Department of Radiation Oncology, Ansan Hospital, Korea University Medical Center, Jukgeum 123, Ansan, Gyeonggi-do, Republic of Korea.
Strahlenther Onkol. 2013 Apr;189(4):315-20. doi: 10.1007/s00066-012-0271-4. Epub 2013 Feb 28.
The aim of this work was to establish a customized strategy for image-guided radiotherapy during whole breast irradiation. Risk factors associated with extensive errors were assessed.
A series of 176 consecutive breasts in 174 patients were retrospectively assessed. Electronic portal images from 914 medial and 807 lateral directions were reviewed. On the basis of the chest wall, the deviations between the simulation and each treatment were measured. The systematic (Σ) and random error (σ) of population, and the planning target volume (PTV) margin (2 Σ + 0.7σ) were calculated for each direction. Extensive set-up errors were defined as the fraction over the PTV margins in any direction. For extensive set-up errors, χ(2) tests and logistic regression analyses were conducted.
The medial and lateral PTV margins for the right-left, superior-inferior, and anterior-posterior axes and the rotation of collimator were 2.6 and 2.4 mm, 4.6 and 4.6 mm, and 3.1 and 3.3 mm and 2.8 and 2.9 ° and cut-off values for extensive errors were 3, 5, and 4 mm and 3 °, respectively. In χ(2) tests, tumor in upper outer quadrant (p = 0.012) and chest wall thickness ≥ 2.0 cm (p = 0.003) for medial portals and age group (p = 0.036) for lateral portals were associated with extensive errors. In multivariate tests, the extensive error on the initial fraction had a high probability of extensive set-up errors in both medial (OR = 4.26, p < 0.001) and lateral portals (OR = 3.07, p < 0.001).
In terms of the set-up uncertainty during breast irradiation, patients with extensive error in the initial treatment should be closely observed with serial image-guided radiotherapy.
本研究旨在为全乳照射过程中的图像引导放疗制定个体化策略。评估与广泛误差相关的危险因素。
回顾性评估了 174 例患者的 176 个连续乳房。共分析了 914 个内侧和 807 个外侧方向的电子射野影像。基于胸壁，测量了模拟和每次治疗之间的偏差。计算了每个方向的人群系统误差（Σ）和随机误差（σ）、计划靶区（PTV）边界（2Σ+0.7σ）。将任何方向上超过 PTV 边界的部分定义为广泛摆位误差。对于广泛摆位误差，进行卡方检验和逻辑回归分析。
右侧-左侧、上-下和前-后方向以及准直器旋转的内侧和外侧 PTV 边界分别为 2.6 和 2.4mm、4.6 和 4.6mm、3.1 和 3.3mm 和 2.8 和 2.9°，广泛误差的截止值分别为 3、5 和 4mm 和 3°。卡方检验显示，内侧端口肿瘤位于上外象限（p=0.012）和胸壁厚度≥2.0cm（p=0.003）与广泛误差相关，而外侧端口的年龄组（p=0.036）与广泛误差相关。多变量检验显示，内侧（OR=4.26，p<0.001）和外侧（OR=3.07，p<0.001）端口初始分次的广泛误差发生广泛摆位误差的概率较高。
就全乳照射过程中的摆位不确定性而言，初始治疗中存在广泛误差的患者应密切观察并进行连续图像引导放疗。
