skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A note on modeling of tumor regression for estimation of radiobiological parameters

Abstract

Purpose: Accurate calculation of radiobiological parameters is crucial to predicting radiation treatment response. Modeling differences may have a significant impact on derived parameters. In this study, the authors have integrated two existing models with kinetic differential equations to formulate a new tumor regression model for estimation of radiobiological parameters for individual patients. Methods: A system of differential equations that characterizes the birth-and-death process of tumor cells in radiation treatment was analytically solved. The solution of this system was used to construct an iterative model (Z-model). The model consists of three parameters: tumor doubling time T{sub d}, half-life of dead cells T{sub r}, and cell survival fraction SF{sub D} under dose D. The Jacobian determinant of this model was proposed as a constraint to optimize the three parameters for six head and neck cancer patients. The derived parameters were compared with those generated from the two existing models: Chvetsov's model (C-model) and Lim's model (L-model). The C-model and L-model were optimized with the parameter T{sub d} fixed. Results: With the Jacobian-constrained Z-model, the mean of the optimized cell survival fractions is 0.43 ± 0.08, and the half-life of dead cells averaged over the six patients is 17.5 ± 3.2 days. Themore » parameters T{sub r} and SF{sub D} optimized with the Z-model differ by 1.2% and 20.3% from those optimized with the T{sub d}-fixed C-model, and by 32.1% and 112.3% from those optimized with the T{sub d}-fixed L-model, respectively. Conclusions: The Z-model was analytically constructed from the differential equations of cell populations that describe changes in the number of different tumor cells during the course of radiation treatment. The Jacobian constraints were proposed to optimize the three radiobiological parameters. The generated model and its optimization method may help develop high-quality treatment regimens for individual patients.« less

Authors:
;  [1]
  1. Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan 48202 (United States)
Publication Date:
OSTI Identifier:
22409919
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 41; Journal Issue: 8; 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; HEAD; ITERATIVE METHODS; NECK; NEOPLASMS; OPTIMIZATION; PATIENTS; TUMOR CELLS

Citation Formats

Zhong, Hualiang, and Chetty, Indrin. A note on modeling of tumor regression for estimation of radiobiological parameters. United States: N. p., 2014. Web. doi:10.1118/1.4884019.
Zhong, Hualiang, & Chetty, Indrin. A note on modeling of tumor regression for estimation of radiobiological parameters. United States. https://doi.org/10.1118/1.4884019
Zhong, Hualiang, and Chetty, Indrin. 2014. "A note on modeling of tumor regression for estimation of radiobiological parameters". United States. https://doi.org/10.1118/1.4884019.
@article{osti_22409919,
title = {A note on modeling of tumor regression for estimation of radiobiological parameters},
author = {Zhong, Hualiang and Chetty, Indrin},
abstractNote = {Purpose: Accurate calculation of radiobiological parameters is crucial to predicting radiation treatment response. Modeling differences may have a significant impact on derived parameters. In this study, the authors have integrated two existing models with kinetic differential equations to formulate a new tumor regression model for estimation of radiobiological parameters for individual patients. Methods: A system of differential equations that characterizes the birth-and-death process of tumor cells in radiation treatment was analytically solved. The solution of this system was used to construct an iterative model (Z-model). The model consists of three parameters: tumor doubling time T{sub d}, half-life of dead cells T{sub r}, and cell survival fraction SF{sub D} under dose D. The Jacobian determinant of this model was proposed as a constraint to optimize the three parameters for six head and neck cancer patients. The derived parameters were compared with those generated from the two existing models: Chvetsov's model (C-model) and Lim's model (L-model). The C-model and L-model were optimized with the parameter T{sub d} fixed. Results: With the Jacobian-constrained Z-model, the mean of the optimized cell survival fractions is 0.43 ± 0.08, and the half-life of dead cells averaged over the six patients is 17.5 ± 3.2 days. The parameters T{sub r} and SF{sub D} optimized with the Z-model differ by 1.2% and 20.3% from those optimized with the T{sub d}-fixed C-model, and by 32.1% and 112.3% from those optimized with the T{sub d}-fixed L-model, respectively. Conclusions: The Z-model was analytically constructed from the differential equations of cell populations that describe changes in the number of different tumor cells during the course of radiation treatment. The Jacobian constraints were proposed to optimize the three radiobiological parameters. The generated model and its optimization method may help develop high-quality treatment regimens for individual patients.},
doi = {10.1118/1.4884019},
url = {https://www.osti.gov/biblio/22409919}, journal = {Medical Physics},
issn = {0094-2405},
number = 8,
volume = 41,
place = {United States},
year = {Fri Aug 15 00:00:00 EDT 2014},
month = {Fri Aug 15 00:00:00 EDT 2014}
}