摘要
目的:分析三种不同的指型电离室对医用直线加速器常用剂量率的响应特性。方法:选择三种不同的指型电离室,分别是PTW的0.6 cm3电离室和0.125 cm3电离室,IBA的0.01 cm3电离室,加速器分别在100 cGy/min～600 cGy/min的剂量率范围内,在相同的测量条件和MU下,分别测量和分析三种不同的电离室在不同的工作电压和不同能量下的剂量率响应特性。结果:剂量仪工作电压和X射线能量一定时,三种电离室的采集效率都随剂量率的增加而有一定程度的降低,X射线能量为6 MV时,三种电离室对应的剂量仪读数最大分别降低了1.90%、2.51%、1.90%,X射线能量为15 MV时,三种电离室最大分别降低了3.60%、3.57%、1.62%;当剂量率一定时,采集效率随工作电压的增加而有一定程度的升高,在工作电压较高时采集效率相对较稳定。结论:不同的指型电离室、剂量仪的工作电压以及剂量率的变化都会对采集效率有一定的影响,在临床应用中对直线加速器进行剂量测量时,需要对测量设备进行剂量率相应测试和分析以保证日常刻度和剂量验证的精度。
Objective： To analyze three different kinds of finger shape ionization chamber of medical linear accelerator is used the response of the dose rate. Methods： Choose three different kinds of finger shape ionization chamber, they are respectively 0.6 cm3 PTW ionization chamber and 0.125 cm3 ionization chamber, IBA 0.01 cm3 of ionization chamber, accelerator in 100 cGy/min-600 cGy/min, within the limits of dose rate under the same measurement conditions and MU, respectively measuring and analysis of three different kinds of ionization chamber under the different working voltage and energy of the dose rate response characteristics. Results： Dosimeter working voltage and X ray energy are constantly, three kinds of ionization chamber of collection efficiency with the increase of the dose rate have a certain degree of lower, for the 6 mv X-ray energy, three kinds of ionization chamber corresponding to the maximum dose meter readings was reduced by 1.90%, 2.51% and 1.90%, respectively, for 15 mv X-ray energy, the three largest ionization chamber was reduced by 3.60%, 3.57% and 3.60% respectively; When dose rate must be collection efficiency with the increase of the working voltage and a certain degree of rise, when the working voltage higher collection efficiency is relatively stable. Conclusions： Different finger type of ionization chamber, the working voltage of dosimeter and dose rate change will have a certain influence on collection efficiency, In the clinical applica tion of dose measurement on the linear accelerator, Need to test and analysis dose rate corresponding and the measuring equip- ment to ensure the accuracy of routine calibration and dose verification.
出处
《中国医学物理学杂志》
CSCD
2013年第5期4345-4348,4368,共5页
Chinese Journal of Medical Physics
基金
江苏省博士后科研资助计划(No.1002012C)
关键词
指型电离室
剂量仪
剂量率
工作电压
响应特性
finger shape ionization chamber
dosimer
dose rate
workingvoltage
response characteristics
