宫颈癌术后盆腔螺旋断层调强和固定野调强技术的剂量学比较

  目的  比较对宫颈癌术后患者应用螺旋断层调强放疗(helical tomotherapy, HT)和固定野调强放疗(fixed-field intensity-modulated radiotherapy, FF-IMRT)两种计划方式进行放射治疗的剂量学差异。  方法  选择10例宫颈癌术后进行调强放疗的患者行CT模拟定位, 勾画靶区及危及器官, 对同一CT图像设计HT计划和FF-IMRT计划。评估靶区及危及器官的剂量分布。  结果  HT计划组和FF-IMRT计划组靶区覆盖度均满足临床处方剂量要求。与FF-IMRT计划组相比, HT组的计划靶区(planning target volume, PTV)95%、PTV100%覆盖度增加, PTV105%覆盖度降低、Dmean及Dmax均明显降低(P=0.000), 适形度指数和均匀性指数均优于FF-IMRT计划组(P=0.000)。与FF-IMRT计划组相比, HT计划组的膀胱V₄₀降低约7%(P=0.000), Dmax平均值降低1.7 Gy(P=0.000);直肠V₄₀降低约8%(P=0.000);小肠V₃₀、V₄₀分别降低4%、3%(P=0.002, P=0.000), Dmax平均值降低2 Gy(P=0.000);骨髓V₃₀增加约5%(P=0.001), 左右股骨头D₅差异无统计学意义; 马尾神经Dmax的平均值降低约2 Gy(P=0.030)。全身V₂₀、V₃₀、V₄₀分别降低2%、1.3%、0.6%(P < 0.01)。  结论  宫颈癌患者采用HT技术, 靶区均匀性指数及适形度指数均较FF-IMRT技术明显提高, 膀胱、直肠、小肠中高剂量区的体积进一步降低。HT技术在宫颈癌术后的临床应用中具有可行性, 可作为一种新的照射方式推广。     

自动勾画临床靶区和危及器官用于制定早期乳腺癌保乳术后放疗计划

目的 观察自动勾画临床靶区(CTV)和危及器官(OAR)用于制定乳腺癌保乳术后放疗计划的可行性。方法 选取52例女性早期右侧乳腺癌保乳术后患者，由医师于胸部CT图像中手动勾画CTV和OAR。采用AccuLearning^TM软件对其中40例(训练集)CT图像进行训练，生成自动勾画模型，并以之对其余12例(测试集)CT图像进行自动勾画，辅以手动修改获得CTV及OAR;分别根据手动和自动勾画的CTV和OAR制定放疗计划，即Plan-RS和Plan-DL,对比其CTV及OAR剂量学参数及勾画时间。结果 测试集Plan-RS与Plan-DL的CTV剂量学参数差异均无统计学意义(P均>0.05);二者间健侧肺、心脏及健侧乳腺的平均放疗剂量(D_mean)差异有统计学意义(P均<0.05),其余OAR剂量学参数差异均无统计学意义(P均>0.05)。手动勾画和自动勾画CTV平均用时分别为1 006 s和239 s,前者长于后者(P<0.05);除脊髓外，自动勾画其他OAR用时较手动勾画缩短(P均<0.001)。结论 自动勾画CTV...     

直肠癌术前容积调强与固定野调强技术的剂量学比较

  目的  比较对直肠癌术前患者应用固定野调强(fixed-field intensity-modulated radiotherapy, FF-IMRT)和容积调强(volumetric modulated arc therapy, VMAT)两种计划方式进行术前放射治疗的剂量学差异。  方法  选择15例直肠癌术前进行调强放疗的患者行CT模拟定位, 勾画靶区及危及器官, 对同一CT图像设计FF-IMRT计划和VMAT计划。评估靶区及危及器官的剂量分布。  结果  VMAT计划组和FF-IMRT计划组靶区覆盖度均能满足处方剂量要求。与FF-IMRT计划组相比, VMAT计划组计划靶区(planning target volume, PTV)105%覆盖度、Dmean及Dmax均增加(P=0.011, P=0.017, P=0.006), 适形度指数减低(P=0.008), 而均匀性指数差异无统计学意义(P=0.193)。与FF-IMRT计划组相比, VMAT计划组膀胱V₅₀增加约15%(P=0.009), Dmax平均值增加0.7 Gy(P=0.003);小肠V₃₀降低10%(P=0.004), Dmax平均值增加0.9 Gy(P=0.000);骨髓V₁₀、V₃₀、V₄₀分别降低2%、10%、10%(P=0.000, P=0.000, P=0.000), Dmean平均值降低1.7 Gy(P=0.000);左右股骨头D₅分别降低3.2 Gy、2.4 Gy(P=0.000, P=0.000);全身V₁₀、V₂₀、V₃₀、V₄₀也明显降低(P=0.003, P=0.000, P=0.000, P=0.004)。VMAT计划组较FF-IMRT计划组机器跳数(monitor units, MU)平均值减少50%(P=0.000)。  结论  直肠癌术前患者采用VMAT技术, 可以获得等同于或优于FF-IMRT计划的剂量分布, 患者治疗时间明显缩短, MU明显降低。     

胰腺癌不同调强方式的剂量学比较

  目的  比较胰腺癌术后患者固定野调强放疗(fixed-field intensity-modulated radiotherapy, FF-IMRT)与容积调强放疗(volumetric modulated arc therapy, VMAT)的剂量学差异, 为临床选择合适的照射技术提供参考。  方法  2011年6月至12月在北京协和医院行放疗的10例胰腺癌术后患者, 分别根据其同一CT模拟定位图像设计FF-IMRT计划和VMAT计划, 处方剂量50 Gy/25次。分析剂量体积直方图曲线, 评估靶区、危及器官和正常组织的剂量分布, 并比较二者机器跳数(monitor units, MU)和治疗时间的差别。  结果  FF-IMRT计划和VMAT计划的靶区剂量分布差异无统计学意义(P > 0.05)。与FF-IMRT计划相比, VMAT计划中肝脏、胃、小肠、全身的V₅明显升高(P均 < 0.05), 而肝脏的V₁₀和V₂₀, 胃的V₁₀, 小肠的V₁₀、V₂₀、V₅₀, 左肾的V₂₀, 右肾的V₂₀、V₃₀、D_mean、D_max, 以及全身的V₁₀、V₂₀有不同程度下降(P均 < 0.05), 脊髓的D_max升高1.85 Gy(P=0.04)。FF-IMRT计划与VMAT计划的MU分别为619.60±117.18和492.70±51.56(t=3.18, P=0.01)。VMAT计划的MU较FF-IMRT计划减少了20.48%。  结论  胰腺癌患者选择VMAT计划, 可以在不降低计划水平上的剂量分布的前提下, 大大减少MU, 缩短治疗时间。     

宫颈癌患者锥形束CT影像剂量计算的算法修正

目的 利用修正算法对宫颈癌患者锥形束CT（CBCT）影像进行修正,探讨CBCT影像剂量计算的准确性。方法 采用CIRS-062电子密度模体分别在Brilliance CT Big Bore 4D-CT模拟定位机及Truebeam加速器机载CBCT上执行CT扫描,获得计划CT（pCT）和CBCT的CT值-相对电子密度曲线。采用直方图匹配算法对CBCT影像的CT值进行修正,得到修正后的CBCT（mCBCT）。将25例宫颈癌患者的调强放疗计划分别移植到模体和患者的pCT、CBCT和mCBCT上进行剂量计算,比较其绝对剂量和剂量分布的差异。结果 模体等中心处,CBCT计算的绝对剂量与pCT计算的绝对剂量偏差为0.87%±0.24%,mCBCT与pCT的偏差为0.05%±0.03%,差异有统计学意义（t=3.625,P<0.05）。患者治疗等中心处,CBCT计算的绝对剂量与pCT计算的绝对剂量偏差为1.05%±0.32%,mCBCT与pCT的偏差为0.18%±0.09%,差异有统计学意义（t=3.023,P<0.05）。靶区剂量分布的剂量体积图显示,mCBCT的剂量分布和pCT的剂量分布相似,而CBCT的剂量分布和pCT的剂量分布差异较明显。结论 CBCT影像经算法修正后,可用于宫颈癌放疗中的剂量计算,并能提高剂量计算的准确性。     

胰腺癌精确放疗的疗效及预后因素

  目的  分析胰腺癌的精确放疗疗效及预后因素。  方法  2003年1月至2012年6月间接受精确放疗的胰腺癌患者102例, 其中根治性放疗54例, 辅助性放疗48例; 三维适形放疗平均16例, 调强放疗86例; 中位放疗剂量50 Gy, 1.8~2.2 Gy/次。13例同步卡培他滨化疗。  结果  所有患者总生存时间(overall survival, OS)为(14±1.2)个月, 无进展生存时间(progress-free survival, PFS)为(9±1.1)个月。1、2、5年生存率分别为63.3%、22.6%、10%。毒性反应包括3级消化道毒性5例, 未发生3、4级血液学和4级消化道毒性反应。单因素分析结果表明, 治疗前体重下降 > 5 kg(P < 0.0001)、T分期(P=0.011)、TNM分期(P=0.007)、是否行肿瘤切除术(P=0.001)是影响OS的预后因素, 同时也是PFS的预后因素。多因素分析结果表明, 肿瘤切除术是OS的预后因素(χ²=5.416, P=0.020)。  结论  在胰腺癌的根治性放疗和辅助性放疗中, 三维适形放疗和调强放疗都可以较好地耐受, 3、4级毒性反应较少, 为放化疗同步及肿瘤放疗剂量的提升提供了可行性; 手术切除提高了OS。     

CT鉴别亚实性肺腺癌亚型

目的 观察CT鉴别亚实性肺腺癌亚型的价值。方法 纳入127例亚实性肺腺癌患者,根据病理结果分为浸润前病变(PL)组(n=33)、微小浸润性腺癌(MIA)组(n=67)及浸润性腺癌(IA)组(n=27),其中分别有23、47及14例存在胸膜下结节;比较3组临床资料及CT表现,对差异有统计学意义的参数行多元有序logistic回归分析,绘制受试者工作特征曲线,评估CT诊断IA的效能。结果 3组患者年龄、结节平均CT值、平均直径、类型、形状、边界特点、血管集束征及空泡征占比差异均有统计学意义(P均<0.05),胸膜下结节胸膜凹陷征占比差异亦有统计学意义(P=0.001)。结节平均CT值和平均直径是为亚实性肺腺癌浸润的独立危险因素[OR=1.009,95%CI(1.004,1.013),P<0.001;OR=1.330,95%CI(1.117,1.583),P=0.001],以结节平均CT值-645.50 HU及平均直径10.00 mm为截断值诊断IA的曲线下面积分别为0.743及0.817,敏感度分别为77.78%及74.07%,特异度分别为63.00%及75.00%。结论 CT可用于鉴别亚实性肺腺癌亚型。     

图像引导放射治疗在宫颈癌患者治疗中的应用

目的探讨中晚期宫颈癌患者应用图像引导放射治疗(IGRT)技术,在提高靶区剂量与减少正常组织受量方面的价值。方法 30例中晚期宫颈癌患者,均给予全程IGRT放疗同步化疗。治疗结束后3个月评价近期疗效,随访评价毒副反应发生情况。观察直肠、小肠和膀胱的受照射剂量和体积。结果 30例患者均完成全程的IGRT,近期疗效显示:CR 26例,PR 4例。1至2年生存率为100%。放疗靶区较精确,OAR的受照剂量为:小肠31.68 Gy;直肠37.19 Gy;膀胱30.13 Gy。毒副反应主要为急、慢性消化道反应和急、慢性血液系统反应。结论在宫颈癌治疗中,IGRT放疗技术可以提高肿瘤放疗的精准性,达到最大程度杀灭肿瘤和保护正常组织器官功能,毒副反应可耐受。     

AccuContour和United Imaging软件自动勾画胸部危及器官

目的 评价2种基于人工智能方法自动勾画软件用于勾画胸部危及器官（OAR）效果的差异。方法 采用AccuContour和United Imaging软件自动勾画24例非小细胞肺癌患者胸部OAR,包括心脏、左肺、右肺、食管及脊髓;以勾画时间、豪斯多夫距离（HD）、形状相似性指数（DSC）及平均最小距离（MDA）评价勾画效果。结果 United Imaging软件勾画时间明显短于AccuContour软件（P<0.05）。2种软件勾画的心脏HD、DSC及MDA差异均具有统计学意义（P均<0.05）。AccuContour软件勾画的右肺HD明显小于United Imaging（P<0.05）。2种软件勾画食管的HD、DSC及MDA差异均有统计学意义（P均<0.05）,United Imaging软件勾画的左肺DSC明显大于AccuContour软件（P<0.05）,MDA则明显小于AccuContour软件（P<0.05）。2种软件勾画的脊髓各项参数差异均无统计学意义（P均>0.05）。结论 AccuContour3.0和United Imaging软件自动勾画胸部不同解剖结构的效果存在差异,且二者各有所长;其勾画肺部和心脏的效果均较好,勾画食管和脊髓效果均稍差。     

螺旋断层调强与固定野调强技术在全乳放疗中的近期临床效果

  目的  研究早期乳腺癌保乳术后应用螺旋断层调强放疗(helical tomotherapy, HT)和固定野调强放疗(fixed-field intensity-modulated radiotherapy, FF-IMRT)的近期疗效和早期临床反应。  方法  2012年9月至2013年3月本院使用HT(HT组)和FF-IMRT(FF-IMRT组)进行保乳术后全乳放疗的早期乳腺癌患者共24例, 每组12例, 术后病理分期0~ⅡB期, 全乳放疗剂量46~50 Gy/23~25次。其中接受化疗者11例(45.8%), 接受内分泌治疗者18例(75%)。对两组靶区及危及器官剂量分布进行评估, 对放疗毒性反应及美容效果进行评价。  结果  与FF-IMRT组相比, HT组的计划靶区(planning target volume, PTV)105%、PTV110%高剂量区减少(P=0.000, P=0.023), 靶区的均匀性和适形度改善(P=0.003, P=0.002)。患侧肺的V₅、V₂₀、Dmean(P=0.002, P=0.001, P=0.000), 双肺的V₅、V₂₀、Dmean(P=0.010, P=0.002, P=0.009)及心脏的V₅、V₂₀(P=0.033, P=0.030)等受量降低。HT组出现Ⅰ、Ⅱ级放射性皮炎者分别有10例(83.3%)、2例(16.7%), FF-IMRT组出现Ⅰ、Ⅱ级放射性皮炎者分别有11例(91.7%)、1例(8.3%); 所有患者均未出现放射性肺炎。HT组患者美容效果为满意者12例(100%), FF-IMRT组美容效果为满意者11例(91.7%)。两组患者的近期不良反应和美容效果评价差异均无统计学意义。  结论  应用HT与FF-IMRT技术进行保乳术后全乳放疗, 可获得满意的近期临床效果, 长期治疗效果还有待进一步随诊观察。     

残差U-net与先验知识协同模型自动勾画宫颈癌术后临床靶区和危及器官北大核心CSCD

目的搭建残差U-net(RU)网络与先验知识协同(RPKC)自动勾画模型,评估其自动勾画宫颈癌术后患者临床靶区(CTV)和危及器官(OAR)的准确性。方法基于48例(训练集)宫颈癌术后定位CT训练RPKC模型。以临床医师勾画的CTV及OAR为标准,采用戴斯相似系数(DSC)和第95百分位豪斯多夫距离(HD95)评估RPKC模型与RU模型勾画另20例宫颈癌术后患者(测试集)CTV及OAR(包括肠袋、直肠、膀胱、骨盆及双侧股骨头)的准确性。结果RPKC模型自动勾画上述结构的DSC均高于RU模型,其中CTV及肠袋勾画效果差异有统计学意义(P均<0.05);除直肠外,RPKC模型自动勾画的HD95均低于RU模型,二者勾画CTV效果差异差异有统计学意义(P<0.05)。结论RPKC模型能更准确地勾画宫颈癌术后CTV和OAR,有助于提高深度学习自动勾画的临床实用性。     

直肠癌术前容积调强与固定野调强的剂量学研究

目的 　比较对直肠癌术前患者应用固定野调强(fixed-field intensity-modulated radiotherapy,FF-IMRT)和容积调强(volumetric modulated arc therapy,VMAT)两种计划方式进行术前放射治疗的剂量学差异。 方法 　选择15例直肠癌术前进行调强放疗的患者行CT模拟定位,勾画靶区及危及器官,对同一CT图像设计FF-IMRT计划和VMAT计划。评估靶区及危及器官的剂量分布。 结果 　VMAT计划组和FF-IMRT计划组靶区覆盖度均能满足处方剂量要求。与FF-IMRT计划组相比,VMAT计划组计划靶区（planning target volume,PTV）105%覆盖度、Dmean及Dmax均增加（P=0.011,P=0.017,P=0.006）,适形度指数减低（P=0.008）,而均匀性指数差异无统计学意义（P=0.193）。与FF-IMRT计划组相比,VMAT计划组膀胱V50增加约15%（P=0.009）,Dmax平均值增加0.7 Gy（P=0.003）;小肠V30降低10%（P=0.004）,Dmax平均值增加0.9 Gy（P=0.000）;骨髓V10、V30、V40分别降低2%、10%、10%（P=0.000,P=0.000,P=0.000）,Dmean平均值降低1.7 Gy（P=0.000）;左右股骨头D5分别降低3.2 Gy、2.4 Gy（P=0.000,P=0.000）;全身V10、V20、V30、V40也明显降低（P=0.003,P=0.000,P=0.000,P=0.004）。VMAT计划组较FF-IMRT计划组机器跳数（monitor units,MU）平均值减少50%（P=0.000）。 结论 　直肠癌术前患者采用VMAT技术,可以获得等同于或优于FF-IMRT计划的剂量分布,患者治疗时间明显缩短,MU明显降低。     

射线能量和均整特性对直肠癌容积旋转调强计划质量的影响

目的探讨光子射线能量和均整特性对直肠癌VMAT计划质量的影响。方法回顾性选取30例直肠癌术前辅助放疗患者,每例患者使用4种能量模式(6 MV、10 MV、非均整射线6 FFF和10 FFF),用同样的处方和优化函数分别设计VMAT计划。通过剂量体积直方图计算靶区剂量、适形指数(CI)、均匀性指数(HI);统计膀胱、小肠、股骨头和正常组织的剂量;记录每个计划的机器跳数(MU)和计划执行时间,比较4种能量模式下VMAT计划的质量差异。结果 4种计划的靶区的剂量参数D_(98%)、D_(50%)、D_(2%)、CI、HI均值无显著差异;6 FFF、10 FFF能量模式下小肠的最高剂量D_(2%)比6 MV计划的结果小0.7%和1.5%(P0.05),其余OAR的DVH结果无显著差异。正常组织NT的低剂量区域V_(5Gy)、V_(10Gy)和V_(20Gy)、6 FFF、10 FFF计划比6 MV计划的结果分别减少了0.9%、1.4%、1.1%、1.4%和1.2%、2.4%(P0.05)。与6 MV能量计划相比,6 FFF、10MV和10 FFF VMAT计划的MU变化了24%、-3%、29%(P0.05)。结论光子射线能量的变化对直肠癌VMAT计划质量的影响微小,非均整射线可以稍微降低VMAT计划的低剂量照射区体积。     

The predictive value of segmentation metrics on dosimetry in organs at risk of the brain

BackgroundFully automatic medical image segmentation has been a long pursuit in radiotherapy (RT). Recent developments involving deep learning show promising results yielding consistent and time efficient contours. In order to train and validate these systems, several geometric based metrics, such as Dice Similarity Coefficient (DSC), Hausdorff, and other related metrics are currently the standard in automated medical image segmentation challenges. However, the relevance of these metrics in RT is questionable. The quality of automated segmentation results needs to reflect clinical relevant treatment outcomes, such as dosimetry and related tumor control and toxicity. In this study, we present results investigating the correlation between popular geometric segmentation metrics and dose parameters for Organs-At-Risk (OAR) in brain tumor patients, and investigate properties that might be predictive for dose changes in brain radiotherapy.MethodsA retrospective database of glioblastoma multiforme patients was stratified for planning difficulty, from which 12 cases were selected and reference sets of OARs and radiation targets were defined. In order to assess the relation between segmentation quality -as measured by standard segmentation assessment metrics- and quality of RT plans, clinically realistic, yet alternative contours for each OAR of the selected cases were obtained through three methods: (i) Manual contours by two additional human raters. (ii) Realistic manual manipulations of reference contours. (iii) Through deep learning based segmentation results. On the reference structure set a reference plan was generated that was re-optimized for each corresponding alternative contour set. The correlation between segmentation metrics, and dosimetric changes was obtained and analyzed for each OAR, by means of the mean dose and maximum dose to 1% of the volume (Dmax 1%). Furthermore, we conducted specific experiments to investigate the dosimetric effect of alternative OAR contours with respect to the proximity to the target, size, particular shape and relative location to the target.ResultsWe found a low correlation between the DSC, reflecting the alternative OAR contours, and dosimetric changes. The Pearson correlation coefficient between the mean OAR dose effect and the Dice was -0.11. For Dmax 1%, we found a correlation of -0.13. Similar low correlations were found for 22 other segmentation metrics. The organ based analysis showed that there is a better correlation for the larger OARs (i.e. brainstem and eyes) as for the smaller OARs (i.e. optic nerves and chiasm). Furthermore, we found that proximity to the target does not make contour variations more susceptible to the dose effect. However, the direction of the contour variation with respect to the relative location of the target seems to have a strong correlation with the dose effect.ConclusionsThis study shows a low correlation between segmentation metrics and dosimetric changes for OARs in brain tumor patients. Results suggest that the current metrics for image segmentation in RT, as well as deep learning systems employing such metrics, need to be revisited towards clinically oriented metrics that better reflect how segmentation quality affects dose distribution and related tumor control and toxicity.     

Dosimetric Impact of Image-Guided Radiotherapy in Liver Stereotactic Radiotherapy

IntroductionIn the absence of volumetric image-guided radiotherapy (IGRT) with or without intravenous contrast, IGRT with two-dimensional (2D) imaging can improve the accuracy and precision of radiation delivery by correcting the largest sources of geometric uncertainty, facilitating the delivery of higher doses to the tumor and/or reduced doses to normal tissues. The purpose of this work was to estimate dosimetric impact of 2D IGRT for patients undergoing breath hold liver stereotactic body radiotherapy (SBRT).Materials/MethodsOffline residual offsets were determined using orthogonal image pairs acquired with patients positioned with external setup marks (non-IGRT) and following IGRT and repositioning (IGRT) for 30 patients treated with 6-fraction liver SBRT. The diaphragm was used as a surrogate for the liver for craniocaudal positioning, and the vertebral bodies for anterioposterior and right-left positioning, with a 3-mm threshold. The planned dose distributions were shifted by the measured IGRT and non-IGRT offsets. Total doses to target volumes and organs at risk (OAR) were calculated and compared to the prescribed plans.ResultsA total of 643 images (416-MV electronic portal images; 227 kV cone beam computed tomography projection images) were evaluated. Residual non-IGRT offsets frequently exceeded 3 mm (72%), resulting in clinically significant variations from the prescribed minimum planning target volume dose (mean change –6.5 Gy; P =.0150). The population mean reductions in minimum gross tumor volume doses (standard deviation (σ) to 0.5 mL with were 7.2 Gy (6.3) and 4.7 Gy (6.1) for non-IGRT and IGRT, respectively. The mean population increase in maximum OAR dose (to 0.5 mL) was largest for bowel (2.7 Gy, σ = 5.5 Gy) for non-IGRT.ConclusionsIGRT significantly improves concordance of delivered doses with planned doses for liver target volumes and OARs.     

不同体位对妇科肿瘤调强放射治疗剂量学和急性放射性肠炎的影响

目的 探讨妇科肿瘤调强放射治疗（IMRT）采用俯卧位或仰卧位对危及器官剂量学及放射治疗不良反应的影响,优化IMRT体位固定方式。方法 选择42例宫颈癌及子宫内膜癌IMRT患者,按体位固定方式分为俯卧组23例与仰卧组19例。在相同条件下勾画靶区和危及器官并进行治疗计划优化,比较2组患者危及器官剂量-体积关系,分析2组患者急性放射性肠炎的发生情况。 结果 俯卧组小肠接受15~50 Gy照射剂量的体积均小于仰卧组,其中2组接受20、30、40 Gy剂量的体积比较差异均有统计学意义（P均< 0.05）。俯卧组患者结肠接受30、40、45 Gy剂量的体积比较差异均有统计学意义（P均< 0.05）。俯卧组膀胱接受15~50 Gy照射剂量的体积比仰卧组稍升高,但仅接受20 Gy照射剂量的体积在组间比较差异有统计学意义（P < 0.05）。2组患者直肠及股骨头的剂量-体积关系比较差异无统计学意义（P > 0.05）。俯卧组患者消化不良、恶心、呕吐、腹痛和腹泻等急性放射性肠炎的发生率低于仰卧组,但组间比较差异无统计学意义（P均> 0.05）。 结论 妇科肿瘤IMRT采用俯卧位可降低小肠及结肠接受照射剂量。     

膀胱充盈状态对直肠癌盆腔调强适形放疗靶区和邻近危及器官影响的临床研究

目的比较直肠癌术后盆腔适形放疗时膀胱充盈状况与正常组织受照体积的相关性。为直肠癌病人行调强适形放疗时膀胱的充盈提供理论依据。方法选择符合Ⅱ、Ⅲ期直肠癌经腹前切除(Dixon手术)术后盆腔放疗指征的10例患者进行研究:对同一患者相同体位固定时分别处于膀胱充盈与排空状态下,采用同一放疗计划进行膀胱、邻近正常组织受照体积以及靶区体积进行相关性研究。结果膀胱充盈状况与正常组织受照体积相关性:(1)俯卧位、膀胱充盈与排空状态时靶区的剂量分布差异无显著意义;(2)俯卧位、膀胱充盈状态时膀胱受照体积百分比较膀胱处于排空状态时为小,且小肠和结肠受照体积百分比亦较膀胱处于排空状态时小。同时膀胱充盈和排空时小肠受照射的平均剂量分别是(17.1±4.7)Gy和(22.3±4.2)Gy,P=0.003。结论直肠癌术后盆腔调强适形放疗时最好采用全程膀胱充盈状态。     

Dosimetry and outcomes in patients receiving radiotherapy for synchronous bilateral breast cancers

BackgroundSynchronous bilateral breast cancer (SBBC) is rare and there is little evidence describing organs at risk (OAR) and limits to the heart and lungs caused by radiotherapy (RT). Quantifying mean heart dose (MHD) and mean lung dose (MLD) from RT in this patient cohort may lead to better understanding of doses to OAR and resultant effects on clinical outcomes. The primary objective was to assess median MHD and MLD in SBBC, while secondary aims included analyses of 1) factors associated with MHD and MLD, 2) V5 and V20 values and 3) factors associated with clinical outcomes.MethodsPatients planned for adjuvant bilateral whole breast/chest wall (WB) RT from a single institution treated in 2011-2018 were included. Median MHD and MLD (Gy) were stratified by hypofractionated (42.56 Gy/16 fractions, HFRT) and conventional fractionation (50 Gy/ 25 fractions, CFRT) and summarized separately based on the following treatments: 1) locoregional RT, WB tangential RT either 2) no boost 3) sequential boost or 4) simultaneous integrated boost. MHD, MLD, lung V5 and V20 values, and demographics were collected. Linear regression analyses identified factors associated with MHD and MLD and factors associated with clinical outcomes.ResultsA total of 88 patients were included. The median MHD for HFRT and CFRT was 1.99 Gy and 2.94 Gy, respectively. The median MLD for HFRT and CFRT was 6.00 Gy and 10.08 Gy, respectively. MHD and MLD were significantly associated with the occurrence of a cardiac or pulmonary event post-radiation. Patients who had a mastectomy or tumoral muscle involvement were more likely to develop a local recurrence, metastasis or new primary while patients who had a lumpectomy or tumor with a positive estrogen receptor status were less likely to experience these events.ConclusionsFurther investigation should be conducted to identify SBBC RT techniques that mitigate dose to OARs to improve clinical outcomes in bilateral breast patients.