两种不同调强放射治疗中全脑放射治疗的海马和下丘脑-垂体轴剂量学比较研究  

Study on the dosimetric comparison of hippocampus,HT-P axis of whole brain radiotherapy between two different kinds of IMRT

作　　者：李伶 李淑慧 徐祖敏 梁玉新 周凌宏[1] LI Ling;LI Shu-hui;XU Zu-min(School of Biomedical Engineering,Southern Medical University,Guangdong 510515,China)

机构地区：[1]南方医科大学生物医学工程学院,广东广州510515 [2]广东医科大学附属医院肿瘤医院放疗机房,广东湛江524001

出　　处：《中国医学装备》2023年第5期6-11,共6页China Medical Equipment

基　　金：广东医科大学科研基金(GDMUM2019040)“图像引导放射治疗产生的辐射剂量对海马剂量影响研究”;湛江市科技计划(2022B01041)“基于直线加速器全脑全脊髓保护海马放射治疗剂量学研究”。

摘　　要：目的:比较3个非共面全弧容积旋转调强放射治疗(VMAT)与9野共面调强放射治疗(IMRT)在脑转移患者全脑照射保护海马和下丘脑-垂体轴计划中的剂量分布。方法:选取在医院进行放射治疗的12例肺癌脑转移患者图像资料。其中8例患者预防性颅脑照射(PCI)为36 Gy/18次,脑转移病灶推量(SIB)照射总剂量为54 Gy/18次;另4例患者只做了总剂量为36 Gy/18次的PCI治疗。每例患者分别设计3个非共面全弧VMAT(3A-VMAT)及9共面野IMRT(9F-IMRT)两种治疗计划,模拟设计海马和下丘脑-垂体(HT-P)轴区域的保留方法。放射治疗计划未实施到患者体内。评价两种计划适形性指数(CI)、均匀性指数(HI)、靶区覆盖(TC)、γ通过率、海马、下丘脑及垂体剂量。结果:(1)VMAT计划剂量SIB照射的CI、HI和TC分别为0.972、0.059和97.19%;IMRT计划剂量分别为0.955、0.083和95.45%,两种计划的HI比较差异有统计学意义(Z=3.524,P<0.05);(2)VMAT计划剂量全脑放射治疗(WBRT)的CI、HI和TC与IMRT计划比较,差异均有统计学意义(t=-5.007,t=-4.056,t=10.025;P<0.05);(3)VMAT计划左侧海马和右侧海马剂量最大辐射剂量(D_(max))、平均辐射剂量(D_(mean))和等效2 Gy剂量(EQD2)与IMRT计划比较,差异均有统计学意义(Z_(左侧海马)=-2.432,Z=-3.059,Z=2.432;Z_(右侧海马)=-3.059,Z=2.353,Z=-2.589;P<0.05);(4)VMAT计划HT-P D_(max)、HT-P D_(mean)和机器跳数(MU)值与IMRT计划比较,差异有统计学意义(Z=-3.059,Z=2.904,Z=-3.059;P<0.05)。VMAT计划与IMRT计划的γ通过率比较差异无统计学意义。结论:3个非共面全弧VMAT计划靶区剂量分布明显优于9野共面IMRT,对海马和下丘脑-垂体轴的保护VMAT也有较大优势。两种IMRT技术在全脑放射治疗同时保护海马和下丘脑-垂体轴均具有可行性,但需要进行前瞻性的神经系统、内分泌结果和安全性分析。Objective:To compare the dose distributions between 3-non coplanar volumetric-modulated arc therapy(VMAT)and 9-feiled coplanar intensity-modulated radiation therapy(IMRT)in the protection plan for hippocampus,hypothalamus-pituitary(HT-P)axis of patients with brain metastases of tumor who received whole brain radiotherapy.Methods:The image data of twelve patients with brain metastasis of lung cancer who underwent radiotherapy at hospital were selected.The prophylactic cranial irradiation(PCI)and the exposed total dose of simultaneous integrated boost(SIB)of the lesion of the brain metastases of 8 patients respectively were 36Gy/18 F and 54Gy/18 F.The other 4 patients only received PCI treatment which total dose was 36 Gy/18 F.The 3-non coplanar VMAT and 9-feiled IMRT were respectively designed for each case,and the retention method of the regions of the hippocampus and the HT-P axis was simulated.Radiotherapy plan did not be implemented in the body of patients.The conformity index(CI),homogeneity index(HI),target coverage(TC),γpassing rates,and the doses of hippocampus,hypothalamus and pituitary between the two kinds of plans were evaluated.Results:①The CI,HI and TC of the SIB expose of planned dose of VMAT respectively were 0.972,0.059 and 97.19%,and the doses of IMRT plan respectively were 0.955,0.083 and 95.45%,and the difference of HI between the two kinds of plans was significant(Z=3.524,P>0.05).②The differences of CI,HI and TC of whole brain radiation therapy(WBRT)between VMAT plan dose and IMRT plan were significant(t=-5.007,t=-4.056,t=10.025,P<0.05).③The differences of D_(max),D_(mean)and equivalent 2Gy dose(EQD2)of left and right side of hippocampal doses between VMAT plan and IMRT plan were significant(Z_(left hippocampus)=-2.432,Z=-3.059,Z=2.432,Z_(right hippocampus)=-3.059,Z=2.353,Z=-2.589,P<0.05),respectively.④The differences of HT-P D_(max),HT-P D_(mean)and machine unit(MU)values between VMAT plan and IMRT plan were significant(Z=-3.059,Z=2.904,Z=-3.059,P<0.05).There was no statistically sig

关 键 词：全脑放射治疗(WBRT) 脑转移瘤 海马 调强放射治疗(IMRT) 容积旋转调强放射治疗(VMAT) 

分 类 号：R814.2[医药卫生—影像医学与核医学]