Szweda Hubert, Graczyk Kinga, Radomiak Dawid, Matuszewski Krzysztof, Pawałowski Bartosz
Dosimetry Department of Medical Equipment, The Maria Skłodowska-Curie Greater Poland Cancer Centre, Poznań, Poland.
Wydział Fizyki, Uniwersytet im. Adama Mickiewicza w Poznaniu, Poznań, Poland.
Rep Pract Oncol Radiother. 2020 May-Jun;25(3):351-354. doi: 10.1016/j.rpor.2020.03.003. Epub 2020 Mar 4.
One of the most important test in every quality assurances process of medical linear accelerators is the Winston-Lutz test, allowing an evaluation of the treatment isocentre in the light of uncertainty of the position of the collimator, the gantry and the couch.
The purpose of this work was analysis of the results of the Winston-Lutz test performed with three different phantoms for two different accelerators.
Measurements were performed on two Varian machines: TrueBeam equipped with aS1200 EPID and TrueBeam equipped with aS1000 EPID. During the study three different phantoms dedicated for verification of the radiation isocentre were used: PTW Isoball, AQUILAB Isocentre Phantom and Varian Isocentre Cube. Analysis of the DICOM images was performed in Artiscan software.
For TrueBeam with as1200 EPID, gantry MV isocentre was about 0.18 mm larger for Varian Isocentre Cube than for two other phantoms used in this study. The largest variability of this parameter was observed for the couch. The results differed to 1.16 mm. For TrueBeam with as1000 EPID, results for collimator isocentre with PTW Isoball phantom were about 0.10 mm larger than for two other phantoms. For the gantry, results obtained with Varian Isocentre Cube were 0.21 mm larger.
The obtained results for all three phantoms are within the accepted tolerance range. The largest differences were observed for treatment couch, which may be related to the phantom mobility during couch movement.
在医用直线加速器的每个质量保证过程中，最重要的测试之一是温斯顿 - 卢茨测试，该测试可根据准直器、机架和治疗床位置的不确定性来评估治疗等中心。
这项工作的目的是分析使用三种不同模体对两种不同加速器进行温斯顿 - 卢茨测试的结果。
在两台瓦里安机器上进行测量：配备aS1200 EPID的TrueBeam和配备aS1000 EPID的TrueBeam。在研究过程中，使用了三种不同的用于验证辐射等中心的模体：PTW等球体、AQUILAB等中心模体和瓦里安等中心立方体。在Artiscan软件中对DICOM图像进行分析。
对于配备aS1200 EPID的TrueBeam，瓦里安等中心立方体的机架兆伏等中心比本研究中使用的其他两种模体大约大0.18毫米。该参数在治疗床方面的变异性最大。结果相差1.16毫米。对于配备aS1000 EPID的TrueBeam，使用PTW等球体模体时准直器等中心的结果比其他两种模体大约大0.10毫米。对于机架，使用瓦里安等中心立方体获得的结果大0.21毫米。
所有三种模体获得的结果均在可接受的公差范围内。在治疗床方面观察到的差异最大，这可能与治疗床移动过程中模体的移动性有关。
