Steenbakkers Roel J H M, Duppen Joop C, Fitton Isabelle, Deurloo Kirsten E I, Zijp Lambert, Uitterhoeve Apollonia L J, Rodrigus Patrick T R, Kramer Gijsbert W P, Bussink Johan, De Jaeger Katrien, Belderbos José S A, Hart Augustinus A M, Nowak Peter J C M, van Herk Marcel, Rasch Coen R N
The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
Radiother Oncol. 2005 Nov;77(2):182-90. doi: 10.1016/j.radonc.2005.09.017. Epub 2005 Oct 26.
To evaluate the process of target volume delineation in lung cancer for optimization of imaging, delineation protocol and delineation software.
Eleven radiation oncologists (observers) from five different institutions delineated the Gross Tumor Volume (GTV) including positive lymph nodes of 22 lung cancer patients (stages I-IIIB) on CT only. All radiation oncologist-computer interactions were recorded with a tool called 'Big Brother'. For each radiation oncologist and patient the following issues were analyzed: delineation time, number of delineated points and corrections, zoom levels, level and window (L/W) settings, CT slice changes, use of side windows (coronal and sagittal) and software button use.
The mean delineation time per GTV was 16 min (SD 10 min). The mean delineation time for lymph node positive patients was on average 3 min larger (P = 0.02) than for lymph node negative patients. Many corrections (55%) were due to L/W change (e.g. delineating in mediastinum L/W and then correcting in lung L/W). For the lymph node region, a relatively large number of corrections was found (3.7 corr/cm2), indicating that it was difficult to delineate lymph nodes. For the tumor-atelectasis region, a relative small number of corrections was found (1.0 corr/cm2), indicating that including or excluding atelectasis into the GTV was a clinical decision. Inappropriate use of L/W settings was frequently found (e.g. 46% of all delineated points in the tumor-lung region were delineated in mediastinum L/W settings). Despite a large observer variation in cranial and caudal direction of 0.72 cm (1 SD), the coronal and sagittal side windows were not used in 45 and 60% of the cases, respectively. For the more difficult cases, observer variation was smaller when the coronal and sagittal side windows were used.
With the 'Big Brother' tool a method was developed to trace the delineation process. The differences between observers concerning the delineation style were large. This study led to recommendations on how to improve delineation accuracy by adapting the delineation protocol (guidelines for L/W use) and delineation software (double window with lung and mediastinum L/W settings at the same time, enforced use of coronal and sagittal views) and including FDG-PET information (lymph nodes and atelectasis).
评估肺癌靶区勾画过程，以优化成像、勾画方案和勾画软件。
来自五个不同机构的11名放射肿瘤学家（观察者）仅在CT上勾画22例肺癌患者（I - IIIB期）的大体肿瘤体积（GTV），包括阳性淋巴结。所有放射肿瘤学家与计算机的交互过程均使用名为“老大哥”的工具进行记录。针对每位放射肿瘤学家和患者，分析以下问题：勾画时间、勾画点数及校正次数、缩放级别、窗宽和窗位（L/W）设置、CT层面变化、侧窗（冠状面和矢状面）的使用情况以及软件按钮的使用情况。
每个GTV的平均勾画时间为16分钟（标准差10分钟）。淋巴结阳性患者的平均勾画时间比淋巴结阴性患者平均长3分钟（P = 0.02）。许多校正（55%）是由于L/W变化（例如在纵隔L/W下勾画，然后在肺L/W下校正）。在淋巴结区域，发现校正次数相对较多（3.7次校正/cm²），表明勾画淋巴结较为困难。在肿瘤 - 肺不张区域，发现校正次数相对较少（1.次校正/cm²），表明将肺不张纳入或排除在GTV内是一个临床决策。经常发现L/W设置使用不当（例如在肿瘤 - 肺区域，所有勾画点的46%是在纵隔L/W设置下勾画）。尽管观察者在头脚方向上的差异较大，标准差为0.72厘米，但分别有45%和60%的病例未使用冠状面和矢状面侧窗。对于更困难的病例，使用冠状面和矢状面侧窗时观察者差异较小。
借助“老大哥”工具开发了一种追踪勾画过程的方法。观察者之间在勾画方式上的差异很大。本研究得出了关于如何通过调整勾画方案（L/W使用指南）和勾画软件（同时具备肺和纵隔L/W设置的双窗口、强制使用冠状面和矢状面视图）以及纳入FDG - PET信息（淋巴结和肺不张）来提高勾画准确性的建议。
