School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece.
Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
Biomed Phys Eng Express. 2021 Jul 30;7(5). doi: 10.1088/2057-1976/ac14d1.
Head and neck (H&N) cancer patients often present anatomical and geometrical changes in tumors and organs at risk (OARs) during radiotherapy treatment. These changes may result in the need to adapt the existing treatment planning, using an expert's subjective opinion, for offline adaptive radiotherapy and a new treatment planning before each treatment, for online adaptive radiotherapy. In the present study, a fast methodology is proposed to assist in planning adaptation clinical decision using tumor and parotid glands percentage volume changes during treatment. The proposed approach was applied to 40 Η&Ν cases, with one planning Computed Tomography (pCT) image and CBCT scans for 6 weeks of treatment per case. Deformable registration was used for each patient's pCT image alignment to its weekly CBCT. The calculated transformations were used to align each patient's anatomical structures to the weekly anatomy. Clinical target volume (CTV) and parotid gland volume percentage changes were calculated in each case. The accuracy of the achieved image alignment was validated qualitatively and quantitatively. Furthermore, statistical analysis was performed to test if there is a statistically significant correlation between CTV and parotid glands volume percentage changes. Average MDA for CTV and parotid glands between corresponding structures defined by an expert in CBCTs and automatically calculated through registration was 1.4 ± 0.1 mm and 1.5 ± 0.1 mm, respectively. The mean registration time of the first CBCT image registration for 40 cases was lower than 3.4 min. Five patients show more than 20% tumor volume change. Six patients show more than 30% parotid glands volume change. Ten out of 40 patients proposed for planning adaptation. All the statistical tests performed showed no correlation between CTV/parotid glands percentage volume changes. The aim to assist in clinical decision making on a fast and automatic way was achieved using the proposed methodology, thereby reducing workload in clinical practice.
头颈部 (H&N) 癌症患者在放射治疗过程中经常出现肿瘤和危及器官 (OAR) 的解剖和几何形状变化。这些变化可能导致需要适应现有的治疗计划，使用专家的主观意见，进行离线自适应放疗，并在每次治疗前进行新的治疗计划，进行在线自适应放疗。在本研究中，提出了一种快速方法，以辅助使用肿瘤和腮腺百分比体积变化在治疗期间进行计划适应的临床决策。该方法应用于 40 例 H&N 病例，每个病例有一个计划 CT 图像和 6 周的 CBCT 扫描。为每个患者的 pCT 图像对齐到每周的 CBCT 使用了可变形配准。计算出的变换用于将每个患者的解剖结构对齐到每周的解剖结构。计算了每个病例的临床靶区 (CTV) 和腮腺体积百分比变化。定性和定量验证了所实现的图像对齐的准确性。此外，进行了统计分析，以检验 CTV 和腮腺体积百分比变化之间是否存在统计学上的显著相关性。CTV 和腮腺的平均 MDA 对应结构之间通过专家在 CBCTs 中定义和通过注册自动计算的分别为 1.4 ± 0.1mm 和 1.5 ± 0.1mm。40 例中第一个 CBCT 图像注册的平均注册时间低于 3.4 分钟。5 例患者的肿瘤体积变化超过 20%。6 例患者的腮腺体积变化超过 30%。有 10 例患者建议进行计划适应。所有进行的统计检验均显示 CTV/腮腺体积百分比变化之间无相关性。通过使用提出的方法，实现了以快速和自动的方式辅助临床决策的目标，从而减少了临床实践中的工作量。
