Study on performance of morning check device in the application of daily quality control of medical linear accelerator / 中国医学装备

ABSTRACT

Objective: To evaluate the performance of morning check device by comparing the dosimetric parameters of medical linear accelerators measured by radiation dosimeter, 3D water phantom and morning check device. Methods:The dosimetric parameters of the linear accelerator were measured and adjusted by using dosimeter and 3D water phantom so as firstly to ensure the stability of the beam system of accelerators. After the baseline was established, the dosimeter, 3D water phantom and morning check device were applied to measure central axis output dosage, and flatness and symmetry of the field, respectively. And then the data were collected and differences of the results were compared. And compared the results of morning check device with the baseline to evaluate performance of morning check device. Results: The results measured of morning check device were close to those measured by 3D water phantom. The maximum deviations of central axis output (CAX), flatness along LR direction, flatness along GT direction, symmetry along LR direction and symmetry along GT direction measured by morning check device were 0.87%, 0.96%, 0.48%, 0.40% and 0.59%, respectively, which were in the range of 3% and could meet the requirement of AAPM TG-142 report. Conclusion: It shows that the morning check device is effective and feasible to be used for daily quality control of linear accelerators, and it can be used as tool of daily quality control.