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Updated: Jul 8, 2026
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Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification (ADCI) and Dose Estimation
Published on: September 4, 2017
A new formula for normal tissue complication probability (NTCP) as a function of equivalent uniform dose (EUD)
Gary Luxton1, Paul J Keall, Christopher R King
1Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA. gluxton@stanford.edu
Physics in Medicine and Biology
|January 10, 2008
Summary
A new exponential function simplifies normal tissue complication probability (NTCP) calculations, closely matching the Lyman formula. This facilitates treatment planning by enabling easier conversion of organ-at-risk data for radiation therapy.
Area of Science:
- Radiation Oncology
- Medical Physics
- Biophysical Modeling
Background:
- Accurate normal tissue complication probability (NTCP) calculation is crucial for radiation treatment planning.
- The Lyman formula is a standard but complex method for NTCP estimation.
- Existing NTCP models require parameter conversion for different organs at risk (OARs).
Purpose of the Study:
- To introduce a simplified exponential function as an equivalent to the Lyman formula for NTCP calculations.
- To enable straightforward conversion of Lyman parameters for OARs into the new model.
- To represent NTCP as a function of Equivalent Uniform Dose (EUD) for non-homogeneously irradiated OARs.
Main Methods:
- Developed a single-parameter exponential function to approximate Lyman NTCP calculations (within 0.3%).
- Defined organ parameters for the new formula using Lyman model parameters (m, TD50).
- Utilized the Kutcher-Burman (LKB) model to relate dose, volume, and EUD for non-homogeneous irradiation.
Main Results:
- The exponential function closely reproduces Lyman NTCP values.
- Parameters for the new formula are readily derived from or converted to Lyman parameters.
- NTCP is effectively represented as a function of EUD, simplifying analysis for non-homogeneous dose distributions.
Conclusions:
- The proposed exponential function offers a simpler and accurate alternative to the Lyman formula for NTCP calculation.
- This simplification facilitates the integration of biological outcome modeling into clinical treatment planning.
- The model allows for the generation of EUD vs. NTCP tables for various OARs using established parameter sets.
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