TY - JOUR
T1 - Mechanical quality assurance using light field for linear accelerators with camera calibration
AU - Park, Kwangwoo
AU - Choi, Wonhoon
AU - Keum, Ki Chang
AU - Lee, Ho
AU - Yoon, Jeongmin
AU - Lee, Chang Geol
AU - Lee, Ik Jae
AU - Cho, Jaeho
N1 - Publisher Copyright:
© 2016 Associazione Italiana di Fisica Medica.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2016/2/1
Y1 - 2016/2/1
N2 - Mechanical Quality Assurance (QA) is important to assure spatially precise delivery of external-beam radiation therapy. As an alternative to the conventional-film based method, we have developed a new tool for mechanical QA of LINACs which uses a light field rather than radiation. When light passes through the collimator, a shadow is projected onto a piece of translucent paper and the resulting image is captured by a digital camera via a mirror. With this method, we evaluated the position of the LINAC isocenter and the accuracy of the gantry, collimator, and couch rotation. We also evaluated the accuracy of the digital readouts of the gantry, collimator, and couch rotation. In addition, the treatment couch position indicator was tested. We performed camera calibration as an essential pre-requisite for quantitative measurements of the position of isocenter, the linear motion of the couch, and the rotation angles of the gantry and collimator. Camera calibration reduced the measurement error to submillimeter based on uncertainty in pixel size of the image, while, without calibration, the measurement error of up to 2 mm could occur for an object with a length of 5 cm.
AB - Mechanical Quality Assurance (QA) is important to assure spatially precise delivery of external-beam radiation therapy. As an alternative to the conventional-film based method, we have developed a new tool for mechanical QA of LINACs which uses a light field rather than radiation. When light passes through the collimator, a shadow is projected onto a piece of translucent paper and the resulting image is captured by a digital camera via a mirror. With this method, we evaluated the position of the LINAC isocenter and the accuracy of the gantry, collimator, and couch rotation. We also evaluated the accuracy of the digital readouts of the gantry, collimator, and couch rotation. In addition, the treatment couch position indicator was tested. We performed camera calibration as an essential pre-requisite for quantitative measurements of the position of isocenter, the linear motion of the couch, and the rotation angles of the gantry and collimator. Camera calibration reduced the measurement error to submillimeter based on uncertainty in pixel size of the image, while, without calibration, the measurement error of up to 2 mm could occur for an object with a length of 5 cm.
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U2 - 10.1016/j.ejmp.2016.01.003
DO - 10.1016/j.ejmp.2016.01.003
M3 - Article
C2 - 26833362
AN - SCOPUS:84960325704
VL - 32
SP - 398
EP - 402
JO - Physica Medica
JF - Physica Medica
SN - 1120-1797
IS - 2
ER -