University College London, Centre for Medical Image Computing, London, United Kingdom.
Department of Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom.
Br J Radiol. 2023 Jun 1;96(1146):20230058. doi: 10.1259/bjr.20230058. Epub 2023 May 10.
To identify variables predicting interfractional anatomical variations measured with cone-beam CT (CBCT) throughout abdominal paediatric radiotherapy, and to assess the potential of surface-guided radiotherapy (SGRT) to monitor these changes.
Metrics of variation in gastrointestinal (GI) gas volume and separation of the body contour and abdominal wall were calculated from 21 planning CTs and 77 weekly CBCTs for 21 abdominal neuroblastoma patients (median 4 years, range: 2 - 19 years). Age, sex, feeding tubes, and general anaesthesia (GA) were explored as predictive variables for anatomical variation. Furthermore, GI gas variation was correlated with changes in body and abdominal wall separation, as well as simulated SGRT metrics of translational and rotational corrections between CT/CBCT.
GI gas volumes varied 74 ± 54 ml across all scans, while body and abdominal wall separation varied 2.0 ± 0.7 mm and 4.1 ± 1.5 mm from planning, respectively. Patients < 3.5 years ( = 0.04) and treated under GA ( < 0.01) experienced greater GI gas variation; GA was the strongest predictor in multivariate analysis ( < 0.01). Absence of feeding tubes was linked to greater body contour variation ( = 0.03). GI gas variation correlated with body ( = 0.53) and abdominal wall ( = 0.63) changes. The strongest correlations with SGRT metrics were found for anterior-posterior translation ( = 0.65) and rotation of the left-right axis ( = -0.36).
Young age, GA, and absence of feeding tubes were linked to stronger interfractional anatomical variation and are likely indicative of patients benefiting from adaptive/robust planning pathways. Our data suggest a role for SGRT to inform the need for CBCT at each treatment fraction in this patient group.
This is the first study to suggest the potential role of SGRT for the management of internal interfractional anatomical variation in paediatric abdominal radiotherapy.
确定在儿童腹部放射治疗中，通过锥形束 CT（CBCT）测量的分次间解剖变化的预测变量，并评估表面引导放射治疗（SGRT）监测这些变化的潜力。
从 21 例腹部神经母细胞瘤患者的 21 次计划 CT 和 77 次每周 CBCT 中计算胃肠道（GI）气体体积和体廓与腹壁分离的变化指标（中位数为 4 岁，范围：2-19 岁）。探讨年龄、性别、喂养管和全身麻醉（GA）作为解剖变化的预测变量。此外，还对 GI 气体变化与体廓和腹壁分离的变化以及 CT/CBCT 之间的平移和旋转校正的模拟 SGRT 指标进行了相关性分析。
所有扫描中，GI 气体体积变化 74 ± 54ml，而体廓和腹壁分离分别从计划时变化 2.0 ± 0.7mm 和 4.1 ± 1.5mm。年龄 < 3.5 岁（ = 0.04）和 GA 治疗（ < 0.01）的患者 GI 气体变化更大；GA 是多变量分析中最强的预测因素（ < 0.01）。无喂养管与更大的体廓变化相关（ = 0.03）。GI 气体变化与体廓（ = 0.53）和腹壁（ = 0.63）变化相关。与 SGRT 指标相关性最强的是前后平移（ = 0.65）和左右轴旋转（ = -0.36）。
年龄较小、GA 和无喂养管与更强的分次间解剖变化相关，可能表明患者受益于适应性/稳健性计划途径。我们的数据表明，在这个患者群体中，SGRT 可能有助于指导每个治疗分次时是否需要进行 CBCT。
这是第一项表明 SGRT 在管理儿童腹部放射治疗中内部分次间解剖变化方面具有潜力的研究。
