Department of Medical Physics, Apollo Proton Cancer Centre, Chennai, Tamil Nadu, India.
Department of Medical Physics, Apollo Proton Cancer Centre, Chennai, Tamil Nadu, India.
Clin Oncol (R Coll Radiol). 2023 Apr;35(4):227-236. doi: 10.1016/j.clon.2022.12.003. Epub 2023 Jan 4.
To carry out a comprehensive critical appraisal of image-guided intensity-modulated proton therapy practice for craniospinal irradiation (CSI).
An image-guided intensity-modulated proton therapy database of 45 consecutive paediatric patients with central nervous system embryonal malignancies treated between January 2019 and April 2022 were critically appraised for demography, diagnosis, treatment planning strategy and treatment delivery accuracy.
Most patients (median age: 7.5 years; male:female ratio: 34:11) had medulloblastoma (56%), followed by recurrent ependymoma (19%), pinealoblastoma (5%), germ cell (5%) and others (15%). The dose to the planning target volume-craniospinal (PTV-CS; length 39.06-79.59 cm) varied from 21 to 35 GyRBE, whereas the combined median dose to craniospinal and boost was 54 GyRBE. In all patients, the 95% isodose line covered the cribriform plate completely and optic nerves mostly, with a median V95% of 100% and 82.96%, keeping Dmax to the lens <3.9 GyRBE. In skeletally immature patients (88.38%), the anterior vertebral body was completely covered in 18.18% and underdosed in 70.15% of the cases, resulting in a median Dmean of 10.11 GyRBE to the oesophagus. Lateral spine coverage was maintained on the edges of the vertebral body in 52.2%, whereas it extended beyond in 48.8%. The median V98% for clinical target volumes and V95% for PTVs of the brain, spine and craniospinal were >97%, with excellent conformity (0.89) and homogeneity (0.07) indices for PTV-CS. All neurological organs at risk received a median Dmax ranging from 36 to 44 GyRBE from the combined CSI and boost regimens. Analysis of patient-specific quality assurance results revealed that 545 (97.67%) planar dosage verification had gamma (3% at 3 mm) values >95%. The online patient set-up verification showed translational and rotational deviation within 2 mm and 0.5° in 88-94% and 97% of the cases. Systematic and random error were within 0.90 mm and 1.71 mm in translation and 0.1° and 0.2° in rotation.
A change in practice pattern was observed. The findings from our comprehensive critical appraisal add to the growing library of CSI practice and may serve as a reference for inter-institutional comparison.
对颅脊髓照射（CSI）的影像引导强度调制质子治疗实践进行全面的批判性评估。
对 2019 年 1 月至 2022 年 4 月期间连续 45 例接受中枢神经系统胚胎性恶性肿瘤治疗的儿科患者的影像引导强度调制质子治疗数据库进行了批判性评估，评估内容包括人口统计学、诊断、治疗计划策略和治疗交付准确性。
大多数患者（中位年龄：7.5 岁；男：女比例：34:11）患有髓母细胞瘤（56%），其次是复发性室管膜瘤（19%）、松果体母细胞瘤（5%）、生殖细胞瘤（5%）和其他（15%）。计划靶区体积-颅脊髓（PTV-CS；长度 39.06-79.59cm）的剂量从 21 到 35GyRBE 不等，而颅脊髓和增强的联合中位剂量为 54GyRBE。在所有患者中，95%等剂量线完全覆盖筛板和视神经大部分，中位 V95%为 100%和 82.96%，保持晶状体的 Dmax<3.9GyRBE。在骨骼未成熟的患者（88.38%）中，18.18%的病例完全覆盖前椎体，70.15%的病例剂量不足，导致食管的中位 Dmean 为 10.11GyRBE。在 52.2%的病例中，侧脊柱覆盖在椎体边缘，而在 48.8%的病例中则延伸超过椎体边缘。脑、脊柱和颅脊髓的临床靶区和 PTV 的中位 V98%和 V95%均>97%，PTV-CS 的适形度（0.89）和均匀度（0.07）指数良好。所有神经器官危险区从 CSI 和增强联合治疗方案中接受了中位 Dmax 范围从 36 到 44GyRBE。对患者特异性质量保证结果的分析表明，545（97.67%）个平面剂量验证的伽马（3%在 3mm）值>95%。在线患者设置验证显示，88-94%和 97%的病例中，平移和旋转偏差在 2mm 和 0.5°以内。系统和随机误差在平移中为 0.90mm 和 1.71mm，在旋转中为 0.1°和 0.2°。
观察到实践模式的改变。我们全面的批判性评估结果增加了 CSI 实践的不断增长的知识库，可作为机构间比较的参考。
