Research on the capability test and evaluation of the QuickCheck's accelerator / 中国医学装备

ABSTRACT

Objective:To give the test in cases of changing the conditions of measurement and reference value, compare the test results, and detect the capacity of QuickCheck, so as to offer reference for the daily morning check of accelerator and the evaluation of test results. Methods:Change the output dose, field size, SSD, angle of collimator and gantry angle of the accelerator, and then evaluate QuickCheck’s capacity of monitoring accelerator accordingly. Compare the field parameters measured by QuickCheck with the data from the 3D water tank. Results:When the output dose was 1 cGy higher than the reference value or 6 cGy lower than it, the field size expanded or contracted more than 2 cm simutaneouly, SSD was 2 cm higher or 1 cm lower than reference value, the collimator rotated more than 2 °, the gantry angle rotated more than 6 °, and then the test results of QuickCheck surpassed threshold. Comparing the measuring results of QuickCheck with 3D water tank, the difference between the flatness of the two was 3.84%, symmetry (G/T) 0.67%, symmetry (L/R) 0.47%and dose rate 1.2 MU/min. Conclusion:QuickCheck is rather accurate in testing the output dose, field size, angle of collimator, flatness, symmetry and dose rate, so it could meet the requirement of accelerator’s daily QA. However, its capability is relatively poor on examining SSD and the deviation of gantry angle.