摘要
目的检测DAVID系统对射野大小和剂量偏差的探测能力,为IMRT治疗中的实时验证提供依据。方法西门子ARTISTEZ直线加速器,选择6 MV X线,每次出束照射100 MU,确定DAVID的最小测量射野。选择最小测量射野以及5×5、10×10、20×20、30×30、40×40 cm×cm射野,改变射野大小和剂量,利用DAVID进行测量。结果最小测量射野为2 cm×2 cm。射野2×2、5×5、10×10 cm×cm,分别在X和Y方向变化1 mm,测量的偏差值在1.01%-37.62%之间。射野20×20、30×30、40×40 cm×cm,分别在X方向上变换1和2 mm,偏差在-0.94%～0.95%之间;在X方向上变换3mm,偏差分别为1.59%、1.23%和-1.13%;在Y方向上改变1 mm,偏差分别为3.07%、3.52%和-3.46%。剂量从100MU变为98MU和99MU,偏差在-1.03～-2.07%之间;变为101MU,偏差在0.86～1.28%;变为102MU,偏差在1.58～2.00%。结论对于射野2×2、5×5、10×10 cm×cm,DAVID在X和Y方向上探测射野偏差的能力均为1 mm;对于20×20、30×30、40×40 cm×cm的射野,在X和Y方向上探测偏差的能力分别为3 mm和1 mm。DAVID在Y方向上探测射野大小的偏差的能力强于X方向;对射野及剂量的增大和减小具有判断能力,若增大则偏差值为正,反之则为负。
【Objective】Test DAVID system＇s ability to detect the field Size and dose deviation,and offer basis for the real-time verification in IMRT.【Methods】We chose the Siemens ARTISTE linear accelerator and 6 MV X-ray,with a dose of 100MU provided each time the beams are ejected,and determined DAVID＇s minimal field size for measurement.We selected the minimal size and field size of 5×5,10×10,20×20,30×30 and 40×40 cm×cm,tested them by turn and change the dose,and used DAVID to measure them,respectively.【Resluts】The minimal field size was 2 cm×2 cm.We made the field size of 2×2,5×5 and 10×10 cm×cm vary 1 mm along the X-axis and Y-axis,respectively,and got results that the measured deviation values stayed within 1.01%-37.62%.Then made the field size of 20×20,30×30 and 40×40 cm×cm vary 1 mm and 2 mm along X-axis respectively,and the deviation values stayed within-0.94%～0.95%;vary 3 mm along X-axis,the 3 deviation values were 1.59%,1.23% and-1.13%;vary 1 mm along Y-axis,the deviation values were 3.07%,3.52% and-3.46%.If the dose was changed from 100 MU to 98 MU and 99 MU,deviation values were among-1.03～-2.07%;if changed to 101 MU,deviation values were among 0.86～1.28%;if changed to 102 MU,deviation values were among 1.58～2.00%.【Conclusion】 For the field size of 2×2、5×5、10×10 cm×cm,DAVID system could detect the deviation to 1 mm;for 20×20、30×30、40×40 cm×cm,it could detect the deviation to 3 mm and 1 mm along X and Y axis.All in all,DAVID system＇s ability to detect the deviation of field size along Y-axis is stronger than along X-axis.Besides,it can figure out if the field size and dose are increased or reduced： if increased,the deviation value would be positive;if reduced,negative.
出处
《中国医学工程》
2012年第12期1-2,4,共3页
China Medical Engineering
基金
军事医学计量专项课题(2011-JL2-050)
