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Title: A method to evaluate dose errors introduced by dose mapping processes for mass conserving deformations

Abstract

Purpose: To present a method to evaluate the dose mapping error introduced by the dose mapping process. In addition, apply the method to evaluate the dose mapping error introduced by the 4D dose calculation process implemented in a research version of commercial treatment planning system for a patient case. Methods: The average dose accumulated in a finite volume should be unchanged when the dose delivered to one anatomic instance of that volume is mapped to a different anatomic instance--provided that the tissue deformation between the anatomic instances is mass conserving. The average dose to a finite volume on image S is defined as d{sub S}=e{sub s}/m{sub S}, where e{sub S} is the energy deposited in the mass m{sub S} contained in the volume. Since mass and energy should be conserved, when d{sub S} is mapped to an image R(d{sub S{yields}R}=d{sub R}), the mean dose mapping error is defined as {Delta}d{sub m}=|d{sub R}-d{sub S}|=|e{sub R}/m{sub R}-e{sub S}/m{sub S}|, where the e{sub R} and e{sub S} are integral doses (energy deposited), and m{sub R} and m{sub S} are the masses within the region of interest (ROI) on image R and the corresponding ROI on image S, where R and S are themore » two anatomic instances from the same patient. Alternatively, application of simple differential propagation yields the differential dose mapping error, {Delta}d{sub d}=|({partial_derivative}d/{partial_derivative}e)*{Delta}e+({partial_derivative}d/{partial_derivative}m)*{Delta}m|=|((e{sub S}-e{sub R})/m{sub R})-((m{sub S}-m{sub R})/m{sub R}{sup 2})*e{sub R}|={alpha}|d{sub R}-d{sub S}| with {alpha}=m{sub S}/m{sub R}. A 4D treatment plan on a ten-phase 4D-CT lung patient is used to demonstrate the dose mapping error evaluations for a patient case, in which the accumulated dose, D{sub R}={Sigma}{sub S=0}{sup 9}d{sub S{yields}R}, and associated error values ({Delta}D{sub m} and {Delta}D{sub d}) are calculated for a uniformly spaced set of ROIs. Results: For the single sample patient dose distribution, the average accumulated differential dose mapping error is 4.3%, the average absolute differential dose mapping error is 10.8%, and the average accumulated mean dose mapping error is 5.0%. Accumulated differential dose mapping errors within the gross tumor volume (GTV) and planning target volume (PTV) are lower, 0.73% and 2.33%, respectively. Conclusions: A method has been presented to evaluate the dose mapping error introduced by the dose mapping process. This method has been applied to evaluate the 4D dose calculation process implemented in a commercial treatment planning system. The method could potentially be developed as a fully-automatic QA method in image guided adaptive radiation therapy (IGART).« less

Authors:
; ; ; ; ; ;  [1]
  1. Department of Radiation Oncology, Virginia Commonwealth University, P.O. Box 980058, Richmond, Virginia 23298 (United States)
Publication Date:
OSTI Identifier:
22098821
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 39; Journal Issue: 4; Other Information: (c) 2012 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:
62 RADIOLOGY AND NUCLEAR MEDICINE; 61 RADIATION PROTECTION AND DOSIMETRY; CASE METHOD; COMPUTERIZED TOMOGRAPHY; D S MESONS; DOSIMETRY; ERRORS; EVALUATION; IMAGE PROCESSING; INTEGRAL DOSES; LUNGS; MASS; NEOPLASMS; PATIENTS; PLANNING; QUALITY ASSURANCE; RADIATION DOSE DISTRIBUTIONS; RADIOTHERAPY

Citation Formats

Yan, C., Hugo, G., Salguero, F. J., Saleh-Sayah, N., Weiss, E., Sleeman, W. C., and Siebers, J. V. A method to evaluate dose errors introduced by dose mapping processes for mass conserving deformations. United States: N. p., 2012. Web. doi:10.1118/1.3684951.
Yan, C., Hugo, G., Salguero, F. J., Saleh-Sayah, N., Weiss, E., Sleeman, W. C., & Siebers, J. V. A method to evaluate dose errors introduced by dose mapping processes for mass conserving deformations. United States. https://doi.org/10.1118/1.3684951
Yan, C., Hugo, G., Salguero, F. J., Saleh-Sayah, N., Weiss, E., Sleeman, W. C., and Siebers, J. V. 2012. "A method to evaluate dose errors introduced by dose mapping processes for mass conserving deformations". United States. https://doi.org/10.1118/1.3684951.
@article{osti_22098821,
title = {A method to evaluate dose errors introduced by dose mapping processes for mass conserving deformations},
author = {Yan, C. and Hugo, G. and Salguero, F. J. and Saleh-Sayah, N. and Weiss, E. and Sleeman, W. C. and Siebers, J. V.},
abstractNote = {Purpose: To present a method to evaluate the dose mapping error introduced by the dose mapping process. In addition, apply the method to evaluate the dose mapping error introduced by the 4D dose calculation process implemented in a research version of commercial treatment planning system for a patient case. Methods: The average dose accumulated in a finite volume should be unchanged when the dose delivered to one anatomic instance of that volume is mapped to a different anatomic instance--provided that the tissue deformation between the anatomic instances is mass conserving. The average dose to a finite volume on image S is defined as d{sub S}=e{sub s}/m{sub S}, where e{sub S} is the energy deposited in the mass m{sub S} contained in the volume. Since mass and energy should be conserved, when d{sub S} is mapped to an image R(d{sub S{yields}R}=d{sub R}), the mean dose mapping error is defined as {Delta}d{sub m}=|d{sub R}-d{sub S}|=|e{sub R}/m{sub R}-e{sub S}/m{sub S}|, where the e{sub R} and e{sub S} are integral doses (energy deposited), and m{sub R} and m{sub S} are the masses within the region of interest (ROI) on image R and the corresponding ROI on image S, where R and S are the two anatomic instances from the same patient. Alternatively, application of simple differential propagation yields the differential dose mapping error, {Delta}d{sub d}=|({partial_derivative}d/{partial_derivative}e)*{Delta}e+({partial_derivative}d/{partial_derivative}m)*{Delta}m|=|((e{sub S}-e{sub R})/m{sub R})-((m{sub S}-m{sub R})/m{sub R}{sup 2})*e{sub R}|={alpha}|d{sub R}-d{sub S}| with {alpha}=m{sub S}/m{sub R}. A 4D treatment plan on a ten-phase 4D-CT lung patient is used to demonstrate the dose mapping error evaluations for a patient case, in which the accumulated dose, D{sub R}={Sigma}{sub S=0}{sup 9}d{sub S{yields}R}, and associated error values ({Delta}D{sub m} and {Delta}D{sub d}) are calculated for a uniformly spaced set of ROIs. Results: For the single sample patient dose distribution, the average accumulated differential dose mapping error is 4.3%, the average absolute differential dose mapping error is 10.8%, and the average accumulated mean dose mapping error is 5.0%. Accumulated differential dose mapping errors within the gross tumor volume (GTV) and planning target volume (PTV) are lower, 0.73% and 2.33%, respectively. Conclusions: A method has been presented to evaluate the dose mapping error introduced by the dose mapping process. This method has been applied to evaluate the 4D dose calculation process implemented in a commercial treatment planning system. The method could potentially be developed as a fully-automatic QA method in image guided adaptive radiation therapy (IGART).},
doi = {10.1118/1.3684951},
url = {https://www.osti.gov/biblio/22098821}, journal = {Medical Physics},
issn = {0094-2405},
number = 4,
volume = 39,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2012},
month = {Sun Apr 15 00:00:00 EDT 2012}
}