非小细胞肺癌同期放化疗后重度急性放射性肺炎的预测模型研究北大核心CSCD

目的 利用剂量体积直方图（DVH）参数建立Logistic剂量反应及Lyman-Kutcher-Burman正常组织并发症概率（LKB-NTCP）模型,并评估其对非小细胞肺癌同期放化疗后重度急性放射性肺炎（SARP）的预测价值.方法 搜集2006-2010年间行三维适形放疗同期化疗的147例非小细胞肺癌患者资料.按美国RTOG毒性评价标准定义超过3级的ARP为SARP.根据DVH剂量学信息建立Logistic剂量反应模型和LKB-NTCP模型.结果 SARP发生率为9.5％（14/147）.Logistic剂量反应模型参数：常数b0=-6.66、b1=0.252,TD50=26.43 Gy,γ50=1.67;模型曲线在17 Gy以下相对平坦,17～18 Gy处变为陡峭,SARP风险增大.LKB-NTCP模型参数：体积效应因子n=0.87±0.40,曲线斜率倒数m=0.27 ±0.10,TD50（1）=（29.5±8.0）Gy;Logistic回归及ROC分析均发现此参数下计算出NTCP值对SARP有良好预测价值（P=0.013、0.019）.结论 NTCP值对SARP的预测价值优于简单剂量参数,2个模型曲线均提示最大限制剂量在约17 Gy.     

非小细胞肺癌同期放化疗后重度急性放射性肺炎的预测因素

目的 评价剂量体积直方图参数及临床因素对非细胞肺癌三维适形放疗同期化疗后急性重度放射性肺炎(SARP)的预测价值。方法 回顾分析2006-2010年行三维适形放疗同期化疗的非小细胞肺癌 147例病例资料。对有无SARP的剂量学参数行成组t检验,对有差异的和临床因素行Logistic法多因素预测分析。用受试者工作特征(ROC)曲线分析各剂量学因素的预测价值,Pearson法分析剂量学数据间相关性并从剂量学参数中提取有代表性因子。结果 全组患者SARP发生率为9.5%。平均肺剂量(MLD)、V₂₀、V₃₀、V₄₀、V₅₀与SARP发生相关(χ²=4.87~6.84,P=0.009~0.025)。控制SARP发生率≤5%时的界值分别为MLD≤16.77 Gy,V₂₀≤34.15%, V₃₀≤23.62%, V₄₀≤18.57%, V₅₀≤13.02%, 其敏感性、特异性、ROC曲线下面积分别为78.0%、48.1%、0.678,42.9%、82.0%、0.661,78.6%、52.9%、0.667,71.4%、61.7%、0.677,57.1%、67.7%、0.651。因子分析显示可考虑选取MLD、V₂₀、V₃₀中的1个或2个,V₄₀、V₅₀中的1个用于预测SARP。肿瘤位于右中下肺者SARP发生率高于其他部位(22.2%∶6.7%,χ²=6.19,P=0.023)。结论 MLD、V₂₀、V₃₀、V₄₀、V₅₀可用于放射性肺炎预测,但单个预测价值不佳,要多种参数联合使用。肿瘤位于右肺中下叶者放疗后发生SARP危险性较肿瘤位于其他部位者高。     

CBCT配准前后的肺癌调强放疗计划比较研究

目的 对肺肿瘤利用CBCT图像配准确定PTV外扩距离,与常规调强放疗计划进行比较并行差异评估。方法 选10例肺肿瘤患者每周1次肺部CBCT,每次放疗前后分别进行。对数据依据二参数法得到三维方向外扩距离重新勾画靶区制定计划(校正后),并与原计划(校正前)双肺、脊髓的DVH参数、PTV体积和剂量以及NTCP进行比较,差异行协方差分析或Wilcoxson符号秩检验。结果 经CBCT校正前后计划的PTV最大剂量、最小剂量、平均剂量,双肺V₅、V₁₀、V₂₀、V₃₀、V₅₀均相似(P=0.242~0.663),校正后PTV体积、双肺所受平均剂量有优势(P=0.049、0.035),校正后NTCP随V₅、V₁₀、V₂₀增加有下降趋势(P=0.146、0.053、0.000)。结论 利用CBCT技术校正后可缩小PTV体积,减少双肺平均受量,降低NTCP,有可能提高PTV剂量,从而提高肺癌放疗局部控制率。     

利用VMAT模型基于知识IMRT计划半自动优化

目的 利用RapidPlan系统评估VMAT模型用于基于知识优化固定野动态IMRT计划可行性及剂量学特点。方法 ①利用81例优质直肠癌术前同步推量VMAT计划训练DVH预测模型并进行统计学验证;②复制经临床确认的10例相同处方IMRT计划,保持布野及能量等参数不变,用上述模型自动生成新的优化参数及各野动态MLC序列;③利用相同剂量计算方法计算原计划及新计划的绝对剂量以排除版本间差异;④将计划归一至相近靶区剂量覆盖后对各剂量学参数行统计学分析。结果 在相似靶区剂量均匀性及覆盖率基础上,RapidPlan计划显著且大幅减低了膀胱受量[D_50%降低9.01 Gy (P=0.000),D_mean降低8.08 Gy (P=0.005)]和股骨头受量[D_50%降低4.20 Gy (P=0.000),D_mean降低3.84 Gy (P=0.005)],但平均总跳数也显著高于原计划[(1211±99) MU比(771±79) MU,P=0.000]且劈野数更多。基于知识的半自动优化导致高剂量热区明显增加,但D_2%相近(52.54 Gy∶52.71 Gy,P=0.239)。结论 VMAT模型可用于基于知识IMRT半自动优化以提高效率并改善OAR保护,但高剂量热区需进一步人工干预。     

宫颈癌常规放疗联合腔内三维放疗的初步研究

目的 探讨体外放疗联合CT影像为基础近距离放疗的宫颈癌患者DVH参数和治疗结果间关系。方法 2008—2011年间18例接受根治性放疗的Ⅱ_B—Ⅲ_B期宫颈癌患者进行了常规放疗加CT为基础的近距离三维放疗。观察两种放疗相加的高危CTV的D₉₀和直肠、膀胱的D_{2 cm³} 、D_{1 cm³} ,采用EQD₂进行剂量叠加。同时随访患者不良反应。结果 A点剂量为(93.0±5.5) Gy,高危CTV D₉₀为(73.6±11.9) Gy。患者中位随访时间为26个月,无复发病例。8例患者出现轻中度直肠晚期反应,其直肠D_{2 cm³} 、D_{1 cm³} 均高于无反应者[(87.4±3.8) Gy∶(75.8±7.4) Gy,P=0.004;(96.4±6.6) Gy∶(80.5±7.1) Gy,P=0.001]。结论 CT引导的宫颈癌三维近距离放疗高危CTV D₉₀剂量比文献报道略低,直肠D_{2 cm³} 建议<75 Gy。     

三维放疗前后血清心肌酶谱变化与心脏体积剂量相关性分析

目的 探讨胸部肿瘤患者三维放疗前后血清心肌酶谱改变与心脏体积剂量的相关性。方法 102例胸部肿瘤患者(肺癌 68例、食管癌 34例)放疗前后检测血清天冬氨酸氨基转移酶(AST)、肌酸激酶(CK)、CK同工酶(CK-MB)、乳酸脱氢酶(LDH)及α-羟丁酸脱氢酶(α-HBDH)水平。放疗前后各种酶水平比较行配对t检验,组间比较行成组t检验。采用剂量体积直方图(DVH)参数\[心脏接受≥x Gy照射体积占总体积百分比(Vx)\]评价心脏体积剂量,各种酶与DVH参数相关性行Pearson法分析。结果 放疗后血清AST、CK-MB、LDH、α-HBDH水平较放疗前明显增高(19.42∶27.89、14.72∶19.57、178.80∶217.57、140.32∶176.25,t=－3.39~－6.92,P均=0.000)。调强放疗前后AST变化与 V₂₀、V₂₅、V₃₀相关(r=0.302~0.431,P=0.039~0.003),CK变化与 V₃₀相关(r=0.345,P=0.013),CK-MB、LDH、α-HBDH变化与 V₂₅、V₃₀均相关(r=0.465~0.376,P=0.001~0.005);三维适形放疗前后CK-MB、LDH变化与 V₃₀相关(r=0.330、0.274,P=0.014、0.033),α-HBDH变化与 V₂₅、V₃₀、V₃₅相关(r=0.270~0.331,P=0.046~0.014)。当放疗剂量>50 Gy时AST、LDH、α-HBDH变化与 V₂₅、V₃₀相关(r=0.256~0.359,P=0.019~0.006),CK-MB变化与 V₃₀相关(r=0.233,P=0.037);≤50 Gy时仅 V₅、V₄₅与CK变化相关(r=0.581、0.536,P=0.023、0.043)。结论 心脏体积剂量与三维放疗前后心肌酶水平变化有一定相关性,提示心脏DVH参数有助于评价放疗诱导的心肌损伤。     

直肠癌术后固定剂量率容积调强放射治疗的初步研究

目的 初步探讨固定剂量率容积调强在直肠癌术后盆腔放射治疗中的可行性。方法 选取10例直肠癌放疗患者,利用RayStation计划系统为每例患者制定可变剂量率容积调强(VDR-VMAT)、固定剂量率容积调强(CDR-VMAT)和5野静态调强(5F-sIMRT)计划。运用剂量体积直方图评估三种计划的靶区、危及器官和正常组织剂量学参数,评估机器总跳数(MU)和计划执行时间。结果 靶区剂量方面,三种计划的靶区D2%、D_mean、D98%、HI和CI在总体上均有差异(P＜0.001)。CDR-VMAT与VDR-VMAT相比较,D2%、D_mean、D98%、HI、CI差异均无统计学意义;CDR-VMAT与5F-sIMRT相比较,D2%减小1.55 Gy(P=0.005)、D_mean减小0.99 Gy(P=0.005)、D98%增大0.60 Gy(P=0.03)、HI值减小(P=0.008)、CI值增大(P=0.008)。危及器官方面,三种计划的膀胱D_mean、V₄₅、V₄₀,小肠D_mean、D_max、V₄₅,左右股骨头D_mean在总体上均有差异(P＜0.05);小肠V₄₀、V₃₅,左右股骨头V₄₅、V₄₀在总体上均无差异(P＞0.05)。CDR-VMAT与VDR-VMAT相比较,膀胱、小肠、左右股骨头的各剂量学参数差异无统计学意义;CDR-VMAT与5F-sIMRT相比较,膀胱D_mean减小3.05 Gy(P=0.005)、V₄₀减小0.88%(P=0.042),小肠D_mean减小1.75 Gy(P=0.002)、D_max减小1.70 Gy(P＜0.001),左、右股骨头D_mean减小(P=0.008,0.042)。正常组织低剂量受照体积方面,三种计划的正常组织受照低剂量体积除V₁₀(P=0.497)之外,V₅、V₁₅、V₂₀、V₂₅和V₃₀在总体上均有差异(P＜0.001)。CDR-VMAT与VDR-VMAT相比,V₅、V₁₀、V₁₅、V₂₀、V₂₅和V₃₀差异无统计学意义;与5F-sIMRT相比,CDR-VMAT的V₅减小1.18%(P=0.005)、V₁₅减小0.61%(P=0.022)、V₃₀减小0.80%(P=0.022),V₁₀、V₂₀和V₂₅差异无统计学意义。CDR-VMAT计划的MU为(668.51±45.92),比VDR-VMAT(574.13±50.20)增加16.44%,比5F-sIMRT(537.19±37.34)增加24.45%;CDR-VMAT计划执行时间(3.34±0.22)min是VDR-VMAT(1.76±0.04)min的近两倍,比5F-sIMRT(4~6)min稍短。结论 CDR-VMAT可形成与VDR-VMAT一样高质量的计划,较5F-sIMRT有更优的靶区覆盖率、危及器官保护和正常组织低剂量受照体积。但CDR-VMAT计划的MU比VDR-VMAT和5F-sIMRT增多;执行时间比VDR-VMAT长,比5F-sIMRT稍短。CDR-VMAT初始成本较低,有望为不具备可变剂量率的直线加速器提供额外的旋转放疗的选择。     

放射生物模型在乳腺癌放疗计划评价中的比较

目的 比较分析不同放射生物模型的特性,以寻求评价乳腺癌放疗计划合理的放射生物模型.方法 比较预测放射性肺炎发生率和放射性心脏病死亡率的NTCP两种模型和TCP四种模型,计算相同DVH数据所得结果的差异;并分析同一模型中,输入DVH数据的形式、参数的选择等对结果的影响.结果 假设全肺平均照射30 Gy剂量时,NTCP-RSM模型预测的放射性肺炎发生率为32%,NTCP-Lyman模型预测的为54%.以发生放射性心脏病死亡率1%为例,NTCP-RSM模型对应的心脏平均照射剂量为28 Gy,而NTCP-Lyman模型对应的为40 Cy.应用LQ-Poisson-TCP模型、Poisson-TCP模型、Logit-TCP模型和Zaider-TCP模型,计算相同DVH数据库的平均TCP分别为21.1%、38.4%、41.0%和80.8%(P=0.000).采用不同栅格大小计算的NTCP/TCP结果差别较小.计算时采用物理剂量或LQED2剂量对NTCP/TCP结果有一定影响,采用物理剂量时的结果稍大.ft.和p值、肿瘤细胞密度、D50值和DVH简化方法对TCP的影响显著(P=0.000).结论 评价和优化乳腺癌放疗计划选择放射生物模型时,以NTCP-Lyman模型计算放射性肺炎和以NTCP-RSM模型计算放射性心脏病死亡率比较合理.TCP模型以LQ-Poisson-TCP模型比较符合临床实际.影响预测结果最大的是模型参数值的选取,选择时需要加以注意.这些模型目前有助于对不同治疗模式进行研究和比较,而不是给出对临床实际结果的精确预测.     

T1-2期鼻咽癌RTOG推荐靶区与中国推荐靶区IMRT计划之间后组颅神经NTCP差异性分析

目的 通过研究T_1-2期鼻咽癌IMRT中基于RTOG推荐靶区和中国靶区IMRT计划之间后组颅神经NTCP的差异,为鼻咽癌IMRT中后组颅神经保护提供剂量体积效应依据。方法 选取2013—2015年间T₁、T₂期鼻咽癌病例共20例,分别在其CT定位影像上勾画后组颅神经。根据RTOG0225推荐方法(RTOG靶区方法)和2010年中国鼻咽癌临床分期工作委员会推荐的靶区定义方法(中国靶区方法)勾画靶区和设计治疗计划,计算两种靶区定义方法之间后组颅神经受量及NTCP差异性。结果 RTOG靶区和中国靶区方法的左、右侧后组颅神经受量D_max分别为(7450±273)、(7294±309) cGy和(7361±160)、(7190±395) cGy (左、右侧P=0.018、0.042);D_mean分别为(6735±285) 、(6660±333) cGy和(6446±429) 、(6299±467) cGy (左、右侧P=0.000、0.000);NTCP分别为(60±10)%、(57±13)%和(51±15)%、(45±17)%(左、右侧P=0.000、0.000)。结论 鼻咽癌IMRT中将后组颅神经作为常规OAR来精确勾画并进行剂量评估和NTCP预测是可行的;后组颅神经的NTCP与其靶区接受剂量和受照体积密切相关;中国靶区方法的后组颅神经受量和NTCP都明显小于RTOG靶区方法。     

胸中下段食管癌放疗±化疗后心源性死亡的初步分析

目的 分析接受根治性放疗±化疗的胸中下段食管癌患者治疗后心源性死亡的影响因素。方法 对符合入组条件的140例患者进行回顾分析,分析其一般临床资料及治疗计划DVH显示的心脏相关剂量体积因素对心源性死亡影响。计数资料组间比较行χ²检验,计量资料组间比较行独立样本t检验,应用Logistic法行心脏剂量体积及临床相关影响因素分析。结果 共死亡103例,其中心源性死亡8例(7.8%)。心源性死亡的单因素分析结果显示年龄≥70岁(P=0.033)、有糖尿病史(P=0.043)、胸下段食管癌(P=0.017)及食管病变造影长度>5 cm (P=0.013)为危险因素,心脏D_mean(P=0.032)及心脏V₅₀(P=0.045)为影响因素;ROC曲线分析结果显示心脏D_mean(P=0.044)能有效预测患者,其临界值为3325 cGy;Logistic多因素分析结果显示食管病变造影长度(P=0.013)及心脏D_mean(P=0.034)为影响因素。结论 食管病变造影长度及心脏D_mean为患者影响因素,且心脏D_mean大小能很好预测患者,建议在制定治疗计划时注意控制心脏D_mean受量。     

3DCRT计划中不同肺定义对肺癌放疗的影响

目的 探讨3DCRT计划中双肺－GTV、CTV、PTV三种定义下正常肺DVH参数差异及对RP的预测价值。方法 对2006—2010年间行3DCRT的147例NSCLC患者分别定义双肺－GTV、CTV、PTV正常肺并收集相关DVH剂量学信息,比较参数值差异及其对RP的预测价值。剂量学参数间差异采用成组t检验,用ROC曲线分析各剂量学因素的预测价值。结果 以MLD为例,双肺－GTV定义下与双肺－CTV、PTV的差值分别为(1.16±0.96)、(3.45±1.43) Gy。同一患者不同定义下MLD最大差值为8.73 Gy。双肺－GTV下MLD对≥2、3级RP预测价值优于双肺－CTV、PTV的,表现为ROC曲线下面积较大,分别为0.614和0.678、0.566和0.602、0.551和0.616(P=0.024和0.056、0.269和0.226、0.317和0.167)。对肺V₅—V₅₀的分析也得出类似结论。结论 基于不同定义下所得的剂量学参数存在较大差异,临床不能忽视;基于双肺－GTV所得相关剂量学参数对RP预测价值最佳,建议采用。     

Early clinical and radiological pulmonary complications following breast cancer radiation therapy: NTCP fit with four different models.

OBJECTIVE: To fit four different NTCP (Normal Tissue Complication Probability) models to prospectively collected data on short-term pulmonary complications following breast cancer radiotherapy (RT). MATERIALS/METHODS: Four hundred and seventy-five breast cancer patients, referred to the Radiotherapy Department at Stockholm S?der Hospital (1994-1998) for adjuvant post-operative RT were prospectively followed for pulmonary complications 1, 4 and 7 months after the completion of RT. Eighty-seven patients with complete dose-volume histogram (DVH) of the ipsilateral lung were selected for the present analysis. Mean dose to the ipsilateral lateral lung ranged from 2.5 to 18Gy (median 12Gy). Three different endpoints were considered: (1) clinical pneumonitis scored according to CTC-NCIC criteria: asymptomatic (grade 0) vs grade 1 and grade 2; (2) radiological changes assessed with diagnostic chest X-ray: no/slight radiological changes vs moderate/severe; (3) radiological changes assessed with CT: no/slight vs moderate/severe. Four NTCP models were used: the Lyman model with DVH reduced to the equivalent uniform dose (LEUD), the Logit model with DVH reduced to EUD, the Mean Lung Dose (MLD) model and the Relative Seriality (RS) model. The data fitting procedure was done using the maximum likelihood analysis. The analysis was done on the entire population (n=87) and on a subgroup of patients treated with loco-regional RT (n=44). RESULTS: 24/87 patients (28%) developed clinical pneumonitis; 28/81 patients (35%) had radiological side effects on chest X-rays and 11/75 patients (15%) showed radiological density changes on Computed Tomography (CT). The analysis showed that the risk of clinical pneumonitis was a smooth function of EUD (calculated from DVH using n=0.86+/-0.10, best fit result). With LEUD, the relationship between EUD and NTCP could be described with a D(50) of 16.4Gy+/-1.1Gy and a steepness parameter m of 0.36+/-0.7. The results found in the overall population were substantially confirmed in the subgroup of patients treated with loco-regional RT. CONCLUSIONS: A large group of prospective patient data (87 pts), including grade 1 pneumonitis, were analysed. The four NTCP models fit quite accurately the considered endpoints. EUD or the mean lung dose are robust and simple parameters correlated with the risk of pneumonitis. For all endpoints the D(50) values ranged in an interval between 10 and 20Gy.     

肺癌同期放化治疗中放射性肺损伤的相关因素分析

 目的 观察三维适形放疗联合同期化疗治疗局部晚期非小细胞肺癌中放射性肺损伤情况,对其相关因 素进行分析,寻找合理的预测性 指标。 方法 47例符合入组条件的非小细胞肺癌患者接受三维适形放疗及同期化疗。处方剂量为60Gy常规 放疗,同期化疗方案为NP方案,对三维适形治疗计划及临床资料进行单因素、多因素分析,评 价肺损伤情况。 结果 （1）完全缓解3例, 部分缓解42例,总有效率为95.74%,1年生存率75.78%。全组发生急性放 射性肺炎0级2例,1级20 例,2级17例,3级8例,无4级放射性肺炎发生。（2）与严重放射性肺炎发生呈正相关的剂量 学因素为MLD、肺NTCP,肺V5、 V15、V20。临床资料中仅发现肿瘤GTV与严重放射性肺炎发生相关;多因素分析显示全肺平均 剂量为放射性肺炎的独立影 响因素。 结论 剂量学因素（MLD、肺NTCP,肺V5、V15、V20）可以较好地预测严重放射性肺炎的发生,全肺 平均剂量是放射性肺炎发生的独立影响因素。     

Prediction of radiation pneumonitis by dose - volume histogram parameters in lung cancer--a systematic review.

BACKGROUND AND PURPOSE: To perform a systematic review of the predictive ability of various dose-volume histogram (DVH) parameters (V(dose), mean lung dose (MLD), and normal tissue complication probability (NTCP)) in the incidence of radiation pneumonitis (RP) caused by external-beam radiation therapy. METHODS AND MATERIALS: Studies assessing the relationship between CT-based DVH reduction parameters and RP rate in radically treated lung cancer were eligible for the review. Synonyms for RP, lung cancer, DVH and its associated parameters (NTCP, V(20), V(30), MLD) were combined in a search strategy involving electronic databases, secondary reference searching, and consultation with experts. Individual or group data were abstracted from the various reports to calculate operating characteristics and odds ratios for the different DVH metrics. RESULTS: A total of 12 published studies and two abstracts were identified. Eleven studies assessed V(dose), seven assessed MLD, and eight assessed NTCP. Nine studies exclusively analyzed the association between various DVH metrics and RP risk. Five studies also analyzed other patient, tumor, and treatment variables in conjunction with standard DVH metrics. A direct comparison between studies and the generation of summary statistics (i.e. meta-analysis) could not be achieved due to significant predictive and outcome variable heterogeneity. Most studies did show an association between DVH parameters and RP risk. However, overall accuracy, sensitivity, specificity, and positive predictive value were generally poor to fair for all three classes of DVH metrics. CONCLUSIONS: An association between DVH parameters and RP risk has been demonstrated in the literature. However, the ideal DVH metric with excellent operating characteristics, either alone or in a model with other predictive variables, for RP risk prediction has not yet been identified. Several recommendations for reporting and conduct of future research into the association between DVH metrics and RP risk are provided.     

Comparing different NTCP models that predict the incidence of radiation pneumonitis. Normal tissue complication probability

PURPOSE: To compare different normal tissue complication probability (NTCP) models to predict the incidence of radiation pneumonitis on the basis of the dose distribution in the lung. METHODS AND MATERIALS: The data from 382 breast cancer, malignant lymphoma, and inoperable non-small-cell lung cancer patients from two centers were studied. Radiation pneumonitis was scored using the Southwestern Oncology Group criteria. Dose-volume histograms of the lungs were calculated from the dose distributions that were corrected for dose per fraction effects. The dose-volume histogram of each patient was reduced to a single parameter using different local dose-effect relationships. Examples of single parameters were the mean lung dose (MLD) and the volume of lung receiving more than a threshold dose (V(Dth)). The parameters for the different NTCP models were fit to patient data using a maximum likelihood analysis. RESULTS: The best fit resulted in a linear local dose-effect relationship, with the MLD as the resulting single parameter. The relationship between the MLD and NTCP could be described with a median toxic dose (TD(50)) of 30.8 Gy and a steepness parameter m of 0.37. The best fit for the relationship between the V(Dth) and the NTCP was obtained with a D(th) of 13 Gy. The MLD model was found to be significantly better than the V(Dth) model (p <0.03). However, for 85% of the studied patients, the difference in NTCP calculated with both models was <10%, because of the high correlation between the two parameters. For dose distributions outside the range of the studied dose-volume histograms, the difference in NTCP, using the two models could be >35%. For arbitrary dose distributions, an estimate of the uncertainty in the NTCP could be determined using the probability distribution of the parameter values of the Lyman-Kutcher-Burman model. CONCLUSION: The maximum likelihood method revealed that the underlying local dose-effect relation for radiation pneumonitis was linear (the MLD model), rather than a step function (the V(Dth) model). Thus, for the studied patient population, the MLD was the most accurate predictor for the incidence of radiation pneumonitis.     

非小细胞肺癌三维适形放疗放射性肺损伤剂量学因素分析

目的 观察非小细胞肺癌三维适形放疗患者急性放射性肺炎的发生情况,并分析其与各剂 量学因素的关系。方法 收集2010年6月—2010年12月间首程行三维适形放疗的非小细胞肺癌患者68 例。从治疗计划系统的剂量体积直方图中获取以下剂量学参数：处方剂量、平均肺剂量(MLD)、正常 肺体积剂量（V5~V50间隔5 Gy）等,分别采用单因素及多因素分析各个剂量学参数与放射性肺炎之 间的关系,并采用受试者工作特征曲线寻找预测界值。结果 V5是放射性肺炎发生的独立预后因素 （χ2=5.15,P=0.023）。患者肺脏的V5超过57%时放射性肺炎的发生率可能会增加。结论 临床医师 在审核治疗计划时,除了要考虑V20、V30、MLD等常用参数外,还应关注V5的大小。     

非小细胞肺癌三维适形放疗剂量体积直方图参数与放射性肺损伤CT分级的关系

目的 探讨剂量体积直方图(DVH)参数与非小细胞肺癌(NSCLC)三维适形放疗(3D-CRT)后放射性肺损伤CT分级的关系.方法 将3D-CRT治疗后CT随访6个月以上的169例Ⅰ～Ⅲ期NSCLC患者,按随访CT放射性肺损伤的表现分级(0～4级),并分为CT阳性组(2～4级)和CT阴性组(0～1级).从放疗计划中获取患者的DVH参数,分析DVH参数与放射性肺损伤CT分级的关系,评价DVH参数对放射性肺损伤的预测价值.结果 不同CT分级的全肺及患侧肺正常组织并发症概率(NTCP)值差异有统计学意义,随着CT分级的增加,NTCP相应增大.不同CT分级的全肺及患侧肺平均肺受照剂量(MLD)差异有统计学意义,随着CT分级的增加,全肺及患侧肺MLD相应增大.不同CT分级的全肺及患侧肺V20、V30和V40差异均有统计学意义,随着CT分级的增加,全肺及患侧肺V20、V30、V40相应增大.不同CT分级患者健侧肺的DVH参数差异无统计学意义.全肺、患侧肺DVH参数与患侧肺CT分级联系紧密,其中患侧肺NTCP与CT分级关联度最强(η=0.522).结论 NTCP、MID、V20、V30、V40等DVH参数与NSCLC 3D-CRT后放射性肺损伤的CT分级密切相关,可以作为评价及优化放疗计划的指标,以减少放疗后放射性肺损伤的发生.     

Comparison of three accelerated partial breast irradiation techniques: treatment effectiveness based upon biological models.

BACKGROUND AND PURPOSE: Accelerated partial breast irradiation (APBI) is being studied in a phase III randomized trial as an alternative to whole breast irradiation (WBI) for early stage breast cancer patients. There are three methods for APBI: multi-catheter brachytherapy (MCT), MammoSite brachytherapy (MST), or 3D conformal (3DCRT). There is a paucity of data comparing among methods. Using a linear-quadratic (LQ) model, we evaluated the anticipated efficacy among the APBI methods for equivalent uniform dose (EUD), Tumor Control Probability (TCP), and Normal Tissue Complication Probability (NTCP). MATERIALS AND METHODS: Treatment plans from five patients treated by each APBI modality were retrospectively selected. Dose-volume-histograms (DVH) for planning target volume (PTV), breast, and lung were generated. The LQ parameters alpha=0.3Gy(-1) and alpha/beta=10Gy were used for calculations. The values of EUD, TCP, and NTCP were calculated based on DVHs. RESULTS: The average EUD (normalized to 3.4Gy BID) for the MCT, MST, and 3DCRT APBI was 35, 37.2, and 37.6Gy. When normalized to 2Gy fractionation these become, 42.2, 46.4, and 46.9Gy. Average TCP for MCT, MST, and 3DCRT PBI was 94.8%, 99.1%, and 99.2%. The NTCP values for breast and lung were low for all three methods. CONCLUSIONS: The EUD for PTV and TCP were most similar in MST and 3DCRT APBI and were lower in MCT APBI. This questions the equivalence of the three APBI modalities that are currently being evaluated in the NSABP-B39/RTOG 0413 protocol.