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Title: SU-E-T-68: A Quality Assurance System with a Web Camera for High Dose Rate Brachytherapy

Abstract

Purpose: The purpose of this work was to develop a quality assurance (QA) system for high dose rate (HDR) brachytherapy to verify the absolute position of an 192Ir source in real time and to measure dwell time and position of the source simultaneously with a movie recorded by a web camera. Methods: A web camera was fixed 15 cm above a source position check ruler to monitor and record 30 samples of the source position per second over a range of 8.0 cm, from 1425 mm to 1505 mm. Each frame had a matrix size of 480×640 in the movie. The source position was automatically quantified from the movie using in-house software (built with LabVIEW) that applied a template-matching technique. The source edge detected by the software on each frame was corrected to reduce position errors induced by incident light from an oblique direction. The dwell time was calculated by differential processing to displacement of the source. The performance of this QA system was illustrated by recording simple plans and comparing the measured dwell positions and time with the planned parameters. Results: This QA system allowed verification of the absolute position of the source in real time. The mean differencemore » between automatic and manual detection of the source edge was 0.04 ± 0.04 mm. Absolute position error can be determined within an accuracy of 1.0 mm at dwell points of 1430, 1440, 1450, 1460, 1470, 1480, 1490, and 1500 mm, in three step sizes and dwell time errors, with an accuracy of 0.1% in more than 10.0 sec of planned time. The mean step size error was 0.1 ± 0.1 mm for a step size of 10.0 mm. Conclusion: This QA system provides quick verifications of the dwell position and time, with high accuracy, for HDR brachytherapy. This work was supported by the Japan Society for the Promotion of Science Core-to-Core program (No. 23003)« less

Authors:
; ; ; ; ; ; ; ;  [1]
  1. Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka-shi, Osaka (Japan)
Publication Date:
OSTI Identifier:
22545198
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; ACCURACY; BRACHYTHERAPY; CAMERAS; COMPUTER CODES; DOSE RATES; ERRORS; IRIDIUM 192; PERFORMANCE; QUALITY ASSURANCE; RADIATION DOSES; VERIFICATION

Citation Formats

Ueda, Y, Hirose, A, Oohira, S, Isono, M, Tsujii, K, Miyazaki, M, Kawaguchi, Y, Konishi, K, and Teshima, T. SU-E-T-68: A Quality Assurance System with a Web Camera for High Dose Rate Brachytherapy. United States: N. p., 2015. Web. doi:10.1118/1.4924429.
Ueda, Y, Hirose, A, Oohira, S, Isono, M, Tsujii, K, Miyazaki, M, Kawaguchi, Y, Konishi, K, & Teshima, T. SU-E-T-68: A Quality Assurance System with a Web Camera for High Dose Rate Brachytherapy. United States. doi:10.1118/1.4924429.
Ueda, Y, Hirose, A, Oohira, S, Isono, M, Tsujii, K, Miyazaki, M, Kawaguchi, Y, Konishi, K, and Teshima, T. Mon . "SU-E-T-68: A Quality Assurance System with a Web Camera for High Dose Rate Brachytherapy". United States. doi:10.1118/1.4924429.
@article{osti_22545198,
title = {SU-E-T-68: A Quality Assurance System with a Web Camera for High Dose Rate Brachytherapy},
author = {Ueda, Y and Hirose, A and Oohira, S and Isono, M and Tsujii, K and Miyazaki, M and Kawaguchi, Y and Konishi, K and Teshima, T},
abstractNote = {Purpose: The purpose of this work was to develop a quality assurance (QA) system for high dose rate (HDR) brachytherapy to verify the absolute position of an 192Ir source in real time and to measure dwell time and position of the source simultaneously with a movie recorded by a web camera. Methods: A web camera was fixed 15 cm above a source position check ruler to monitor and record 30 samples of the source position per second over a range of 8.0 cm, from 1425 mm to 1505 mm. Each frame had a matrix size of 480×640 in the movie. The source position was automatically quantified from the movie using in-house software (built with LabVIEW) that applied a template-matching technique. The source edge detected by the software on each frame was corrected to reduce position errors induced by incident light from an oblique direction. The dwell time was calculated by differential processing to displacement of the source. The performance of this QA system was illustrated by recording simple plans and comparing the measured dwell positions and time with the planned parameters. Results: This QA system allowed verification of the absolute position of the source in real time. The mean difference between automatic and manual detection of the source edge was 0.04 ± 0.04 mm. Absolute position error can be determined within an accuracy of 1.0 mm at dwell points of 1430, 1440, 1450, 1460, 1470, 1480, 1490, and 1500 mm, in three step sizes and dwell time errors, with an accuracy of 0.1% in more than 10.0 sec of planned time. The mean step size error was 0.1 ± 0.1 mm for a step size of 10.0 mm. Conclusion: This QA system provides quick verifications of the dwell position and time, with high accuracy, for HDR brachytherapy. This work was supported by the Japan Society for the Promotion of Science Core-to-Core program (No. 23003)},
doi = {10.1118/1.4924429},
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}
}