用COMPASS验证鼻咽癌调强放射治疗计划

Dosimetric verification of intensity modulated radiation therapy in nasopharyngeal carcinoma by COMPASS

目的研究COMPASS三维剂量验证系统在鼻咽癌调强剂量验证中的应用。方法 10例鼻咽癌患者,其中男性8例,女性2例;年龄37~52岁,平均年龄43岁。利用COMPASS对全部病例的调强计划进行剂量验证,比较计划系统计算结果与COMPASS实际测量结果差异的主要指标,评价靶区V95%、Dmean,腮腺Dmean,脑干、脊髓、晶状体、视神经、视交叉的D1%及各自的γ通过率。结果各靶区V95%和Dmean的差异在3%、2%以内,GTV的差异最小,为-0.97%±0.46%、-0.68%±0.24%。靶区γ通过率多在95%左右。危及器官中脊髓、脑干D1%的差异分别为4.25%±1.37%、5.50%±1.60%。晶状体、视神经、视交叉D1%的差异在2%以内。腮腺Dmean的差异在6%以内。各危及器官的γ通过率均在98%以上。结论 COMPASS能够快速、直观地分析出鼻咽癌靶区和危及器官理论和实际照射情况下的剂量差异。

Objective To study the application of COMPASS in dosimetric verification of intensity modulated radiation therapy in nasopharyngeal carcinoma. Methods A total of 10 patients with nasopharyngeal carcinoma were enrolled, which included 8 males and 2 females, aged 37- 52 years old with mean age of 43 years old. The dosimetric verification of intensity modulated radiation therapy was performed by COMPASS. The main indicators between planning system and COMPASS measurement were compared,and the target V95%, Dmean, pariotid gland Dmean, brain stem, spinal cord, lens, optic nerve, D1%of optic chiasma and their γ pass rate were evaluated. Results The difference of V95 %and Dmeanwas within 3 % and 2 %, respectively. The minimum difference of GTV was-0.97 % ± 0.46 % and- 0.68 % ± 0.24 %, respectively. The γ pass rate was about 95 % for all the target volumes. The difference of D1%of spinal cord and brain stem was 4.25 % ± 1.37 % and 5.50 % ± 1.60 %, respectively. The differences of D1%of lens, optic nerve, optic chiasma were within 2 %, and the difference of Dmeanpariotid was within 6 %. The γ pass rate was higher than 98 % for all target volumes. Conclusion It is demonstrated that the COMPASS 3D dose verification system could analyze the dose differences between theoretical and actual irradiation for nasopharyngeal carcinoma target and organ at risk.