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Title: SU-G-BRB-09: Kompeito-Shot: Development of a Novel Verification System for 3D Beam Alignment Including the Sag of Gantry Head

Abstract

Purpose: High accuracy of beam axis is required for high-precision radiation therapy. It is impossible to quantitatively and directly evaluate the sagging effect of the gantry head using current methods (star-shot and Winston-Lutz tests) when the gantry head sags under the weight of MLC and X-Y jaws. We introduce a novel method “Kompeito-shot (3D star-shot)” for the verification of 3D beam alignment (3D isocentricity). This method enables direct measurement of the sagging effect. We developed the system and examined the concept of this system. Methods: The system composed of a plastic scintillator (PS), a truncated cone-shaped mirror, a plane mirror and a CCD camera. Two types of PS were compared. One consisted of a column PS (Co system), the other consisted of a column PS inserted into a barrel PS with shading film in between (Co-Ba system). The system was irradiated with a 6-MV photon beam and the scintillation light was measured using the CCD camera through the mirror system. The gantry angle was set from 270 to 300 degrees to mimic the sagging of the gantry head for evaluating the accuracy of the system. The distance between a center of PS and entrance / exit points were calculated tomore » analyze the gantry angle. And, the calculated gantry angle and the irradiated gantry angle were compared. Results: We compared the measured image of Co system and that of Co-Ba system. Entrance and exit areas were visualized clearly. The histogram showing the difference between the calculated gantry angle and the irradiated gantry angle was fitted with a Gaussian function. Mean and standard deviation of Co-Ba system were smaller than that of Co system by one order of magnitude. Conclusion: We developed the Kompeito-shot system and evaluated the accuracy of the system. The basic concept works for the verification of 3D isocentricity.« less

Authors:
;  [1]; ; ;  [1];  [2];  [3];  [4];  [5];  [1];  [2];  [1];  [2];  [2]
  1. Hiroshima University, Hiroshima (Japan)
  2. (Japan)
  3. Hiroshima University Hospital, Hiroshima (Japan)
  4. Rikkyo University, Tokyo (Japan)
  5. The University of Tokyo, Tokyo (Japan)
Publication Date:
OSTI Identifier:
22649281
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 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; A CENTERS; ACCURACY; ALIGNMENT; CHARGE-COUPLED DEVICES; COBALT; HEAD; IRRADIATION; PHOTON BEAMS; VERIFICATION; VISIBLE RADIATION

Citation Formats

Tsuneda, M, Nishio, T, Saito, A, Kawahara, D, Ochi, Y, Hiroshima University Hospital, Hiroshima, Hioki, K, Matsushita, K, Tanaka, S, Ozawa, S, Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Nagata, Y, Hiroshima University Hospital, Hiroshima, and Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima. SU-G-BRB-09: Kompeito-Shot: Development of a Novel Verification System for 3D Beam Alignment Including the Sag of Gantry Head. United States: N. p., 2016. Web. doi:10.1118/1.4956916.
Tsuneda, M, Nishio, T, Saito, A, Kawahara, D, Ochi, Y, Hiroshima University Hospital, Hiroshima, Hioki, K, Matsushita, K, Tanaka, S, Ozawa, S, Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Nagata, Y, Hiroshima University Hospital, Hiroshima, & Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima. SU-G-BRB-09: Kompeito-Shot: Development of a Novel Verification System for 3D Beam Alignment Including the Sag of Gantry Head. United States. doi:10.1118/1.4956916.
Tsuneda, M, Nishio, T, Saito, A, Kawahara, D, Ochi, Y, Hiroshima University Hospital, Hiroshima, Hioki, K, Matsushita, K, Tanaka, S, Ozawa, S, Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Nagata, Y, Hiroshima University Hospital, Hiroshima, and Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima. Wed . "SU-G-BRB-09: Kompeito-Shot: Development of a Novel Verification System for 3D Beam Alignment Including the Sag of Gantry Head". United States. doi:10.1118/1.4956916.
@article{osti_22649281,
title = {SU-G-BRB-09: Kompeito-Shot: Development of a Novel Verification System for 3D Beam Alignment Including the Sag of Gantry Head},
author = {Tsuneda, M and Nishio, T and Saito, A and Kawahara, D and Ochi, Y and Hiroshima University Hospital, Hiroshima and Hioki, K and Matsushita, K and Tanaka, S and Ozawa, S and Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima and Nagata, Y and Hiroshima University Hospital, Hiroshima and Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima},
abstractNote = {Purpose: High accuracy of beam axis is required for high-precision radiation therapy. It is impossible to quantitatively and directly evaluate the sagging effect of the gantry head using current methods (star-shot and Winston-Lutz tests) when the gantry head sags under the weight of MLC and X-Y jaws. We introduce a novel method “Kompeito-shot (3D star-shot)” for the verification of 3D beam alignment (3D isocentricity). This method enables direct measurement of the sagging effect. We developed the system and examined the concept of this system. Methods: The system composed of a plastic scintillator (PS), a truncated cone-shaped mirror, a plane mirror and a CCD camera. Two types of PS were compared. One consisted of a column PS (Co system), the other consisted of a column PS inserted into a barrel PS with shading film in between (Co-Ba system). The system was irradiated with a 6-MV photon beam and the scintillation light was measured using the CCD camera through the mirror system. The gantry angle was set from 270 to 300 degrees to mimic the sagging of the gantry head for evaluating the accuracy of the system. The distance between a center of PS and entrance / exit points were calculated to analyze the gantry angle. And, the calculated gantry angle and the irradiated gantry angle were compared. Results: We compared the measured image of Co system and that of Co-Ba system. Entrance and exit areas were visualized clearly. The histogram showing the difference between the calculated gantry angle and the irradiated gantry angle was fitted with a Gaussian function. Mean and standard deviation of Co-Ba system were smaller than that of Co system by one order of magnitude. Conclusion: We developed the Kompeito-shot system and evaluated the accuracy of the system. The basic concept works for the verification of 3D isocentricity.},
doi = {10.1118/1.4956916},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}