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Title: Stereotactic, Single-Dose Irradiation of Lung Tumors: A Comparison of Absolute Dose and Dose Distribution Between Pencil Beam and Monte Carlo Algorithms Based on Actual Patient CT Scans

Abstract

Purpose: Dose calculation based on pencil beam (PB) algorithms has its shortcomings predicting dose in tissue heterogeneities. The aim of this study was to compare dose distributions of clinically applied non-intensity-modulated radiotherapy 15-MV plans for stereotactic body radiotherapy between voxel Monte Carlo (XVMC) calculation and PB calculation for lung lesions. Methods and Materials: To validate XVMC, one treatment plan was verified in an inhomogeneous thorax phantom with EDR2 film (Eastman Kodak, Rochester, NY). Both measured and calculated (PB and XVMC) dose distributions were compared regarding profiles and isodoses. Then, 35 lung plans originally created for clinical treatment by PB calculation with the Eclipse planning system (Varian Medical Systems, Palo Alto, CA) were recalculated by XVMC (investigational implementation in PrecisePLAN [Elekta AB, Stockholm, Sweden]). Clinically relevant dose-volume parameters for target and lung tissue were compared and analyzed statistically. Results: The XVMC calculation agreed well with film measurements (<1% difference in lateral profile), whereas the deviation between PB calculation and film measurements was up to +15%. On analysis of 35 clinical cases, the mean dose, minimal dose and coverage dose value for 95% volume of gross tumor volume were 1.14 {+-} 1.72 Gy, 1.68 {+-} 1.47 Gy, and 1.24 {+-} 1.04 Gymore » lower by XVMC compared with PB, respectively (prescription dose, 30 Gy). The volume covered by the 9 Gy isodose of lung was 2.73% {+-} 3.12% higher when calculated by XVMC compared with PB. The largest differences were observed for small lesions circumferentially encompassed by lung tissue. Conclusions: Pencil beam dose calculation overestimates dose to the tumor and underestimates lung volumes exposed to a given dose consistently for 15-MV photons. The degree of difference between XVMC and PB is tumor size and location dependent. Therefore XVMC calculation is helpful to further optimize treatment planning.« less

Authors:
 [1];  [2];  [3];  [2];  [2];  [4];  [2];  [3]
  1. Department of Radiation Oncology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou (China)
  2. Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim (Germany)
  3. Department of Radiotherapy, St. Mary's Hospital Siegen, Siegen (Germany)
  4. (Germany)
Publication Date:
OSTI Identifier:
21438028
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 78; Journal Issue: 3; Other Information: DOI: 10.1016/j.ijrobp.2009.08.012; PII: S0360-3016(09)02963-0; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ALGORITHMS; CAT SCANNING; LUNGS; MONTE CARLO METHOD; NEOPLASMS; PLANNING; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; RADIOTHERAPY; BODY; CALCULATION METHODS; COMPUTERIZED TOMOGRAPHY; DIAGNOSTIC TECHNIQUES; DISEASES; DOSES; MATHEMATICAL LOGIC; MEDICINE; NUCLEAR MEDICINE; ORGANS; RADIOLOGY; RESPIRATORY SYSTEM; THERAPY; TOMOGRAPHY

Citation Formats

Chen Huixiao, Lohr, Frank, Fritz, Peter, Wenz, Frederik, Dobler, Barbara, Department of Radiotherapy, Regensburg University Medical Center, Regensburg, Lorenz, Friedlieb, and Muehlnickel, Werner, E-mail: medizinphysik.mks@t-online.d. Stereotactic, Single-Dose Irradiation of Lung Tumors: A Comparison of Absolute Dose and Dose Distribution Between Pencil Beam and Monte Carlo Algorithms Based on Actual Patient CT Scans. United States: N. p., 2010. Web. doi:10.1016/j.ijrobp.2009.08.012.
Chen Huixiao, Lohr, Frank, Fritz, Peter, Wenz, Frederik, Dobler, Barbara, Department of Radiotherapy, Regensburg University Medical Center, Regensburg, Lorenz, Friedlieb, & Muehlnickel, Werner, E-mail: medizinphysik.mks@t-online.d. Stereotactic, Single-Dose Irradiation of Lung Tumors: A Comparison of Absolute Dose and Dose Distribution Between Pencil Beam and Monte Carlo Algorithms Based on Actual Patient CT Scans. United States. doi:10.1016/j.ijrobp.2009.08.012.
Chen Huixiao, Lohr, Frank, Fritz, Peter, Wenz, Frederik, Dobler, Barbara, Department of Radiotherapy, Regensburg University Medical Center, Regensburg, Lorenz, Friedlieb, and Muehlnickel, Werner, E-mail: medizinphysik.mks@t-online.d. Mon . "Stereotactic, Single-Dose Irradiation of Lung Tumors: A Comparison of Absolute Dose and Dose Distribution Between Pencil Beam and Monte Carlo Algorithms Based on Actual Patient CT Scans". United States. doi:10.1016/j.ijrobp.2009.08.012.
@article{osti_21438028,
title = {Stereotactic, Single-Dose Irradiation of Lung Tumors: A Comparison of Absolute Dose and Dose Distribution Between Pencil Beam and Monte Carlo Algorithms Based on Actual Patient CT Scans},
author = {Chen Huixiao and Lohr, Frank and Fritz, Peter and Wenz, Frederik and Dobler, Barbara and Department of Radiotherapy, Regensburg University Medical Center, Regensburg and Lorenz, Friedlieb and Muehlnickel, Werner, E-mail: medizinphysik.mks@t-online.d},
abstractNote = {Purpose: Dose calculation based on pencil beam (PB) algorithms has its shortcomings predicting dose in tissue heterogeneities. The aim of this study was to compare dose distributions of clinically applied non-intensity-modulated radiotherapy 15-MV plans for stereotactic body radiotherapy between voxel Monte Carlo (XVMC) calculation and PB calculation for lung lesions. Methods and Materials: To validate XVMC, one treatment plan was verified in an inhomogeneous thorax phantom with EDR2 film (Eastman Kodak, Rochester, NY). Both measured and calculated (PB and XVMC) dose distributions were compared regarding profiles and isodoses. Then, 35 lung plans originally created for clinical treatment by PB calculation with the Eclipse planning system (Varian Medical Systems, Palo Alto, CA) were recalculated by XVMC (investigational implementation in PrecisePLAN [Elekta AB, Stockholm, Sweden]). Clinically relevant dose-volume parameters for target and lung tissue were compared and analyzed statistically. Results: The XVMC calculation agreed well with film measurements (<1% difference in lateral profile), whereas the deviation between PB calculation and film measurements was up to +15%. On analysis of 35 clinical cases, the mean dose, minimal dose and coverage dose value for 95% volume of gross tumor volume were 1.14 {+-} 1.72 Gy, 1.68 {+-} 1.47 Gy, and 1.24 {+-} 1.04 Gy lower by XVMC compared with PB, respectively (prescription dose, 30 Gy). The volume covered by the 9 Gy isodose of lung was 2.73% {+-} 3.12% higher when calculated by XVMC compared with PB. The largest differences were observed for small lesions circumferentially encompassed by lung tissue. Conclusions: Pencil beam dose calculation overestimates dose to the tumor and underestimates lung volumes exposed to a given dose consistently for 15-MV photons. The degree of difference between XVMC and PB is tumor size and location dependent. Therefore XVMC calculation is helpful to further optimize treatment planning.},
doi = {10.1016/j.ijrobp.2009.08.012},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 3,
volume = 78,
place = {United States},
year = {Mon Nov 01 00:00:00 EDT 2010},
month = {Mon Nov 01 00:00:00 EDT 2010}
}