表面引导放疗治疗乳腺癌患者的剂量覆盖和屏气分析。
Dose coverage and breath-hold analysis of breast cancer patients treated with surface-guided radiotherapy.
机构信息
Instituut Verbeeten, Klinische fysica & instrumentatie, Postbus 90120, 5000 LA, Tilburg, The Netherlands.
Department of Radiation Oncology, Radboud University Medical Center, Geert Grooteplein 32, 6525 GA, Nijmegen, The Netherlands.
出版信息
Radiat Oncol. 2023 Apr 20;18(1):72. doi: 10.1186/s13014-023-02261-0.
BACKGROUND
Surface-guided radiotherapy (SGRT) is used to ensure a reproducible patient set-up and for intra-fraction motion monitoring. The arm position of breast cancer patients is important, since this is related to the position of the surrounding lymph nodes. The aim of the study was to investigate the set-up accuracy of the arm of patients positioned using SGRT. Moreover, the actual delivered dose was investigated and an extensive breath-hold analysis was performed.
METHODS
84 patients who received local or locoregional breast radiation therapy were positioned and monitored using SGRT. The accuracy of the arm position, represented by the clavicle position, was studied on the anterior-posterior kV-image. To investigate the effect of changes in anatomy and patient set-up, the actual delivered dose was calculated on cone-beam CT-scans (CBCT). A deformable registration of the CT to the CBCT was applied to deform the structures of the CT onto the CBCT. The minimum dose in percentage of the prescribed dose that was received by 98% of different CTV volumes (D98) was determined. An extensive breath-hold analysis was performed and definitions for relevant parameters were given.
RESULTS
The arm position of 77 out of 84 patients in total was successful, based on the clavicle rotation. The mean clavicle rotation was 0.4° (± 2.0°). For 89.8% of the patients who were irradiated on the whole-breast D98 was larger than 95% of the prescribed dose (D98 > 95%). D98 > 95% applied for 70.8% of the patients irradiated on the chest wall. Concerning the lymph node CTVs, D98 > 95% for at least 95% of the patients. The breath-hold analysis showed a mean residual setup error of - 0.015 (± 0.90), - 0.18 (± 0.82), - 0.58 (± 1.1) mm in vertical, lateral, and longitudinal direction, respectively. The reproducibility and stability of the breath-hold was good, with median 0.60 mm (95% confidence interval (CI) [0.66-0.71] mm) and 0.20 mm (95% CI 0.21-0.23] mm), respectively.
CONCLUSIONS
Using SGRT we were able to position breast cancer patients successfully, with focus on the arm position. The actual delivered dose calculated on the CBCT was adequate and no relation between clavicle rotation and actual delivered dose was found. Moreover, breath-hold analysis showed a good reproducibility and stability of the breath-hold. Trial registration CCMO register NL69214.028.19.
背景
表面引导放疗（SGRT）用于确保可重复的患者设置和分次内运动监测。乳腺癌患者的手臂位置很重要，因为这与周围淋巴结的位置有关。该研究的目的是调查使用 SGRT 定位的患者手臂的设置准确性。此外，还对实际传递剂量进行了研究，并进行了广泛的屏气分析。
方法
84 名接受局部或局部区域乳腺癌放疗的患者使用 SGRT 进行定位和监测。通过前-后千伏图像研究锁骨位置代表的手臂位置的准确性。为了研究解剖结构和患者设置的变化的影响，通过锥形束 CT 扫描（CBCT）计算实际传递剂量。对 CT 到 CBCT 的可变形配准应用于将 CT 结构变形到 CBCT 上。确定不同 CTV 体积（D98）的 98%接收到的规定剂量的百分比的最小剂量（D98）。进行了广泛的屏气分析，并给出了相关参数的定义。
结果
总共 84 名患者中有 77 名患者的手臂位置基于锁骨旋转成功。锁骨旋转的平均角度为 0.4°（±2.0°）。对于 89.8%接受全乳房照射的患者，D98 大于规定剂量的 95%（D98>95%）。70.8%接受胸壁照射的患者 D98>95%。对于至少 95%的患者，淋巴结 CTV 的 D98>95%。屏气分析显示，垂直、侧向和纵向方向的残余设置误差平均值分别为-0.015（±0.90）、-0.18（±0.82）和-0.58（±1.1）mm。屏气的重复性和稳定性良好，中位数为 0.60mm（95%置信区间（CI）[0.66-0.71]mm）和 0.20mm（95%CI 0.21-0.23]mm）。
结论
使用 SGRT，我们能够成功定位乳腺癌患者，重点是手臂位置。在 CBCT 上计算的实际传递剂量是足够的，并且未发现锁骨旋转与实际传递剂量之间存在关系。此外，屏气分析显示屏气的重复性和稳定性良好。试验注册 CCMO 注册 NL69214.028.19。
Zotero 插件