| 雷俊杰,刘济人,潘孝鹏,等.两种测量方式下宫颈癌超长靶区γ通过率的分布情况[J].中华放射医学与防护杂志,2025,45(9):870-875.Lei Junjie,Liu Jiren,Pan Xiaopeng,et al.Distribution of gamma pass rates for ultra-long target volumes of cervical cancer based on two measurement methods[J].Chin J Radiol Med Prot,2025,45(9):870-875 |
| 两种测量方式下宫颈癌超长靶区γ通过率的分布情况 |
| Distribution of gamma pass rates for ultra-long target volumes of cervical cancer based on two measurement methods |
| 投稿时间：2024-09-28 |
| DOI：10.3760/cma.j.cn112271-20240928-00387 |
| 中文关键词: 宫颈癌 超长靶区 剂量验证 γ通过率 |
| 英文关键词:Cervical cancer Ultra-long target volume Dose verification γ-pass rate |
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| 中文摘要: |
| 目的 比较移动摆位中心单独测量与分段测量后拼接两种方式下宫颈癌超长靶区γ通过率的差异,并分析分段测量时安装散射块对验证结果的影响。方法 回顾性选取螺旋断层治疗系统超长靶区的宫颈癌患者24例(靶区长度23.5~36.0 cm),采用两种方法测量其验证通过率。一是移动摆位中心单独测量,将患者治疗计划移植至ArcCheck模体,计算剂量分布并导出,对比测量与计算结果的γ通过率;二是利用ArcCheck的merge功能分两段测量后拼接,导入50 cm虚拟模体计算验证计划,正反两次摆位测量并融合生成拼接文件,计算γ通过率,同时安装散射块后重复测量。以不同剂量标准的γ通过率评价结果。结果 移动摆位中心单独测量与加散射块的拼接方式在各种评价标准下的γ通过率差异均无统计学意义(P > 0.05);而与不加散射块的拼接方式相比,在3%/2 mm绝对剂量(全局)标准下γ通过率的差异有统计学意义(Z = -2.31,P = 0.02)。另外,安装散射块可提高分段测量的验证通过率,其中3%/2 mm相对剂量γ通过率的差异有统计学意义(Z = -2.11,P = 0.04)。结论 使用ArcCheck测量宫颈癌超长靶区时,建议优先采用移动摆位中心单独测量的方式。若需使用分段测量进行拼接,则应在测量时安装散射块,以提高验证通过率,确保剂量验证的准确性。 |
| 英文摘要: |
| Objective To compare gamma pass rates for ultra-long target volumes of cervical cancer between individual measurements by moving the phantom isocenter and segmented measurements combined with merging and to assess the influence of scattering blocks on verification result during segmented measurements. Methods A retrospective study was conducted on 24 cervical cancer patients with ultra-long target volumes (lengths: 23.5–36.0 cm) treated using helical tomotherapy. Two measurement methods were used to verify the gamma pass rates: individual measurements by moving the phantom isocenter and segmented measurements combined with merging. For the first measurement method, the patients' treatment plans were transferred to the ArcCheck phantom. After the dose distribution was calculated and exported, the gamma pass rates measured and calculated were compared. For the segmented measurements, a 50-cm-long virtual phantom was imported, and the treatment plans of patients were then transferred to the virtual phantom. Afterward, the dose distribution of the virtual phantom was calculated and exported. Then, two dose measurements were conducted under upward and downward setup of the ArcCheck phantom. Two dose measurement files were obtained and then fused to produce a merged file. Then, the γ pass rates were calculated. Repeated measurements were conducted after scattering blocks were installed. The γ-pass rates were assessed using varying dose criteria. Results Under various evaluation criteria, no statistically significant differences in γ pass rates were observed between the individual measurements by moving the phantom isocenter and the segmented measurement in the presence of scattering blocks (P > 0.05). In contrast, there existed statistically significant differences in γ pass rates between the individual measurements by moving the phantom isocenter and the segmented measurement in the absence of scattering blocks according to the (global) criterion of 3%/2 mm absolute dose (Z = -2.31,P = 0.02). Additionally, the segmented measurement in the presence of scattering blocks enhanced pass rates, with statistical significant difference under the criterion of 3%/2 mm relative dose (Z = -2.11, P = 0.04). Conclusions In the case where ArcCheck is used to measure the dose distribution of ultra-long target volumes in cervical cancer, it is advisable to preferentially use individual measurements by moving the phantom isocenter. When segmented measurements combined with merging are required, it is necessary to install scattering blocks during measurements. This will improve γ-pass rates during verification and ensure the accuracy of dose verification. |
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