Mock M, Knocke T, Fellner C, Pötter R
Universitätsklinik für Strahlentherapie und Strahlenbiologic, Wien.
Strahlenther Onkol. 1998 Jun;174(6):320-8. doi: 10.1007/BF03038547.
Intracorporal brachytherapy is regarded as the definitive component of treatment for inoperable patients with endometrial carcinoma. Until now the whole uterus has been claimed to represent the target volume independent of individual tumor spread. The purpose of this work is to analyse the correlation between target volume and treated volume using different application- and planning procedures.
In a consecutive series of 10 patients with primary irradiated endometrial carcinoma we analyzed the correlation between target volume and treated volume using either standard 1-channel applicators or individual Heyman-applicators. Application of the ovoids was followed by a planning CT scan for all patients. Based on this, target volume (uterus volume) was estimated on a 3D-planning system. According to the measurable length of the uterus cavity we determined the corresponding standard 1-channel applicator and calculated the respectively treated volume. Estimating the advantages of an optimized treatment planning strategy for individual Heyman-applications were compared the treated volumes, which result from a standardized and optimized treatment planning procedure.
The mean uterus volume was 180 cm3 (range 57 to 316 cm3). Asymmetric uterus configurations with longitudinal or sagittal side differences exceeding 1 cm were found in 40% of the cases. Using standard 1-channel applicators on average 47% (range 25 to 89%) of the uterus volume were enclosed by the treated volume compared to 70% for Heyman-applications. Differentiating these individual applications according to the variable treatment modality values of mean 66% (range 36 to 110%) for the standardized and 73% (range 48 to 95%) for the optimized treatment planning strategy were found. Moreover optimized planning modalities led to an improved coverage of the target volume in 5 out of 10 cases with an increase in volume of 20% on average (range 11 to 32%). In 3 cases changes of less than 5% were noticed (no improvement). In order to protect organs at risk treated volume had to be decreased in 2 cases for 19% and 40% respectively.
Intracavitary brachytherapy of primary endometrial carcinoma was improved by individualized application- and planning procedures, which led to better adaptations of the treated volumes to the target volumes. Nevertheless a complete coverage--corresponding to the primary intent--was not possible. Individualized and optimized brachy-therapy must be performed according to the individual tumor spread and uterus configuration. Therefore, different applicators are required.
体内近距离放射治疗被视为无法手术的子宫内膜癌患者治疗的决定性组成部分。到目前为止，整个子宫一直被认为是代表靶区体积，而与个体肿瘤扩散情况无关。本研究的目的是使用不同的施源器和治疗计划程序分析靶区体积与治疗体积之间的相关性。
在连续的10例接受过初次放疗的子宫内膜癌患者中，我们使用标准单通道施源器或个体化海曼施源器分析靶区体积与治疗体积之间的相关性。所有患者在放置卵形容器后均进行计划CT扫描。基于此，在三维治疗计划系统上估计靶区体积（子宫体积）。根据子宫腔的可测量长度确定相应的标准单通道施源器，并计算相应的治疗体积。为评估个体化海曼施源器优化治疗计划策略的优势，比较了标准化和优化治疗计划程序所得到的治疗体积。
子宫平均体积为180cm³（范围57至316cm³）。40%的病例发现子宫呈不对称形态，其纵径或矢状径差异超过1cm。使用标准单通道施源器时，治疗体积平均包含子宫体积的47%（范围25%至89%），而海曼施源器为70%。根据不同的治疗方式区分这些个体应用，标准化治疗计划策略的平均治疗体积值为66%（范围36%至110%），优化治疗计划策略为73%（范围48%至95%）。此外，优化的计划方式使10例中的5例靶区体积覆盖得到改善，平均体积增加20%（范围11%至32%）。3例中发现变化小于5%（无改善）。为保护危及器官，2例患者的治疗体积分别减少了19%和40%。
个体化的施源器和治疗计划程序改善了原发性子宫内膜癌的腔内近距离放射治疗，使治疗体积更好地适配靶区体积。然而，与最初意图相对应的完全覆盖是不可能实现的。必须根据个体肿瘤扩散情况和子宫形态进行个体化和优化的近距离放射治疗。因此，需要不同的施源器。
