SU‐EE‐A1‐01: Comparison of Monte Carlo and Convolution/Superposition Calculation Methods: Quantification of the Dose Prediction Errors Arising From Tissue Heterogeneities

Ivaylo B Mihaylov, F. Lerma, J. Siebers

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Purpose: To investigate the extent of the dose prediction error (DPE) due to tissue heterogeneities in superposition/convolution (SC) based dose calculations by comparisons with Monte Carlo (MC) calculations for head‐and‐neck IMRT treatment plans. Method and Materials: A retrospective investigation is performed for ten Head‐and‐Neck IMRT patients. Dose calculations are performed with SC and MC algorithms. For both algorithms, the intensity modulation generated by the dynamic multi‐leaf collimator (DMLC) is incorporated into the dose calculation via a transmission matrix generated by determining the ratio of incident and transmitted energy fluence through the DMLC using a MC algorithm. Plans were compared based upon the criteria used during the IMRT optimization: GTV D98, CTV D95, Nodal volume D90, Cord D02, and Parotid D50. As the same transmission matrix is used for both methods and the SC and MC algorithms subsequent dose differences are attributed to handling of the tissue heterogeneities by the SC algorithm. Results: The GTV D98 and CTV D95 local doses agree within ±3.2% for the SC and MC calculations. Differences are within ±1.8% for the D90 of the nodal target volume. The cord and the brainstem D02 doses differ by <±3.5% and <±2.5% of the local dose respectively. The Parotid D50 shows the greatest variations, with local differences up to 5.8%. The observed deviations do not show systematic under‐ or over‐estimate of the dose by SC. Conclusion: When identical transmission matrices are used, the DPE of the SC method, using the MC method as a references, is <±3.2% for the target structures. For the critical structures, DPEs as high as 6% of the local dose were observed, which corresponds to <3% if normalized to the prescription dose. (Supported by NIH‐1R01CA98524).

Original languageEnglish (US)
Pages (from-to)1901-1902
Number of pages2
JournalMedical Physics
Volume32
Issue number6
DOIs
StatePublished - 2005
Externally publishedYes

Fingerprint

Monte Carlo Method
Brain Stem
Prescriptions
Therapeutics

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

Cite this

@article{8fbb7f5fad6e4ef994b0b868c51b03d5,
title = "SU‐EE‐A1‐01: Comparison of Monte Carlo and Convolution/Superposition Calculation Methods: Quantification of the Dose Prediction Errors Arising From Tissue Heterogeneities",
abstract = "Purpose: To investigate the extent of the dose prediction error (DPE) due to tissue heterogeneities in superposition/convolution (SC) based dose calculations by comparisons with Monte Carlo (MC) calculations for head‐and‐neck IMRT treatment plans. Method and Materials: A retrospective investigation is performed for ten Head‐and‐Neck IMRT patients. Dose calculations are performed with SC and MC algorithms. For both algorithms, the intensity modulation generated by the dynamic multi‐leaf collimator (DMLC) is incorporated into the dose calculation via a transmission matrix generated by determining the ratio of incident and transmitted energy fluence through the DMLC using a MC algorithm. Plans were compared based upon the criteria used during the IMRT optimization: GTV D98, CTV D95, Nodal volume D90, Cord D02, and Parotid D50. As the same transmission matrix is used for both methods and the SC and MC algorithms subsequent dose differences are attributed to handling of the tissue heterogeneities by the SC algorithm. Results: The GTV D98 and CTV D95 local doses agree within ±3.2{\%} for the SC and MC calculations. Differences are within ±1.8{\%} for the D90 of the nodal target volume. The cord and the brainstem D02 doses differ by <±3.5{\%} and <±2.5{\%} of the local dose respectively. The Parotid D50 shows the greatest variations, with local differences up to 5.8{\%}. The observed deviations do not show systematic under‐ or over‐estimate of the dose by SC. Conclusion: When identical transmission matrices are used, the DPE of the SC method, using the MC method as a references, is <±3.2{\%} for the target structures. For the critical structures, DPEs as high as 6{\%} of the local dose were observed, which corresponds to <3{\%} if normalized to the prescription dose. (Supported by NIH‐1R01CA98524).",
author = "Mihaylov, {Ivaylo B} and F. Lerma and J. Siebers",
year = "2005",
doi = "10.1118/1.1997471",
language = "English (US)",
volume = "32",
pages = "1901--1902",
journal = "Medical Physics",
issn = "0094-2405",
publisher = "AAPM - American Association of Physicists in Medicine",
number = "6",

}

TY - JOUR

T1 - SU‐EE‐A1‐01

T2 - Comparison of Monte Carlo and Convolution/Superposition Calculation Methods: Quantification of the Dose Prediction Errors Arising From Tissue Heterogeneities

AU - Mihaylov, Ivaylo B

AU - Lerma, F.

AU - Siebers, J.

PY - 2005

Y1 - 2005

N2 - Purpose: To investigate the extent of the dose prediction error (DPE) due to tissue heterogeneities in superposition/convolution (SC) based dose calculations by comparisons with Monte Carlo (MC) calculations for head‐and‐neck IMRT treatment plans. Method and Materials: A retrospective investigation is performed for ten Head‐and‐Neck IMRT patients. Dose calculations are performed with SC and MC algorithms. For both algorithms, the intensity modulation generated by the dynamic multi‐leaf collimator (DMLC) is incorporated into the dose calculation via a transmission matrix generated by determining the ratio of incident and transmitted energy fluence through the DMLC using a MC algorithm. Plans were compared based upon the criteria used during the IMRT optimization: GTV D98, CTV D95, Nodal volume D90, Cord D02, and Parotid D50. As the same transmission matrix is used for both methods and the SC and MC algorithms subsequent dose differences are attributed to handling of the tissue heterogeneities by the SC algorithm. Results: The GTV D98 and CTV D95 local doses agree within ±3.2% for the SC and MC calculations. Differences are within ±1.8% for the D90 of the nodal target volume. The cord and the brainstem D02 doses differ by <±3.5% and <±2.5% of the local dose respectively. The Parotid D50 shows the greatest variations, with local differences up to 5.8%. The observed deviations do not show systematic under‐ or over‐estimate of the dose by SC. Conclusion: When identical transmission matrices are used, the DPE of the SC method, using the MC method as a references, is <±3.2% for the target structures. For the critical structures, DPEs as high as 6% of the local dose were observed, which corresponds to <3% if normalized to the prescription dose. (Supported by NIH‐1R01CA98524).

AB - Purpose: To investigate the extent of the dose prediction error (DPE) due to tissue heterogeneities in superposition/convolution (SC) based dose calculations by comparisons with Monte Carlo (MC) calculations for head‐and‐neck IMRT treatment plans. Method and Materials: A retrospective investigation is performed for ten Head‐and‐Neck IMRT patients. Dose calculations are performed with SC and MC algorithms. For both algorithms, the intensity modulation generated by the dynamic multi‐leaf collimator (DMLC) is incorporated into the dose calculation via a transmission matrix generated by determining the ratio of incident and transmitted energy fluence through the DMLC using a MC algorithm. Plans were compared based upon the criteria used during the IMRT optimization: GTV D98, CTV D95, Nodal volume D90, Cord D02, and Parotid D50. As the same transmission matrix is used for both methods and the SC and MC algorithms subsequent dose differences are attributed to handling of the tissue heterogeneities by the SC algorithm. Results: The GTV D98 and CTV D95 local doses agree within ±3.2% for the SC and MC calculations. Differences are within ±1.8% for the D90 of the nodal target volume. The cord and the brainstem D02 doses differ by <±3.5% and <±2.5% of the local dose respectively. The Parotid D50 shows the greatest variations, with local differences up to 5.8%. The observed deviations do not show systematic under‐ or over‐estimate of the dose by SC. Conclusion: When identical transmission matrices are used, the DPE of the SC method, using the MC method as a references, is <±3.2% for the target structures. For the critical structures, DPEs as high as 6% of the local dose were observed, which corresponds to <3% if normalized to the prescription dose. (Supported by NIH‐1R01CA98524).

UR - http://www.scopus.com/inward/record.url?scp=39149104695&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=39149104695&partnerID=8YFLogxK

U2 - 10.1118/1.1997471

DO - 10.1118/1.1997471

M3 - Article

AN - SCOPUS:39149104695

VL - 32

SP - 1901

EP - 1902

JO - Medical Physics

JF - Medical Physics

SN - 0094-2405

IS - 6

ER -