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Title: SU-E-T-32: A Feasibility Study of Independent Dose Verification for IMAT

Abstract

Purpose: To assess the feasibility of the independent dose verification (Indp) for intensity modulated arc therapy (IMAT). Methods: An independent dose calculation software program (Simple MU Analysis, Triangle Products, JP) was used in this study, which can compute the radiological path length from the surface to the reference point for each control point using patient’s CT image dataset and the MLC aperture shape was simultaneously modeled in reference to the information of MLC from DICOM-RT plan. Dose calculation was performed using a modified Clarkson method considering MLC transmission and dosimetric leaf gap. In this study, a retrospective analysis was conducted in which IMAT plans from 120 patients of the two sites (prostate / head and neck) from four institutes were retrospectively analyzed to compare the Indp to the TPS using patient CT images. In addition, an ion-chamber measurement was performed to verify the accuracy of the TPS and the Indp in water-equivalent phantom. Results: The agreements between the Indp and the TPS (mean±1SD) were −0.8±2.4% and −1.3±3.8% for the regions of prostate and head and neck, respectively. The measurement comparison showed similar results (−0.8±1.6% and 0.1±4.6% for prostate and head and neck). The variation was larger in the head andmore » neck because the number of the segments was increased that the reference point was under the MLC and the modified Clarkson method cannot consider the smooth falloff of the leaf penumbra. Conclusion: The independent verification program would be practical and effective for secondary check for IMAT with the sufficient accuracy in the measurement and CT-based calculation. The accuracy would be improved if considering the falloff of the leaf penumbra.« less

Authors:
; ;  [1]; ;  [2];  [3];  [4]
  1. The Cancer Institute Hospital of JFCR, Koutou-ku, Tokyo (Japan)
  2. The National Cancer Center Hospital East, Kashiwa-city, Chiba prefecture (Japan)
  3. Kobe City Medical Center General Hospital, Kobe, Hyogo (Japan)
  4. The National Center for Global Health and Medicine, Shinjuku-ku, Tokyo (Japan)
Publication Date:
OSTI Identifier:
22545166
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 42; Journal Issue: 6; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; ACCURACY; COMPUTER CODES; COMPUTERIZED TOMOGRAPHY; DATASETS; FEASIBILITY STUDIES; HEAD; IMAGE PROCESSING; IONIZATION CHAMBERS; NECK; PATIENTS; PHANTOMS; PROSTATE; RADIATION DOSES; RADIOTHERAPY; VERIFICATION

Citation Formats

Kamima, T, Takahashi, R, Sato, Y, Baba, H, Tachibana, H, Yamashita, M, and Sugawara, Y. SU-E-T-32: A Feasibility Study of Independent Dose Verification for IMAT. United States: N. p., 2015. Web. doi:10.1118/1.4924393.
Kamima, T, Takahashi, R, Sato, Y, Baba, H, Tachibana, H, Yamashita, M, & Sugawara, Y. SU-E-T-32: A Feasibility Study of Independent Dose Verification for IMAT. United States. doi:10.1118/1.4924393.
Kamima, T, Takahashi, R, Sato, Y, Baba, H, Tachibana, H, Yamashita, M, and Sugawara, Y. Mon . "SU-E-T-32: A Feasibility Study of Independent Dose Verification for IMAT". United States. doi:10.1118/1.4924393.
@article{osti_22545166,
title = {SU-E-T-32: A Feasibility Study of Independent Dose Verification for IMAT},
author = {Kamima, T and Takahashi, R and Sato, Y and Baba, H and Tachibana, H and Yamashita, M and Sugawara, Y},
abstractNote = {Purpose: To assess the feasibility of the independent dose verification (Indp) for intensity modulated arc therapy (IMAT). Methods: An independent dose calculation software program (Simple MU Analysis, Triangle Products, JP) was used in this study, which can compute the radiological path length from the surface to the reference point for each control point using patient’s CT image dataset and the MLC aperture shape was simultaneously modeled in reference to the information of MLC from DICOM-RT plan. Dose calculation was performed using a modified Clarkson method considering MLC transmission and dosimetric leaf gap. In this study, a retrospective analysis was conducted in which IMAT plans from 120 patients of the two sites (prostate / head and neck) from four institutes were retrospectively analyzed to compare the Indp to the TPS using patient CT images. In addition, an ion-chamber measurement was performed to verify the accuracy of the TPS and the Indp in water-equivalent phantom. Results: The agreements between the Indp and the TPS (mean±1SD) were −0.8±2.4% and −1.3±3.8% for the regions of prostate and head and neck, respectively. The measurement comparison showed similar results (−0.8±1.6% and 0.1±4.6% for prostate and head and neck). The variation was larger in the head and neck because the number of the segments was increased that the reference point was under the MLC and the modified Clarkson method cannot consider the smooth falloff of the leaf penumbra. Conclusion: The independent verification program would be practical and effective for secondary check for IMAT with the sufficient accuracy in the measurement and CT-based calculation. The accuracy would be improved if considering the falloff of the leaf penumbra.},
doi = {10.1118/1.4924393},
journal = {Medical Physics},
number = 6,
volume = 42,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}