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目的分析电子射野影像系统(EPID)用于调强放射治疗计划剂量验证的准确性。方法选择2014年南通市第一人民医院住院行放射治疗宫颈癌术后患者10例,年龄45~71岁,中位年龄56岁。采用7野均分(0°、52°、104°、156°、208°、260°、310°7个角度)进行计划设计及剂量分布计算,获取归零野和实际野验证时叶片位移偏移、射野通过率,并将EPID归零野验证结果与PTW电离室矩阵归零野验证的射野通过率结果进行比较。结果EPID归零野和实际野验证获得的叶片偏移1 mm以内百分比数值的绝对值差异不大,但在208°、260°及310°3个角度差异有统计学意义。射野验证通过率在0°、52°时差异无统计学意义,而104°、156°、208°、260°、310°时差异有统计学意义。EPID归零野验证时获得的射野通过率与PTW电离室矩阵的验证结果差异无统计学意义。结论 EPID可以应用于调强计划的验证。
Objective To analyze the accuracy of electronic dose imaging system (EPID) used in intensity-modulated radiation therapy planning dose verification. Methods In 2014, Nantong First People’s Hospital radiotherapy for cervical cancer patients after surgery in 10 patients, aged 45 to 71 years, the median age of 56 years. The program design and dose distribution calculation were carried out using 7 field average (0 °, 52 °, 104 °, 156 °, 208 °, 260 ° and 310 °) to obtain the leaf displacement Pass and field pass rate, and compare the result of EPID zero-field verification with the field-pass rate of PTW ionization chamber matrix. Results There was no significant difference in the absolute values of the percentage of leaves within 1 mm of the leaf deviations of EPID obtained from the field trials and field trials. However, the differences between the three angles of 208 °, 260 ° and 310 ° were statistically significant. There was no significant difference in pass rate between 0 ° and 52 °, while there was significant difference between 104 °, 156 °, 208 °, 260 ° and 310 °. There was no significant difference in the pass-through rate between the EPID and the PTW ionization chamber matrix. Conclusion EPID can be applied to the verification of IMRT.