APPLICATION OF IMAGE ANALYSIS METHODS FOR ISOCENTER QUALITY ASSURANCE IN RADIOTHERAPY

Michał Niedźwiecki; Monika Tomaszuk; Damian Kabat; Zbigniew Latała; Krzysztof Rzecki; Zbislaw Tabor

doi:10.5566/ias.1631

Authors

Michał Niedźwiecki Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland
Monika Tomaszuk Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Kraków Branch, Garncarska 11, 31-115 Kraków, Poland
Damian Kabat Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Kraków Branch, Garncarska 11, 31-115 Kraków, Poland
Zbigniew Latała Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland
Krzysztof Rzecki Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland
Zbislaw Tabor Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland

DOI:

https://doi.org/10.5566/ias.1631

Keywords:

fiducials, isocenter, projection images, radiotherapy

Abstract

One of the major procedures for testing the geometrical accuracy of devices used in radiotherapy treatments is the test of the geometrical position of the radiation isocenter. The importance of the test reflects the fact that geometrical position of the radiation isocenter generally affects the tumor targeting. At present the geometric accuracy is assessed with the Winston-Lutz test which checks the position of an image of a ball marker with the respect to the center of the radiation field as projected on a detector plane. Obviously, determination of coordinates of a single marker is not sufficient to fully account for a complicated geometry of a therapeutic device. The purpose of the study was to design a new image analysis tool to better determine the isocenter. The proposed automated procedure for determining isocenter position uses projection data acquired for a special cube phantom. The projection images of a phantom are acquired for various angles of rotation of the gantry. A procedure is proposed to extract some geometric characteristics of a therapeutic device from the projection images.

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