Jameson Michael G, Kumar Shivani, Vinod Shalini K, Metcalfe Peter E, Holloway Lois C
Liverpool and Macarthur Cancer Therapy Centres, Australia; Centre for Medical Radiation Physics, University of Wollongong, Australia; Ingham Institute of Applied Medical Research, Australia.
Liverpool and Macarthur Cancer Therapy Centres, Australia; Ingham Institute of Applied Medical Research, Australia; South Western Sydney Clinical School, University of New South Wales, Australia.
Radiother Oncol. 2014 Sep;112(3):332-6. doi: 10.1016/j.radonc.2014.03.019. Epub 2014 May 19.
Contouring variation is a well know uncertainty in modern radiotherapy. This study investigates the relationship between contouring variation, tumor control probability (TCP) and equivalent uniform dose (EUD) for conformal non-small cell lung cancer (NSCLC) radiotherapy.
Seven patients were retrospectively recruited to the study and multiple PTV contours were generated based on CT and PET imaging by three observers. Plans were created for each PTV volume. Volumes were analyzed geometrically using volume, location, dimension and conformity index (CI). Radiobiological plan analysis consisted of two TCP models and EUD. Spearman's correlation coefficient (ρ) was used to quantify the association between geometric variation and radiobiological metrics.
The variation in CI and TCP for the study was 0.66-0.90% and 0.19-0.68%. Changes in lateral dimension and volume were significantly correlated with TCP and EUD with an average ρ of -0.49 and 0.43 (p<0.01) respectively.
TCP and geometric contour variation show significant correlation. This correlation was most significant for changes in lateral dimensions of PTV volumes. This association may be used in the assessment of contouring protocol violations in multicenter clinical trials and aid in the design of future contouring studies.
在现代放射治疗中，靶区勾画差异是一个众所周知的不确定因素。本研究调查了适形非小细胞肺癌（NSCLC）放射治疗中靶区勾画差异、肿瘤控制概率（TCP）和等效均匀剂量（EUD）之间的关系。
回顾性招募7例患者参与本研究，由三名观察者基于CT和PET影像生成多个计划靶体积（PTV）轮廓。为每个PTV体积制定计划。使用体积、位置、尺寸和适形指数（CI）对体积进行几何分析。放射生物学计划分析包括两个TCP模型和EUD。采用Spearman相关系数（ρ）量化几何差异与放射生物学指标之间的关联。
本研究中CI和TCP的差异分别为0.66 - 0.90%和0.19 - 0.68%。横向尺寸和体积的变化与TCP和EUD显著相关，平均ρ分别为 - 0.49和0.43（p<0.01）。
TCP与几何靶区勾画差异显示出显著相关性。这种相关性在PTV体积的横向尺寸变化方面最为显著。这种关联可用于评估多中心临床试验中靶区勾画方案的违规情况，并有助于未来靶区勾画研究的设计。
