issue: 4; Other Information: DOI: 10.1016/j.ijrobp.2005.11.012; PII: S0360-3016(05)02947-0; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, 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; CARCINOMAS; COMPUTERIZED TOMOGRAPHY; ERRORS; IMAGES; IRRADIATION; LUNGS; PATIENTS; PLANNING; POLYNOMIALS; RADIOTHERAPY

Citation Formats

Ramsey, Chester R., Langen, Katja M., Kupelian, Patrick A., Scaperoth, Daniel D., Meeks, Sanford L., Mahan, Stephen L., and Seibert, Rebecca M. A technique for adaptive image-guided helical tomotherapy for lung cancer. United States: N. p., 2006. Web. doi:10.1016/J.IJROBP.2005.1.
Ramsey, Chester R., Langen, Katja M., Kupelian, Patrick A., Scaperoth, Daniel D., Meeks, Sanford L., Mahan, Stephen L., & Seibert, Rebecca M. A technique for adaptive image-guided helical tomotherapy for lung cancer. United States. doi:10.1016/J.IJROBP.2005.1.
Ramsey, Chester R., Langen, Katja M., Kupelian, Patrick A., Scaperoth, Daniel D., Meeks, Sanford L., Mahan, Stephen L., and Seibert, Rebecca M. Wed . "A technique for adaptive image-guided helical tomotherapy for lung cancer". United States. doi:10.1016/J.IJROBP.2005.1.
@article{osti_20793406,
title = {A technique for adaptive image-guided helical tomotherapy for lung cancer},
author = {Ramsey, Chester R. and Langen, Katja M. and Kupelian, Patrick A. and Scaperoth, Daniel D. and Meeks, Sanford L. and Mahan, Stephen L. and Seibert, Rebecca M.},
abstractNote = {Purpose: The gross tumor volume (GTV) for many lung cancer patients can decrease during the course of radiation therapy. As the tumor reduces in size during treatment, the margin added around the GTV effectively becomes larger, which can result in the excessive irradiation of normal lung tissue. The specific goal of this study is to evaluate the feasibility of using image-guided adaptive radiation therapy to adjust the planning target volume weekly based on the previous week's CT image sets that were used for image-guided patient setup. Methods and Materials: Megavoltage computed tomography (MVCT) images of the GTV were acquired daily on a helical tomotherapy system. These images were used to position the patient and to measure reduction in GTV volume. A planning study was conducted to determine the amount of lung-sparing that could have been achieved if adaptive therapy had been used. Treatment plans were created in which the target volumes were reduced after tumor reduction was measured. Results: A total of 158 MVCT imaging sessions were performed on 7 lung patients. The GTV was reduced by 60-80% during the course of treatment. The tumor reduction in the first 60 days of treatment can be modeled using the second-order polynomial R 0.0002t {sup 2} - 0.0219t + 1.0, where R is the percent reduction in GTV, and t is the number of elapsed days. Based on these treatment planning studies, the absolute volume of ipsilateral lung receiving 20 Gy can be reduced between 17% and 23% (21% mean) by adapting the treatment delivery. The benefits of adaptive therapy are the greatest for tumor volumes {>=}25 cm{sup 3} and are directly dependent on GTV reduction during treatment. Conclusions: Megavoltage CT-based image guidance can be used to position lung cancer patients daily. This has the potential to decrease margins associated with daily setup error. Furthermore, the adaptive therapy technique described in this article can decrease the volume of healthy lung tissue receiving above 20 Gy. However, further study is needed to determine whether adaptive therapy could result in the underdosing of microscopic extension.},
doi = {10.1016/J.IJROBP.2005.1},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 4,
volume = 64,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}