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| The Results and Evaluation of the Quick Check Examination on the Linear Accelerator in One Year |
| LI Yu, XU Hui-jun, ZHANG Su-jing |
| Oncology Radiotheraphy Center of 302 Military Hospital, Beijing 100039 China |
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Abstract Objective To collect data about the QUICK CHECK on a linear accelerator's field parameters, analyze the results, and evaluate the consistency of central axis dose, the flatness, symmetry, radiation quality and dose rate of the accelerator's fields. Methods During February 2012 and February 2013, the accelerator worked normally for 216 days and had breakdown for 47 days. We utilized QUICK CHECK to examine the two fields of 10 cm×10 cm and 20 cm×20cm and used the check results as a standard for following detection. We used QUICK CHECK to examine the linear accelerator for 216 times. Detected parameters included central axis dose, flatness, symmetry (along directions of (gun-target) G/T and L/R (left-right)), radiation quality and dose rate. We collected and analyzed the detection data, and then evaluated the stability of the accelerator. Results For the field of 10 cm×10 cm, the central axis dose was (100 ±2.3) MU, and detected results exceeded 2% for 11 times (5.09%). The detection value of flatness was (100 ±2.6)%, and the results exceeded 2% for 4 times (1.85%). The detection value of symmetry (direction of G/T) was (100 ±1.4)%, the value of symmetry (direction of L/R) was (100 ±2.7)%, and 4 (1.85%) of the results exceeded 2%. The detection value of radiation quality was (100 ±2.79)%, and exceeded 2% for 3 times (1.39%). The detection value of dose rate was 300 ±11.2 MU/min. For the field of 20 cm×20 cm, the central axis dose was (100 ±2.1) MU, and detected results exceeded 2% for 11 times (5.09%). The detection value of flatness was (100 ±1.2)%. The value of symmetry (direction of G/T) was (100 ±0.27)%, the one of symmetry (direction of L/R) was (100 ±1.27)%, radiation quality (100 ±0.35%). Conclusion The qualified rate of central axis dose was 94.91%, flatness 98.15%, symmetry 100%, radiation quality 100% and dose rate 100%. Except for the central axis dose, the qualified rates of consistency of the parameters were all above 98%. Therefore the accelerator's stability was excellent.
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Received: 17 April 2013
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