Abstract：Objective To explore the effects of air gap, radiation filtering mode, calculation model and beam inclination on skin dose
under different compensation film thickness based on the combined imaging uRT-TPS model. Methods 17 phantom models were
constructed by changing the size of air gap (0, 2, 4 and 6 mm) and the thickness of compensation film (0, 5, 10, 15 and 20 mm)
using a solid water layer plate. In uRT-TPS, 248 treatment plans were designed for these 17 phantom models by changing three types
of variables: ray filtering mode (FF and FFF), calculation model (MC and Convolution) and beam inclination (0°-80°), under the
condition that the average dose of all planned target areas reached 1000 cGy, the average dose of skin layer (Da or Dt) and the dose
enhancement factor of skin layer (div) were obtained. Results The thickness of compensation film was within 0-10 mm, and Dt
increases with the increase of thickness. When the compensation film was 5 mm, the Dt of 4 mm space gap was the largest, and the
div of 0 mm space gap was the smallest. Without compensation film, the value of Da under FFF mode was higher than that under FF
mode, and the value of Da under FF and MC conditions was higher. With compensation film, div under FF and MC conditions was
low. Div increases with the increase of beam inclination, and div value in FF mode decreases with the increase of compensation film,
while div value in FFF mode increases with the increase of compensation film. Conclusion In the radiotherapy of superficial tumors,
the skin dose is affected by five factors: compensation film thickness, space gap, radiation filtering mode, calculation model and beam
angle. Clinical practice should be flexible to adjust according to the needs, and reduce the skin dose as much as possible.
桂龙刚，李军. 空气间隙、射线过滤模式、计算模型和
光束倾角在不同补偿膜厚度条件下
对皮肤剂量的影响[J]. 中国医疗设备, 2023, 38(12): 46-50.
GUI Longgang, LI Jun. Effects of Air Gap, Radiation Filtering Mode, Calculation Model and Beam Inclination Angle
on Skin Dose Under Different Compensation Film Thickness. China Medical Devices, 2023, 38(12): 46-50.
