左乳腺癌保乳术后正向调强与逆向调强计划剂量及通过率比较

Dosimetry and passing rate of forward-intensity modulated radiation therapy and intensity modulated radiation therapy for left breast cancer patients with breast conserving surgery

目的比较正向调强(f-IMRT)和逆向调强(IMRT)计划用于左乳腺癌保乳术后放疗的优劣势。方法筛选11例左乳腺癌保乳术后患者为研究对象,采用Pinnacle 3治疗计划系统(TPS)建立IMRT和f-IMRT计划,分别采用TPS和Compass三维验证系统分析剂量差异及Gamma通过率,比较2种计划的优势和劣势。结果2种计划靶区(PTV)和危及器官(OAR)剂量均能满足临床需求。2种计划的心脏和左肺的5、30 Gy剂量照射的体积(V_(5)、V_(30)),左肺以及右肺平均剂量(D_(mean))比较,差异有统计学意义(P<0.05或P<0.01)。通过率分析结果显示,在3 mm/3%标准下,2种计划均通过验证,在2 mm/2%标准下,只有f-IMRT计划通过验证。f-IMRT计划PTV和OAR Gamma通过率均高于IMRT计划,差异有统计学意义(P<0.05或P<0.01)。结论f-IMR技术在保证临床剂量要求的同时,提高了计划Gamma通过率,可考虑作为常规左乳腺癌保乳术后放疗计划的首选方案。

Objective To compare the advantages and disadvantages of forward intensity modulated(f-IMRT)and intensity modulated radiation therapy(IMRT)plans for radiotherapy patients with left breast cancer undergoing breast conserving surgery.Methods Eleven patients with left breast cancer undergoing conserving surgery were selected,Pinnacle 3 Treatment Planning System(TPS)was used to design IMRT and f-IMRT planning.Dosimetric analysis was performed by TPS and the passing rate was analyzed using the Compass verification system,the strengths and weaknesses of the two plans were compared.Results The results showed that the Planning Target Volume(PTV)and Argan at Risk(OAR)doses in both groups could meet the clinical requirements.The volume of the heart and the left lung exposed to 5 Gy dose(V_(5))and exposed to 30 Gy dose(V_(30))in the two plans and the values of mean dose(D_(mean))of the left lung and the right lung were statistically significant(P<0.05 or P<0.01).The results of the passing rate analysis showed that both plans passed the verification under the standard of 3mm/3%,while only f-IMRT plan passed the verification under the standard of 2 mm/2%.The Gamma passing rates of PTV and OAR of the f-IMRT plan were significantly higher than those of the IMRT plan(P<0.05 or P<0.01).Conclusion f-IMRT technology improves the plan passing rate while ensuring the clinical dose requirements,and may be considered as the first choice for routine radiotherapy of left breast cancer undergoing conserving surgery.