Pötter Richard, Haie-Meder Christine, Van Limbergen Erik, Barillot Isabelle, De Brabandere Marisol, Dimopoulos Johannes, Dumas Isabelle, Erickson Beth, Lang Stefan, Nulens An, Petrow Peter, Rownd Jason, Kirisits Christian
Department of Radiotherapy and Radiobiology, Medical University of Vienna, Austria.
Radiother Oncol. 2006 Jan;78(1):67-77. doi: 10.1016/j.radonc.2005.11.014. Epub 2006 Jan 5.
The second part of the GYN GEC ESTRO working group recommendations is focused on 3D dose-volume parameters for brachytherapy of cervical carcinoma. Methods and parameters have been developed and validated from dosimetric, imaging and clinical experience from different institutions (University of Vienna, IGR Paris, University of Leuven). Cumulative dose volume histograms (DVH) are recommended for evaluation of the complex dose heterogeneity. DVH parameters for GTV, HR CTV and IR CTV are the minimum dose delivered to 90 and 100% of the respective volume: D90, D100. The volume, which is enclosed by 150 or 200% of the prescribed dose (V150, V200), is recommended for overall assessment of high dose volumes. V100 is recommended for quality assessment only within a given treatment schedule. For Organs at Risk (OAR) the minimum dose in the most irradiated tissue volume is recommended for reporting: 0.1, 1, and 2 cm3; optional 5 and 10 cm3. Underlying assumptions are: full dose of external beam therapy in the volume of interest, identical location during fractionated brachytherapy, contiguous volumes and contouring of organ walls for >2 cm3. Dose values are reported as absorbed dose and also taking into account different dose rates. The linear-quadratic radiobiological model-equivalent dose (EQD2)-is applied for brachytherapy and is also used for calculating dose from external beam therapy. This formalism allows systematic assessment within one patient, one centre and comparison between different centres with analysis of dose volume relations for GTV, CTV, and OAR. Recommendations for the transition period from traditional to 3D image-based cervix cancer brachytherapy are formulated. Supplementary data (available in the electronic version of this paper) deals with aspects of 3D imaging, radiation physics, radiation biology, dose at reference points and dimensions and volumes for the GTV and CTV (adding to [Haie-Meder C, Pötter R, Van Limbergen E et al. Recommendations from Gynaecological (GYN) GEC ESTRO Working Group (I): concepts and terms in 3D image-based 3D treatment planning in cervix cancer brachytherapy with emphasis on MRI assessment of GTV and CTV. Radiother Oncol 2005;74:235-245]). It is expected that the therapeutic ratio including target coverage and sparing of organs at risk can be significantly improved, if radiation dose is prescribed to a 3D image-based CTV taking into account dose volume constraints for OAR. However, prospective use of these recommendations in the clinical context is warranted, to further explore and develop the potential of 3D image-based cervix cancer brachytherapy.
妇科GEC ESTRO工作组建议的第二部分聚焦于宫颈癌近距离治疗的三维剂量体积参数。这些方法和参数是基于不同机构（维也纳大学、巴黎居里研究所、鲁汶大学）的剂量学、影像学及临床经验开发并验证的。推荐使用累积剂量体积直方图（DVH）来评估复杂的剂量异质性。GTV、高危临床靶区（HR CTV）和低危临床靶区（IR CTV）的DVH参数是分别给予各自体积90%和100%的最小剂量：D90、D100。建议用处方剂量150%或200%所包含的体积（V150、V200）来全面评估高剂量体积。仅在给定治疗计划内，推荐用V100进行质量评估。对于危及器官（OAR），建议报告受照剂量最高的组织体积中的最小剂量：0.1、1和2立方厘米；可选5和10立方厘米。基本假设为：感兴趣体积内接受外照射的全剂量、分次近距离治疗期间位置相同、相邻体积以及对大于2立方厘米的器官壁进行轮廓勾画。剂量值报告为吸收剂量，并考虑不同的剂量率。近距离治疗应用线性二次放射生物学模型等效剂量（EQD2），也用于计算外照射剂量。这种形式主义允许在同一患者、同一中心内进行系统评估，并通过分析GTV、CTV和OAR的剂量体积关系在不同中心之间进行比较。制定了从传统宫颈癌近距离治疗向基于三维图像的近距离治疗过渡阶段的建议。补充数据（可在本文电子版中获取）涉及三维成像、放射物理学、放射生物学、参考点剂量以及GTV和CTV的尺寸与体积等方面（补充了[海耶 - 梅德C，波特R，范·林根E等。妇科（GYN）GEC ESTRO工作组（I）的建议：基于三维图像的宫颈癌近距离治疗三维治疗计划中的概念和术语，重点是GTV和CTV的MRI评估。放射肿瘤学2005；74：235 - 245]）。如果根据基于三维图像的CTV规定放射剂量并考虑OAR的剂量体积限制，预计包括靶区覆盖和危及器官保护的治疗比可显著提高。然而，有必要在临床环境中前瞻性地应用这些建议，以进一步探索和开发基于三维图像的宫颈癌近距离治疗的潜力。
