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Title: Portal imaging practice patterns of children's oncology group institutions: Dosimetric assessment and recommendations for minimizing unnecessary exposure

Abstract

Purpose: To determine and analyze the dosimetric consequences of current portal imaging practices for pediatric patients, and make specific recommendations for reducing exposure from portal imaging procedures. Methods and Materials: A survey was sent to approximately 250 Children's Oncology Group (COG) member institutions asking a series of questions about their portal imaging practices. Three case studies are presented with dosimetric analysis to illustrate the magnitude of unintended dose received by nontarget tissues using the most common techniques from the survey. Results: The vast majority of centers use double-exposure portal image techniques with a variety of open field margins. Only 17% of portal images were obtained during treatment, and for other imaging methods, few centers subtract monitor units from the treatment delivery. The number of monitor units used was nearly the same regardless of imager type, including electronic portal imaging devices. Eighty-six percent imaged all fields the first week and 17% imaged all fields every week. An additional 1,112 cm{sup 3} of nontarget tissue received 1 Gy in one of the example cases. Eight new recommendations are made, which will lower nontarget radiation doses with minimal impact on treatment verification accuracy. Conclusion: Based on the survey, changes can be made inmore » portal imaging practices that will lower nontarget doses. It is anticipated that treatment verification accuracy will be minimally affected. Specific recommendations made to decrease the imaging dose and help lower the rate of radiation-induced secondary cancers in children are proposed for inclusion in future COG protocols using radiation therapy.« less

Authors:
 [1];  [2];  [3];  [4];  [4]
  1. Department of Radiation Oncology, University of Southern California Keck School of Medicine and Childrens Hospital Los Angeles, Los Angeles, CA (United States). E-mail: aolch@chla.usc.edu
  2. Department of Medical Physics and Engineering Physics, University of Wisconsin, Madison, WI (United States)
  3. Department of Medical Physics and Human Oncology, University of Wisconsin, Madison, WI (United States)
  4. Division of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)
Publication Date:
OSTI Identifier:
20944707
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 67; Journal Issue: 2; Other Information: DOI: 10.1016/j.ijrobp.2006.10.004; PII: S0360-3016(06)03245-7; Copyright (c) 2007 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; ACCURACY; CHILDREN; IMAGES; NEOPLASMS; PATIENTS; PEDIATRICS; RADIATION DOSES; RADIOTHERAPY; RECOMMENDATIONS; VERIFICATION

Citation Formats

Olch, Arthur J., Geurts, Mark, Thomadsen, Bruce, Famiglietti, Robin, and Chang, Eric L. Portal imaging practice patterns of children's oncology group institutions: Dosimetric assessment and recommendations for minimizing unnecessary exposure. United States: N. p., 2007. Web. doi:10.1016/j.ijrobp.2006.10.004.
Olch, Arthur J., Geurts, Mark, Thomadsen, Bruce, Famiglietti, Robin, & Chang, Eric L. Portal imaging practice patterns of children's oncology group institutions: Dosimetric assessment and recommendations for minimizing unnecessary exposure. United States. doi:10.1016/j.ijrobp.2006.10.004.
Olch, Arthur J., Geurts, Mark, Thomadsen, Bruce, Famiglietti, Robin, and Chang, Eric L. Thu . "Portal imaging practice patterns of children's oncology group institutions: Dosimetric assessment and recommendations for minimizing unnecessary exposure". United States. doi:10.1016/j.ijrobp.2006.10.004.
@article{osti_20944707,
title = {Portal imaging practice patterns of children's oncology group institutions: Dosimetric assessment and recommendations for minimizing unnecessary exposure},
author = {Olch, Arthur J. and Geurts, Mark and Thomadsen, Bruce and Famiglietti, Robin and Chang, Eric L.},
abstractNote = {Purpose: To determine and analyze the dosimetric consequences of current portal imaging practices for pediatric patients, and make specific recommendations for reducing exposure from portal imaging procedures. Methods and Materials: A survey was sent to approximately 250 Children's Oncology Group (COG) member institutions asking a series of questions about their portal imaging practices. Three case studies are presented with dosimetric analysis to illustrate the magnitude of unintended dose received by nontarget tissues using the most common techniques from the survey. Results: The vast majority of centers use double-exposure portal image techniques with a variety of open field margins. Only 17% of portal images were obtained during treatment, and for other imaging methods, few centers subtract monitor units from the treatment delivery. The number of monitor units used was nearly the same regardless of imager type, including electronic portal imaging devices. Eighty-six percent imaged all fields the first week and 17% imaged all fields every week. An additional 1,112 cm{sup 3} of nontarget tissue received 1 Gy in one of the example cases. Eight new recommendations are made, which will lower nontarget radiation doses with minimal impact on treatment verification accuracy. Conclusion: Based on the survey, changes can be made in portal imaging practices that will lower nontarget doses. It is anticipated that treatment verification accuracy will be minimally affected. Specific recommendations made to decrease the imaging dose and help lower the rate of radiation-induced secondary cancers in children are proposed for inclusion in future COG protocols using radiation therapy.},
doi = {10.1016/j.ijrobp.2006.10.004},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 2,
volume = 67,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}