Establishment of High-precision Irradiation Platform for Scientific Research and Measurement of Radiation Field

  Objective  To establish high-precision irradiation platform for scientific research based on medical accelerator and to evaluate its performance.

  Methods  Phantoms were designed referring to the petri dish commonly used in basic medical research. Irradiation platform was built on the phantoms and parameters of medical accelerator were set for the platform. Parameters for precision, stability, uniformity, and security were measured to evaluate performance of the platform.

  Results  Under the dose rate of 600 MU/minute, and when the prescription dose was between 0.5 Gy and 20 Gy, the mean dose deviation of the platform was within 2%. The mean dose deviation rose to 3% to 5% when the prescription dose was 50 Gy. Under the conditions of prescription dose being 2 Gy, and dose rate being 100, 200, 300, 600, and 1000 MU/minute, the mean dose deviation was within 2%. The difference between maximum and minimum dose of a petri dish was 0.05 Gy under the condition of 600 MU/minute dose rate and 2 Gy prescription dose; while the doses of central, side, and corner petri dishes were (2.005±0.012), (2.002±0.006), and (2.006±0.012) Gy under the same condition. The doses in the operation room were close to the natural background doses when this platform was in normal operating state. When the platform was in abnormal operating state, under the condition of 600 MU/minute dose rate and 10 Gy prescription dose, the doses in position 10, 20, 30, 50, 100, and 200 cm from the phantom and within mazes of the accelerator room were (0.055±0.002), (0.032±0.002), (0.023±0.002), (0.016±0.001), (0.006±0.001), (0.004±0.001), and (0.002±0.001) Gy, respectively.

  Conclusions  The platform can meet the requirements of most scientific researches with its high dose accuracy, high radiation field uniformity, adjustable dose rate, and high safety.