Department of Radiation Oncology, University Medical Centre Utrecht, The Netherlands.
Radiother Oncol. 2010 Mar;94(3):339-45. doi: 10.1016/j.radonc.2009.10.011. Epub 2009 Nov 26.
To perform a qualitative and quantitative comparison of different treatment planning methods used in different centres for MRI-based brachytherapy (BT) of cervical cancer.
Two representative patients with advanced cervical cancer (1 "limited volume case"; 1 "extensive volume case") were planned for brachytherapy (BT) with a tandem-ring applicator by six different centres. During a workshop all centres produced an institutional standard plan and an MRI-based adaptive treatment plan for each case. Optimisation was based on the fractionation schedule (HDR, PDR) and method according to the institutional protocol.
The loading pattern, dwell times, shape of the point A isodose varied considerably between institutional standard plans, as did dose-volume parameters for high risk CTV (HR-CTV) and also for the D(2cc) for OAR, violating the dose-volume constraints in many situations. During optimisation, the centres stayed as close as possible to the standard loading pattern and dwell times. The dose distributions and dose-volume parameters between the plans from the different centres became much more comparable after optimisation. The prescribed dose to the HR-CTV could be achieved in the limited volume case by all centres, in the extensive case only if additional needles were applied.
Treatment planning for gynaecologic brachytherapy based on different traditions shows less variation in regard to target coverage and OAR dose, when 3D image-based optimisation is performed with a uniform prescription protocol.
对不同中心用于基于 MRI 的宫颈癌近距离放射治疗（BT）的不同治疗计划方法进行定性和定量比较。
为 2 名晚期宫颈癌患者（1 例“局限性容积病例”；1 例“广泛性容积病例”）规划使用双环施源器进行 BT，由 6 个不同中心进行。在一个研讨会上，所有中心都为每个病例制作了机构标准计划和基于 MRI 的适应性治疗计划。优化是根据分割方案（HDR、PDR）和机构协议中的方法进行的。
机构标准计划之间的加载模式、驻留时间、A 点等剂量曲线的形状差异很大，高危CTV（HR-CTV）的剂量-体积参数以及 OAR 的 D（2cc）也有很大差异，在许多情况下违反了剂量-体积限制。在优化过程中，各中心尽可能接近标准加载模式和驻留时间。经过优化后，不同中心之间的计划的剂量分布和剂量-体积参数变得更加可比。在局限性容积病例中，所有中心都可以达到 HR-CTV 的规定剂量，在广泛性病例中，如果需要额外的针，则可以达到规定剂量。
基于不同传统的妇科近距离放射治疗计划，当使用统一的处方协议进行基于 3D 图像的优化时，在靶区覆盖和 OAR 剂量方面的变化较小。
