基于iCBCT分析前列腺癌调强放疗中的靶区位移  

Analysis of target location shift in intensity modulated radiotherapy for prostate cancer based on iCBCT

作　　者：李展维 罗谕 王少金 陈炫光[2] 刘洋 许森奎[2] 丁振华 LI Zhanwei;LUO Yu;WANG Shaojin;CHEN Xuanguang;LIU Yang;XU Senkui;DING Zhenhua(Department of Radiology,School of Public Health,Southern Medical University,Guangdong Guangzhou 510000,China;Department of Radiation Oncology,Sun Yat-sen University Cancer Center,Guangdong Guangzhou 510000,China)

机构地区：[1]南方医科大学公共卫生学院放射医学系,广东广州510000 [2]中山大学肿瘤防治中心放疗科,广东广州510000

出　　处：《现代肿瘤医学》2024年第17期3285-3290,共6页Journal of Modern Oncology

基　　金：广东省医学科学技术研究基金(编号:A2017613);广东省食管癌研究所科技计划(编号:Q202107)。

摘　　要：目的:研究iCBCT引导前列腺癌调强放疗中盆腔淋巴引流区和前列腺精囊腺靶区位移的差异性,为临床上选择合理的图像引导策略提供参考依据。方法:回顾性选取2023年01月至2023年09月在中山大学肿瘤防治中心进行调强放疗的21例前列腺癌患者,要求患者在定位及治疗前充盈膀胱、排空直肠,对患者治疗前扫描的iCBCT影像分别以盆腔骨性结构、前列腺精囊腺为参考进行离线配准(自动配准后手动调整),分别评估盆腔淋巴引流区、前列腺精囊腺的靶区位移误差,得到左右(left-right,LR)、头脚(superior-inferior,SI)和前后(anterior-posterior,AP)方向的位移数值,分析两个区域位移的差异性、相关性,并且计算相对位移,应用公式M_(PTV)=2.5Σ+0.7σ计算PTV外扩边界。结果:盆腔淋巴引流区、前列腺精囊腺在左右、头脚、前后平移方向位移误差分别为LR:(0.27±0.58)mm vs (0.31±0.61)mm;SI:(0.53±0.91)mm vs (0.68±0.98);AP:(2.03±1.86)mm vs (2.79±2.52)mm。头脚、前后方向位移差异有统计学意义(H=4.577、5.035,P<0.05),左右方向为高度相关(r=0.736),头脚方向为中度相关(r=0.542),前后方向为极低度相关(r=0.190)。两个区域在LR、SI和AP的相对位移5 mm的百分比分别为4.9%、5.3%和29.2%。盆腔淋巴引流区LR、SI、AP方向PTV外扩范围分别为1.08 mm、1.96 mm、6.38 mm,前列腺精囊腺LR、SI、AP方向PTV外扩范围为1.20 mm、2.39 mm、8.74 mm。结论:在前列腺癌调强放疗中,盆腔淋巴引流区和前列腺精囊腺靶区在分次治疗间前后方向位移较大,且两区域靶区在前后方向容易发生较大的相对位移,无法通过影像引导校正误差,应尽可能保持膀胱和直肠状态与CT定位时一致。Objective:To investigate the disparity in target localization between the pelvic lymphatic drainage area and the prostate seminal vesicle gland in iCBCT-guided intensity modulated radiotherapy for prostate cancer,with the intention of providing valuable insights for selecting an optimal image guidance strategy in clinical practice.Methods:Twenty-one patients with prostate cancer who underwent intensity modulated radiotherapy in the Sun Yat-Sen University Cancer Center from January 2023 to September 2023 were retrospectively selected.Prior to positioning and treatment,the patients were instructed to ensure bladder filling and rectal emptying.Offline registration(manual adjustment after automatic registration) was performed on the pre-treatment iCBCT images based on pelvic bone structure as well as prostate seminal vesicle gland.The displacement errors in the pelvic lymphatic drainage area and prostate seminal vesicle gland target locations were evaluated separately,obtaining displacement values in left-right(LR),superior-inferior(SI),and anterior-posterior(AP) directions.The differences and correlations of displacement between these two regions were analyzed,along with calculating relative displacement.The expansion boundary of PTV was determined using the formula M_(PTV)=2.5Σ+0.7σ.Results:The positioning errors of pelvic lymphatic drainage area and prostate seminal vesicle gland target were as follows:LR:(0.27±0.58)mm vs(0.31±0.61)mm,SI:(0.53±0.91)mm vs(0.68±0.98)mm,AP:(2.03±1.86)mm vs(2.79±2.52)mm.Significant differences were observed in SI and AP(H=4.577,5.035,P<0.05).Displacement in LR showed a high correlation coefficient(r=0.736),while moderate correlation coefficient in SI(r=0.542).However,the displacement in AP displayed a very weak correlation coefficient(r=0.190).The relative displacements in LR,SI,AP exceeded the threshold value of 5 mm by percentages of 4.9 %,5.3 %,and 29.2 %respectively.The PTV expansion ranges of pelvic lymphatic drainage area in LR,SI and AP directions were 1.08 mm,1.96 mm a

关 键 词：前列腺癌 调强放疗 iCBCT 图像引导 配准方法 

分 类 号：R735.25[医药卫生—肿瘤]