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Title: Development of a QA phantom and automated analysis tool for geometric quality assurance of on-board MV and kV x-ray imaging systems

Abstract

The medical linear accelerator (linac) integrated with a kilovoltage (kV) flat-panel imager has been emerging as an important piece of equipment for image-guided radiation therapy. Due to the sagging of the linac head and the flexing of the robotic arms that mount the x-ray tube and flat-panel detector, geometric nonidealities generally exist in the imaging geometry no matter whether it is for the two-dimensional projection image or three-dimensional cone-beam computed tomography. Normally, the geometric parameters are established during the commissioning and incorporated in correction software in respective image formation or reconstruction. A prudent use of an on-board imaging system necessitates a routine surveillance of the geometric accuracy of the system like the position of the x-ray source, imager position and orientation, isocenter, rotation trajectory, and source-to-imager distance. Here we describe a purposely built phantom and a data analysis software for monitoring these important parameters of the system in an efficient and automated way. The developed tool works equally well for the megavoltage (MV) electronic portal imaging device and hence allows us to measure the coincidence of the isocenters of the MV and kV beams of the linac. This QA tool can detect an angular uncertainty of 0.1 deg. of themore » x-ray source. For spatial uncertainties, such as the source position, the imager position, or the kV/MV isocenter misalignment, the demonstrated accuracy of this tool was better than 1.6 mm. The developed tool provides us with a simple, robust, and objective way to probe and monitor the geometric status of an imaging system in a fully automatic process and facilitate routine QA workflow in a clinic.« less

Authors:
; ;  [1]
  1. Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305 (United States)
Publication Date:
OSTI Identifier:
21120653
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 35; Journal Issue: 4; Other Information: DOI: 10.1118/1.2885719; (c) 2008 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ACCURACY; COMMISSIONING; COMPUTER CODES; COMPUTERIZED TOMOGRAPHY; IMAGE PROCESSING; IMAGES; LINEAR ACCELERATORS; PHANTOMS; QUALITY ASSURANCE; RADIOTHERAPY; X RADIATION; X-RAY SOURCES; X-RAY TUBES

Citation Formats

Weihua, Mao, Lee, Louis, and Lei, Xing. Development of a QA phantom and automated analysis tool for geometric quality assurance of on-board MV and kV x-ray imaging systems. United States: N. p., 2008. Web. doi:10.1118/1.2885719.
Weihua, Mao, Lee, Louis, & Lei, Xing. Development of a QA phantom and automated analysis tool for geometric quality assurance of on-board MV and kV x-ray imaging systems. United States. https://doi.org/10.1118/1.2885719
Weihua, Mao, Lee, Louis, and Lei, Xing. 2008. "Development of a QA phantom and automated analysis tool for geometric quality assurance of on-board MV and kV x-ray imaging systems". United States. https://doi.org/10.1118/1.2885719.
@article{osti_21120653,
title = {Development of a QA phantom and automated analysis tool for geometric quality assurance of on-board MV and kV x-ray imaging systems},
author = {Weihua, Mao and Lee, Louis and Lei, Xing},
abstractNote = {The medical linear accelerator (linac) integrated with a kilovoltage (kV) flat-panel imager has been emerging as an important piece of equipment for image-guided radiation therapy. Due to the sagging of the linac head and the flexing of the robotic arms that mount the x-ray tube and flat-panel detector, geometric nonidealities generally exist in the imaging geometry no matter whether it is for the two-dimensional projection image or three-dimensional cone-beam computed tomography. Normally, the geometric parameters are established during the commissioning and incorporated in correction software in respective image formation or reconstruction. A prudent use of an on-board imaging system necessitates a routine surveillance of the geometric accuracy of the system like the position of the x-ray source, imager position and orientation, isocenter, rotation trajectory, and source-to-imager distance. Here we describe a purposely built phantom and a data analysis software for monitoring these important parameters of the system in an efficient and automated way. The developed tool works equally well for the megavoltage (MV) electronic portal imaging device and hence allows us to measure the coincidence of the isocenters of the MV and kV beams of the linac. This QA tool can detect an angular uncertainty of 0.1 deg. of the x-ray source. For spatial uncertainties, such as the source position, the imager position, or the kV/MV isocenter misalignment, the demonstrated accuracy of this tool was better than 1.6 mm. The developed tool provides us with a simple, robust, and objective way to probe and monitor the geometric status of an imaging system in a fully automatic process and facilitate routine QA workflow in a clinic.},
doi = {10.1118/1.2885719},
url = {https://www.osti.gov/biblio/21120653}, journal = {Medical Physics},
issn = {0094-2405},
number = 4,
volume = 35,
place = {United States},
year = {Tue Apr 15 00:00:00 EDT 2008},
month = {Tue Apr 15 00:00:00 EDT 2008}
}