Abstract：
Stereotactic body radiation therapy (SBRT) has been increasingly used for the ablation of liver tumours. CyberKnife and proton beam therapy (PBT) are two advanced treatment technologies suitable to deliver SBRT with high dose conformity and steep dose gradients. However, there is very limited data comparing the dosimetric characteristics of CyberKnife to PBT for liver SBRT. PBT and CyberKnife plans were retrospectively generated using 4DCT datasets of ten patients who were previously treated for hepatocellular carcinoma (HCC, N = 5) and liver metastasis (N = 5). Dose volume histogram data was assessed and compared against selected criteria; given a dose prescription of 54 Gy in 3 fractions for liver metastases and 45 Gy in 3 fractions for HCC, with previously published consensus-based normal tissue dose constraints. Comparison of evaluation parameters showed a statistically significant difference for target volume coverage and liver, lungs and spinal cord (p < 0.05) dose, while chest wall and skin did not indicate a significant difference between the two modalities. A number of optimal normal tissue constraints was violated by both the CyberKnife and proton plans for the same patients due to proximity of tumour to chest wall. PBT resulted in greater organ sparing, the extent of which was mainly dependent on tumour location. Tumours located on the liver periphery experienced the largest increase in organ sparing. Organ sparing for CyberKnife was comparable with PBT for small target volumes.
摘要：
立体定向身体放射治疗（SBRT）已越来越多地用于肝肿瘤的消融。射波刀和质子束治疗（PBT）是两种先进的治疗技术，适用于提供具有高剂量一致性和陡峭剂量梯度的SBRT。然而,有非常有限的数据比较的剂量特征的Cyberknife的PBT肝脏SBRT。使用先前接受肝细胞癌治疗的10例患者的4DCT数据集回顾性生成PBT和Cyberknife计划（HCC，N=5)和肝转移(N=5)。对剂量体积直方图数据进行了评估，并将其与选定的标准进行了比较；给定剂量处方：肝转移的3个部分为54Gy，HCC的3个部分为45Gy，与先前发表的基于共识的正常组织剂量限制。评估参数的比较显示，目标体积覆盖率和肝脏具有统计学上的显着差异，肺和脊髓（p<0.05）剂量，而胸壁和皮肤没有显示两种模式之间的显着差异。由于肿瘤靠近胸壁，同一患者的射波刀和质子计划都违反了许多最佳的正常组织约束。PBT导致更大的器官保留，其程度主要取决于肿瘤的位置。位于肝脏外围的肿瘤经历了最大的器官保留增加。对于小目标体积，射波刀的器官保留与PBT相当。
